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NFPA 87®, Recommended Practice for Fluid Heaters, 2011 Edition

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Quick PrintChapter 1 Administration1.1* Scope.1.1.1This recommended practice covers Type F, Type G, and Type H fluid heaters and related equipment.

1.1.2Within the scope of this recommended practice, a fluid heater is considered to be any thermal fluid heater or process fluid heater with the following features:

(1) Fluid is flowing under pressure.

(2) Fluid is indirectly heated.

(3) Release of energy from combustion of a liquid or gaseous fuel or an electrical source occurs within the unit.

1.1.3This recommended practice does not apply to the following:

(1) Boilers (which are covered by NFPA 85, Boiler and Combustion Systems Hazards Code, or ANSI/ASME CSD-1, Controls and Safety Devices for Automatically Fired Boilers)

(2) Class A, B, C, or D ovens and furnaces (which are covered by NFPA 86, Standard for Ovens and Furnaces)

(3) Fired heaters in petroleum refineries and petrochemical facilities that are designed and installed in accordance with API 560, Fired Heaters for General Refinery Services; API RP 556, Instrumentation and Control Systems for Fired Heaters and Steam Generators; and API RP 2001, Fire Protection in Refineries

(4) Fired heaters commonly called reformer furnaces or cracking furnaces in the petrochemical and chemical industries

(5) Units that heat air for occupiable space or comfort(6) LP-Gas vaporizers designed and installed in accordance with NFPA 58,

Liquefied Petroleum Gas Code

(7)

(8) Listed equipment with a heating system(s) that supplies a total input not exceeding 150,000 Btu/hr (44 kW)

1.1.4The following types of heaters are covered by this recommended practice:

(1) Class F heaters, which have fluid inside the tubes with a relatively constant flow rate

* Coal or other solid fuel–firing systems

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Quick PrintChapter 2 Referenced Publications2.1 General.The documents or portions thereof listed in this chapter are referenced within this recommended practice and should be considered part of the recommendations of this document.

2.2 NFPA Publications.National Fire Protection Association, 1 Batterymarch Park, Quincy, MA 02169-7471.NFPA 10, Standard for Portable Fire Extinguishers, 2010 edition.

NFPA 11, Standard for Low-, Medium-, and High-Expansion Foam, 2010edition.

NFPA 12, Standard on Carbon Dioxide Extinguishing Systems, 2008 edition.

NFPA 13, Standard for the Installation of Sprinkler Systems, 2010 edition.

NFPA 15, Standard for Water Spray Fixed Systems for Fire Protection, 2007edition.

NFPA 17, Standard for Dry Chemical Extinguishing Systems, 2009 edition.

NFPA 17A, Standard for Wet Chemical Extinguishing Systems, 2009 edition.

NFPA 25, Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, 2011 edition.

NFPA 31, Standard for the Installation of Oil-Burning Equipment, 2006 edition.

NFPA 54, National Fuel Gas Code, 2009 edition.

NFPA 58, Liquefied Petroleum Gas Code, 2011 edition.

NFPA 70®, National Electrical Code®, 2011 edition.

NFPA 79, Electrical Standard for Industrial Machinery, 2007 edition.

NFPA 85, Boiler and Combustion Systems Hazards Code, 2007 edition.

NFPA 86, Standard for Ovens and Furnaces, 2011 edition.

NFPA 750, Standard on Water Mist Fire Protection Systems, 2010 edition.

2.3 Other Publications.2.3.1 API Publications.American Petroleum Institute, 1220 L Street, NW, Washington, DC 20005-4070.

API 560, Fired Heaters for General Refinery Services, 2007.

API RP 556, Instrumentation and Control Systems for Fired Heaters and SteamGenerators, 1997.

API RP 2001, Fire Protection in Refineries, 2005.

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2.3.2 ASME Publications.American Society of Mechanical Engineers, Three Park Avenue, New York, NY10016-5990.

ANSI/ASME Boiler and Pressure Vessel Code, 2007.

ANSI/ASME B31.1, Power Piping, 2007.

ANSI/ASME B31.3, Process Piping, 2008.ANSI/ASME CSD-1, Controls and Safety Devices for Automatically FiredBoilers, 2006.

2.3.3 ASTM Publications.ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959.

ASTM D 396, Standard Specifications for Fuel Oils, 2009.

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2.3.4 IEC Publications.International Electrical Commission, 3 rue de Varembé, P.O. Box 131, CH -1211, Geneva 20, Switzerland.

IEC 61511, Functional Safety: Safety Instruments Systems for the Process Industry Sector, 2004.

2.3.5 UL Publications.Underwriters Laboratories Inc., 333 Pfingsten Road, Northbrook, IL 60062-2096.

UL 795, Standard for Commercial-Industrial Gas HeatingEquipment,2006 2011 .

2.3.6 Other Publications.Merriam-Webster’s Collegiate Dictionary, 11th edition, Merriam-Webster, Inc.,Springfield, MA, 2003.2.4 References for Extracts in Recommendation Sections.NFPA 54, National Fuel Gas Code, 2009 edition.



NFPA 211, Standard for Chimneys, Fireplaces, Vents, and Solid Fuel–BurningAppliances, 2010 edition.

NFPA 820, Standard for Fire Protection in Wastewater Treatment and Collection Facilities, 2008 edition.

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Quick PrintChapter 3 Definitions3.1 General.The definitions contained in this chapter apply to the terms used in thisrecommended practice. Where terms are not defined in this chapter or withinanother chapter, they should be defined using their ordinarily accepted meanings within the context in which they are used. Merriam-Webster’sCollegiate Dictionary, 11th edition, is the source for the ordinarily accepted meaning.3.2 NFPA Official Definitions.3.2.1* Approved.Acceptable to the authority having jurisdiction.

3.2.2* Authority Having Jurisdiction (AHJ).An organization, office, or individual responsible for enforcing the requirements of a code or standard, or for approving equipment, materials, an installation, or a procedure.

3.2.3 Labeled.Equipment or materials to which has been attached a label, symbol, or other identifying mark of an organization that is acceptable to the authority having jurisdiction and concerned with product evaluation, that maintains periodic inspection of production of labeled equipment or materials, and by whose labeling the manufacturer indicates compliance with appropriate standards or performance in a specified manner.

3.2.4* Listed.Equipment, materials, or services included in a list published by an organization that is acceptable to the authority having jurisdiction and concerned with evaluation of products or services, that maintains periodic inspection of production of listed equipment or materials or periodic evaluation of services, and whose listing states that either the equipment, material, or service meets appropriate designated standards or has been tested and found suitable for a specified purpose.

3.2.5 Recommended Practice.A document that is similar in content and structure to a code or standard but that contains only nonmandatory provisions using the word “should” to indicaterecommendations in the body of the text.

3.2.6 Shall.Indicates a mandatory requirement.3.2.7 Should.Indicates a recommendation or that which is advised but not required.

3.2.8 Standard.

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A document, the main text of which contains only mandatory provisions using the word “shall” to indicate requirements and which is in a form generally suitable for mandatory reference by another standard or code or for adoption into law. Nonmandatory provisions shall be located in an appendix or annex, footnote, or fine-print note and are not to be considered a part of the requirements of a standard.3.3 General Definitions.3.3.1 Automatic Fire Check.A flame arrester equipped with a check valve to shut off the fuel gas supplyautomatically if a backfire occurs. [86, 2011]

3.3.2 Backfire Arrester.A flame arrester installed in fully premixed air–fuel gas distribution piping toterminate flame propagation therein, shut off fuel supply, and relieve pressureresulting from a backfire. [86, 2011]

3.3.3 Burner.A device or group of devices used for the introduction of fuel and air into a fluid heater at the required velocities, turbulence, and concentration to maintain ignition and combustion of fuel.

3.3.3.1 Dual-Fuel Burner.A burner designed to burn either fuel gas or liquid fuel but not to burn bothsimultaneously.


3.3.4 Burner Management System.The field devices, logic system, and final control elements dedicated to combustion safety and operator assistance in the starting and stopping of fuel preparation and burning equipment and for preventing misoperation of and damage to fuel preparation and burning equipment.

3.3.5 Combustion Air.The air necessary to provide for the complete combustion of fuel and usually consisting of primary air, secondary air, and excess air. [211, 2010]

3.3.6 Combustion Safeguard.A safety control directly responsive to flame properties that senses the presence or absence of flame and de-energizes the fuel safety shutoff valve in the event of flame failure.

3.3.7 Combustion Safety Circuitry.That portion of the fluid heater control circuitry that contains the contacts,arranged in series ahead of the safety shutoff valve(s) holding medium, for therecommended safety interlocks and the excess temperature limit controller(s).

3.3.8 Controller.3.3.8.1 Programmable Controller.

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A digital electronic system designed for use in an industrial environment thatuses a programmable memory for the internal storage of user-orientedinstructions for implementing specific functions to control, through digital oranalog inputs and outputs, various types of machines or processes. [86, 2011]

3.3.8.2 Temperature Controller.A device that measures the temperature and automatically controls the input of heat into the fluid heater.

3.3.9 Emergency Shutoff Valve.A manual shutoff valve to allow the fuel to be turned off in an emergency.

3.3.10 Equipment Isolation Valve.A manual shutoff valve for shutoff of the fuel to each piece of equipment.

3.3.11 Explosive Range. Flammable Limit.The range of concentration of a flammable gas in air within which a flame can be propagated, with the lowest flammable concentration known as the lower explosive limit (LEL) flammable limit (LFL) , and the highest flammable concentration known as the upper explosive limit (UEL) flammable limit (UFL) .

3.3.12 Fluid Heater.3.3.12.1 Class F Fluid Heater.A heater that has fluid inside the tubes with essentially constant fluid flow rate and where the outlet temperature of the fluid is controlled by modulating the heat input rate to the heater.3.3.12.2 Class G Fluid Heater.A heater that has fluid inside the tubes with modulated fluid flow rate (e.g., by process demand) and where the outlet temperature of the fluid is controlled bymodulating the heat input rate to the heater.

3.3.12.3 Class H Fluid Heater.A heater that has the heat source (combustion or electricity) inside the tube(s) with fluid surrounding the tube.

3.3.13 Fuel Gas.A gas used as a fuel source, including natural gas, manufactured gas, sludge gas, liquefied petroleum gas–air mixtures, liquefied petroleum gas in the vaporphase, and mixtures of these gases. [820, 2008]

3.3.14 Fuel Oil.Grades 2, 4, 5, or 6 fuel oils as defined in ASTM D 396, Standard Specifications for Fuel Oils.

3.3.15 Gas Analyzer.A device that measures concentrations, directly or indirectly, of some or all components in a gas or mixture. [86, 2011]

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3.3.16 Guarded.Covered, shielded, fenced, enclosed, or otherwise protected by means of suitable covers, casings, barriers, rails, screens, mats, or platforms to remove the likelihood of approach or contact by persons or objects to a point of danger.[70: Article 100]


3.3.17* Hardwired.The method of interconnecting signals or interlocks to a logic system or between logic systems using a dedicated interconnection for each individualsignal.

3.3.18 Interlock.3.3.18.1 Excess Temperature Limit Interlock.A device designed to cut off the source of heat if the operating temperature exceeds a predetermined temperature set point.3.3.18.2 Safety Interlock.A device required to ensure safe start-up and safe operation and to cause safe equipment shutdown.

3.3.19 Lower Explosive Limit (LEL). Flammable Limit (LFL). See 3.3.8 3.3.11 , Explosive Range Flammable Limits .

3.3.20 Manufacturer.The entity that directs and controls any of the following: product design, product manufacturing, or product quality assurance; or the entity that assumes the liability for the product or provides the warranty for the product.

3.3.21 Mixer.3.3.21.1 Air–Fuel Gas Mixer.A mixer that combines air and fuel gas in the proper proportions for combustion.[86, 2011]

3.3.21.2 Proportional Mixer.A mixer comprising an inspirator that, when supplied with air, draws all the fuel gas necessary for combustion into the airstream, and a governor, zero regulator, or ratio valve that reduces incoming fuel gas pressure to approximately atmospheric. [86, 2011]

3.3.22 Mixing Blower.A motor-driven blower to supply air–fuel gas mixtures for combustion through one or more fuel burners or nozzles on a single-zone industrial heating appliance or on each control zone of a multizone installation. Mixing machines operated at 10 in. w.c. (2.49 kPa) or less static pressure are considered mixing blowers. [86, 2011]

3.3.23 Mixing Machine.

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An externally powered mechanical device that mixes fuel and air and compresses the resultant mixture to a pressure suitable for delivery to its point of use. [86, 2011]

3.3.24 Operator.An individual trained and responsible for the start-up, operation, shutdown, andemergency handling of the fluid heater and associated equipment.3.3.25 Pilot.A flame that is used to light the main burner. [86, 2011]

3.3.25.1 Interrupted Pilot.A pilot that is ignited and burns during light-off and is automatically shut off at the end of the trial-for-ignition period of the main burner(s). [86, 2011]

3.3.26 Pressure Regulator.Equipment placed in a gas line for reducing, controlling, and maintaining the pressure in that portion of the piping system downstream of the device. [54,2009]3.3.27 Purge.The replacement of a flammable, indeterminate, or high-oxygen-bearing atmosphere with another gas that, when complete, results in a nonflammable final state. [86, 2011]

3.3.28 Resistance Heating System.A heating system in which heat is produced by current flow through a resistiveconductor. [86, 2011]

3.3.29 Safe-Start Check.A checking circuit incorporated in a safety-control circuit that prevents light-off if the flame-sensing relay of the combustion safeguard is in the unsafe (flame-present) position due to component failure within the combustion safeguard or due to the presence of actual or simulated flame. [86, 2011]

3.3.30 Safety Device.An instrument, a control, or other equipment that acts, or initiates action, tocause the fluid heater to revert to a safe condition in the event of equipmentfailure or other hazardous event. [86, 2011]

3.3.31 Safety Relay.A relay listed for safety service. [86, 2011]

3.3.32 Safety Shutoff Valve.A normally closed valve installed in the piping that closes automatically to shutoff the fuel in the event of abnormal conditions or during shutdown.

3.3.33 Scf.One cubic foot of gas at 70°F (21°C) and 14.7 psia (an absolute pressure of 101 kPa). [86, 2011]

3.3.34 Switch.3.3.34.1 Closed Position Indicator Switch.A switch that indicates when a valve is within 0.040 in. (1 mm) of its closed position but does not indicate proof of closure. [86, 2011]3.3.34.2 Differential Pressure Switch.A switch that is activated by a differential pressure that is detected by comparing the pressure at two different points.

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3.3.34.3 Flow Switch.A switch that is activated by the flow of a fluid in a duct or piping system. [86, 2011]

3.3.34.4 Pressure Switch.3.3.34.4.1 Atomizing Medium Pressure Switch.A pressure-activated switch arranged to effect a safety shutdown or to prevent the liquid fuel burner system from being actuated in the event of inadequate atomizing medium pressure.

3.3.34.4.2 High Fuel Pressure Switch.A pressure-activated switch arranged to effect a safety shutdown of the burnersystem in the event of abnormally high fuel pressure. [86, 2011]

3.3.34.4.3 Low Fuel Pressure Switch.A pressure-activated switch arranged to effect a safety shutdown of the burnersystem in the event of abnormally low fuel pressure. [86, 2011]

3.3.34.5* Proof-of-Closure Switch.Non-field-adjustable switch installed in a safety shutoff valve by the manufacturer that activates only after the valve is fully closed.

3.3.35 Tank.


3.3.35.1 Catch Tank.A tank used to capture liquid from drains, relief valves, vents, and overflows.

3.3.35.1 Expansion Tank.A reservoir that allows expansion of a liquid to occur as the liquid is heated.

3.3.36 Trial-for-Ignition Period (Flame-Establishing Period).The interval of time during light-off that a safety control circuit allows the fuel safety shutoff valve to remain open before the combustion safeguard is required to supervise the flame. [86, 2011]

3.3.37* Valve Proving System.A system used to check the closure of safety shutoff valves by detecting leakage. [86, 2011]

3.3.38 Vent Limiter.A fixed orifice that limits the escape of gas from a vented device into the atmosphere. [86, 2011]

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Quick Print


Chapter 4 General4.1 Approvals, Plans, and Specifications.4.1.1Before new equipment is installed or existing equipment is remodeled, complete plans, sequence of operations, and specifications should be submitted for approval to the authority having jurisdiction.

4.1.1.1Plans should be drawn that show all essential details with regard to location,construction, ventilation, piping, and electrical safety equipment. A list of all combustion, control, and safety equipment giving manufacturer, type, andnumber should be included.

4.1.1.2*Wiring diagrams and sequence of operations for all safety controls should beprovided.

4.1.2Any deviation from this recommended practice should require special permission from the authority having jurisdiction.

4.1.3 Electrical.

4.1.3.1*All wiring should be in accordance with NFPA 70, National Electrical Code; NFPA 79, Electrical Standard for Industrial Machinery; and as describedhereafter.


4.1.3.2Where seal leakage or diaphragm failure in a device can result in flammable gas or flammable liquid flow through a conduit or cable to an electrical ignition source, a conduit seal or a cable type that is sealed should be installed.

4.1.3.3Wiring and equipment installed in hazardous (classified) locations should comply with the applicable requirements of NFPA 70, National Electrical Code.

4.1.3.4*The installation of a fluid heater in accordance with this recommended practiceshould not in and of itself require a change to the classification of the fluidheater location.

4.2 Safety Labeling.4.2.1

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A safety design data form or nameplate that states the operating conditions for which the fluid heater was designed, built, altered, or extended should be accessible to the operator.

4.2.2A warning label stating that the equipment should be operated and maintainedaccording to instructions should be provided.4.2.3The warning label should be affixed to the fluid heater or control panel.

4.3 Thermal Fluids and Process Fluids.4.3.1Mixtures of thermal or process fluids should not be used unless such mixtures are in accordance with recommendations of the manufacturer of the fluids.

4.3.2*When a fluid is being changed from one fluid type to another, a study should beperformed to determine that all aspects of the system are compatible with thenew fluid.

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Quick PrintChapter 5 Location and Construction5.1 Location.5.1.1 General.5.1.1.1*Fluid heaters and related equipment should be located so as to protect personnel and buildings from fire or explosion hazards.

5.1.1.2Fluid heaters should be located so as to be protected from damage by external heat, vibration, and mechanical hazards.

5.1.1.3Fluid heaters should be located so as to make maximum use of natural ventilation, to minimize restrictions to adequate explosion relief, and to provide sufficient air supply for personnel.

5.1.1.4*Where fluid heaters are located in basements or enclosed areas, sufficient ventilation should be supplied so as to provide required combustion air and to prevent the hazardous accumulation of vapors.

5.1.1.5Fluid heaters designed for use with fuel gas having a specific gravity greater than air should be located at or above grade and should be located so as to prevent the escape of the fuel gas from accumulating in basements, pits, or other areas below the fluid heater.

5.1.1.6*Location of the fluid heater, piping, and related equipment should consider the minimum pumpable viscosity of the fluid.

5.1.2 Structural Members of the Building.5.1.2.1Fluid heaters should be located and erected so that the building structural members are not affected adversely by the maximum anticipated temperatures(see 5.1.4.3) or by the additional loading caused by the fluid heater.

5.1.2.2Structural building members should not pass through or be enclosed within a fluid heater.

5.1.3 Location in Regard to Stock, Processes, and Personnel.5.1.3.1Fluid heaters should be located so as to minimize exposure to power equipment, process equipment, and sprinkler risers.

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5.1.3.2Unrelated stock and combustible materials should be located at a distance from a fluid heater, its heating system, or ductwork so that the combustible materials will not be ignited, with a minimum separation distance of 2.5 ft (0.8 m).

5.1.3.3Adequate clearance between heat transfer fluid piping and wood or other combustible construction materials should be provided.

5.1.3.3.1A minimum 1 in. (25 mm) clearance should be provided for insulated piping withsurface temperature below 200°F (93°C).

5.1.3.3.2For insulated pipe whose surface temperature exceeds 200°F (93°C), suitableclearance to keep the surface temperature of nearby combustible constructionmaterials below 160°F (71°C) should be provided.

5.1.3.3.3A minimum 18 in. (450 mm) clearance for uninsulated piping should beprovided.

5.1.3.4Fluid heaters should be located so as to minimize exposure of people to possible injury from fire, explosion, asphyxiation, and hazardous materials and should not obstruct personnel travel to exitways.

5.1.3.5*Fluid heaters should be designed or located so as to prevent their becoming anignition source to nearby flammable vapors, gases, dusts, and mists.

5.1.3.6Equipment should be protected from corrosive external processes and environments, including fumes or materials from adjacent processes or equipment that produce corrosive conditions when introduced into the fluid heater environment.

5.1.4 Floors and Clearances.

5.1.4.1Fluid heaters should be located with space Space should be provided above and on all sides for inspection and maintenance , maintenance, andoperational purposes.

5.1.4.2In addition to the recommendation in 5.1.4.1, where applicable, adequate space should be provided for the installation of extinguishing systems and for the functioning of explosion venting.

5.1.4.3*Fluid heaters should be constructed and located to keep temperatures at combustible floors, ceilings, and walls less than 160°F (71°C).

5.1.4.4Floors in the area of mechanical pumps, liquid fuel burners, or other equipment using oil should be provided with a noncombustible, nonporous surface to prevent floors from becoming soaked with oil.

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5.1.4.5Means should be provided to prevent released fluid from flowing into adjacent areas or floors below.

5.1.5 Manifolds and External Piping.Manifolds and external piping should be located to allow access for removal oftubes.5.2* Fluid Heater Design.5.2.1Fluid heaters and related equipment should be designed to minimize the fire hazard inherent in equipment operating at elevated temperatures.

5.2.2Fluid heater components exposed simultaneously to elevated temperatures and air should be constructed of noncombustible material.

5.2.3*Fluid heater structural members should be designed to support the maximum loads of the fluid heater throughout the anticipated range of operatingconditions.

5.2.4*Fluid heaters should withstand the strains imposed by expansion and contraction, as well as static and dynamic mechanical loads and seismic, wind, and precipitation loads.

5.2.5Provision should be made for draining the fluid heater for maintenance and emergency conditions.

5.2.6Fluid heaters and related equipment should be designed and located to provide access for recommended inspection and maintenance.

5.2.6.1*Ladders, walkways, or access facilities should be provided so that equipment can be operated or accessed for testing and maintenance.

5.2.6.2Means should be provided for recommended internal inspection by maintenance and other personnel.

5.2.7Radiation shields, refractory material, and insulation should be retained or supported so they do not fall out of place under designed use and maintenance.

5.2.8External parts of fluid heaters that operate at temperatures in excess of 160°F (71°C) should be guarded by location, guard rails, shields, or insulation to prevent accidental contact by personnel.

5.2.8.1Openings or other parts of the fluid heater from which flames, hot gases, or fluids could be discharged should be located or guarded to prevent injury topersonnel.

5.2.8.2

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Where it is impractical to provide adequate shields or guards recommended by 5.2.8, warning signs or permanent floor markings visible to personnel entering the area should be provided.

5.2.9Observation ports or other visual means for observing the operation of individual burners should be provided and should be protected from damage by radiant heat.

5.2.10* Pressure Relief Devices.5.2.10.1Each section of the fluid flow path that can exceed the design pressure should be equipped with pressure relief.

5.2.10.2Pressure relief should be provided for fluid piping and tanks that can beisolated.

5.2.10.3Fluid vented from a pressure relief device should be directed to an approvedlocation.

5.2.10.3.1Vent piping should be sized for the anticipated flow of vented fluid, which can be a two-phase mixture.

5.2.10.3.2Horizontal piping in the vent line should be sloped so that liquid does notaccumulate.

5.2.10.3.3Heat tracing of the vent line should be considered for fluids having a minimum pour point above expected ambient temperatures.

5.2.11The metal frames of fluid heaters should be electrically grounded.

5.2.12Fluid heaters should be designed for relatively uniform heat flux to all heat transfer surfaces.

5.2.13Heater components should be designed to allow for thermal expansion.

5.2.14Refractory and insulation should be adequately supported by materials that are fit for the conditions.

5.2.15Fluid heater tube materials should be selected to accommodate the chosen fluid at the desired operating temperature, with sufficient protection against corrosion and erosion.

5.2.16Heater pressure vessels operating at pressures greater than 15 psi (100 kPa) should be stamped as ASME Boiler and Pressure Vessel Code Section I or ASME Section VIII Division 1 vessels.

5.2.17

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For combustible fluids, seamless tubes and fittings should be utilized.

5.2.18Tubing within the heat transfer area should have welded connections. Tubing or piping outside the heat transfer area should have either flanged or welded connections. Threaded connections can be used outside the heat transfer area for instrument connections and pressure relief valve corrections of 11⁄4 in. (32 mm) and smaller diameter only.

5.2.19Low point drains and high point vents should be accessible outside the heater.5.2.20The maximum unsupported length of tubes should be such that tube stress does not exceed one-half of the stress to produce 1 percent creep in 10,000hours.

5.2.21Tube hangers that cannot be easily inspected and replaced should be designed such that their stress does not exceed one-half of the stress to produce 1 percent creep in 10,000 hours.

5.2.22Burners should be designed to prevent flame impingement on tubes and tube supports when operating at maximum heat release.

5.2.23Fluid heaters should be designed to accommodate a specific range of fluid volume and mass and should not be operated outside those ranges.

5.2.24Fluid heaters should be designed for a specific range of fluid viscosities, densities, and velocities and should not be operated outside those ranges.

5.3* Explosion Mitigation.Explosion hazards should be mitigated through one of the following methods:

(1) Containment

(2) Explosion relief

(3) Location

(4) Explosion suppression

(5) Damage limiting construction

5.4* Ventilation and Exhaust System.5.4.1* Building Makeup Air.A quantity of makeup air should be admitted to fluid heater rooms and buildings to provide the air volume required for fluid heater safety ventilation andcombustion air.

5.4.2 Fans and Motors.5.4.2.1Electric motors that drive exhaust or recirculating fans should not be located inside the fluid heater or ductwork.

5.4.2.2

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Fluid heater recirculating and exhaust fans should be designed for the maximum heating system temperature.

5.4.3 Ductwork.5.4.3.1Ventilating and exhaust systems, where applicable, should be installed in accordance with NFPA 31, Standard for the Installation of Oil-Burning Equipment, or NFPA 54, National Fuel Gas Code, unless otherwise noted in this recommended practice.

5.4.3.2Wherever fluid heater exhaust ducts or stacks pass through combustible walls, floors, or roofs, noncombustible insulation, clearance, or both should be provided to prevent combustible surface temperatures from exceeding 160°F(71°C).

5.4.3.3*Where ducts pass through fire resistance–rated or noncombustible walls, floors, or partitions, the space around the duct should be sealed with a material that will noncombustible material to maintain the fire-resistance rating of the barrier.

5.4.3.4Ducts should be constructed entirely of sheet steel or other noncombustible material capable of meeting the intended installation and conditions of service, and the installation should be protected where subject to physical damage.

5.4.3.5*No portions of the building should be used as an integral part of the duct.

5.4.3.6*All ducts should be made tight throughout and should have no openings other than those required for the operation and maintenance of the system.5.4.3.7All ducts should be braced where required and should be supported by metal hangers or brackets.

5.4.3.8Stacks should be properly braced and should not be supported with guy wires.

5.4.3.9Hand holes for inspection or other purposes should be equipped with tight-fitting doors or covers.

5.4.3.10Exposed hot fan casings, fluid piping, and hot ducts [temperatures exceeding 160°F (71°C)] should be guarded by location, guard rails, shields, or insulation to prevent injury to personnel.

5.4.3.11

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Exhaust ducts should not discharge near openings or other air intakes where effluents can enter a building. be entrained and directed to locations creating ahazard.

5.5 Mountings and Auxiliary Equipment.5.5.1 Fluid Piping System.5.5.1.1Piping and fittings should be compatible with the fluid being used and with the system operating temperatures and pressures.

5.5.1.2For fluid piping systems that operate above 15 psig (100 kPa), piping materialsshould be in accordance with ANSI/ASME B31.1, Power Piping, or ANSI/ASME B31.3, Process Piping.

5.5.1.3*Flanged and threaded connections in the flow circuit should be minimized. In applications where fluid leakage creates a hazard, all pipe connections should be welded.

5.5.1.3.1Flange connections should be limited to pump, valve, boundary limit, spool, and equipment connections.

5.5.1.3.2Threaded connections should be limited to instruments and other miscellaneous connections less than 1 in. (25 mm).

5.5.1.4Thread sealant should be compatible with the fluid used and with the maximum operating temperature.

5.5.1.5Seal and gasket materials should be compatible with the fluid and with the operating temperature and pressure.

5.5.1.6The system design should accommodate the thermal expansion of the pipe.5.5.1.7*The system should be pneumatically tested with dry air prior to being filled withfluid.

5.5.1.8Thermal insulation used on pipes and equipment should be selected for the intended purpose and for compatibility with the fluid.

5.5.1.8.1Where there is a potential for fluid system leaks, the thermal insulation selectedshould be nonabsorbent.5.5.1.8.2Flanges, pumps, and equipment requiring routine maintenance should not beinsulated.

5.5.1.8.3

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Insulation applied to system piping and equipment should be applied only after a leakage or pressure test of the plant has been conducted.

5.5.1.8.4Insulation should be applied only after a full heating cycle.

5.5.1.9It is recommended that shielding be provided against hot fluid sprays in the event that a gasket or seal fails.

5.5.2Pipes, valves, and manifolds should be mounted so as to provide protection against damage by heat, vibration, and mechanical hazard.

5.5.3Fluid heater systems should have provisions such as motion stops, lockout devices, or other safety mechanisms to prevent injury to personnel during maintenance or inspection.

5.5.4Instrumentation and control equipment should meet the following criteria:

(1) Be located for ease of observation, adjustment, and maintenance

(2) Be protected from physical and thermal damage and other hazards

5.6 Heating Elements and Insulation.5.6.1Material for electric heating elements should be suitable for the specified range of design conditions.

5.6.2Internal electrical insulation material should be suitable for the specified range of design conditions.

5.7 Heat Baffles and Reflectors.5.7.1To prevent fluid heater damage, baffles, reflectors, and internal componentsupports should be designed to minimize warpage due to expansion andcontraction.

5.7.2To prevent fluid heater damage, baffles, reflectors, and internal componentsupports should be of heat-resistant material that minimizes sag, rupture, orcracking under normal operating limits specified by the manufacturer.

5.7.3Baffles and reflectors should be accessible and removable for the purpose of cleaning and repairing.

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Quick PrintChapter 6 Heating Systems6.1 General.6.1.1For the purposes of this chapter, the term heating system includes the heating source, the associated piping and wiring used to heat the enclosure, and the process fluid therein.

6.1.2All components of the heating system and control cabinet should be grounded.6.1.3Pilot burners should be considered burners, and all provisions of Section 6.2 or Section 6.3 should apply.

6.2 Fuel Gas–Fired Units.6.2.1* Scope.Section 6.2 applies to the following:

(1) Fluid heating systems fired with fuel gases such as the following:

(a) Natural gas

(b) Mixed gas

(c) Manufactured gas

(d) Liquefied petroleum gas (LP-Gas) in the vapor phase

(e) LP-Gas–air systems

(2) Gas-burning portions of dual-fuel or combination burners

6.2.2 General.Burners, along with associated mixing, valving, and safety controls and other auxiliary components, should be selected for the intended application, type, and pressure of the fuel gases to be used and temperatures to which they aresubjected.

6.2.3* Combustion Air.6.2.3.1The fuel-burning system design should provide a supply of clean combustion airdelivered in amounts prescribed by the fluid heater designer or burnermanufacturer across the full range of burner operation.

6.2.3.2Products of combustion should not be mixed with the combustion air supply.6.2.3.3

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Chapter 7 Commissioning, Operations, Maintenance, Inspection, and Testing7.1 Scope.Chapter 7 applies to safety systems and their application to fluid heaters.

7.2 Commissioning.7.2.1*Commissioning is recommended for all new installations or for any changes that affect the safety system.7.2.2The party responsible should ensure that all pertinent apparatus is installed andconnected in accordance with the system design.

7.2.3The party responsible should not release the fluid heater for operation before the installation and checkout of the recommended safety systems have beensuccessfully completed.

7.2.4The party responsible should ensure that any changes to the original design made during commissioning are reflected in the documentation.

7.2.5*The party responsible should ensure that set points of all safety interlocks aredocumented.

7.2.6*The party responsible should perform a test of the fire protection system to verify proper functioning of all interlocks and actuators.

7.2.7The party responsible should verify that distribution piping for the extinguishingagent is unobstructed.

7.2.8*If hazardous conditions could result from the presence of air, water, and othercontaminants, they should be removed from the fluid system prior to charging.

7.2.9*The fluid should be added to the heater system according to the heatermanufacturer’s instructions.

7.2.10*

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Initial preheating and operation of the heater should be conducted according to the heater manufacturer’s instructions.

7.2.11Minimum fluid flow should be established before the burner is operated.


7.2.12*A confirmed source of combustible gas should be provided to the inlet to the equipment isolation valve(s) (see 6.2.5.1 ) each time a combustible gas supply is placed into service or restored to service.

7.3 Training.7.3.1*The personnel responsible for operating, maintaining, and supervising the fluidheater should be thoroughly instructed and trained in their respective jobfunctions under the direction of a qualified person(s).7.3.2The personnel responsible for operating, maintaining, and supervising the fluidheater should be required to demonstrate an understanding of the equipment, its operation, and the practice of safe operating procedures in their respective job functions.

7.3.3Operating, maintenance, and supervisory personnel should receive regularly scheduled retraining and testing.

7.3.4*The training program should cover start-up, operation, shutdown, maintenance, and emergency procedures in detail.

7.3.5The training program should be kept current with changes in equipment and operating procedures, and training materials should be available for reference.

7.4 Operations.7.4.1The fluid heater should be operated in accordance with the design parameters.

7.4.2Operating instructions that include all of the following should be provided by the parties responsible for the system design:

(1) Design limits (maximum and minimum) on process parameters such as firing rate, turndown, fluid flow rates, and fluid characteristics

(2) Schematic piping and wiring diagrams and instrument configurations

(3) Startup procedures

(4) Shutdown procedures(5) Emergency procedures occasioned by loss of essential utilities, such as

electric power, instrument air, and inert gas

(6) Emergency procedures occasioned by process upsets, such as low fluid flow, excess firebox temperature, and indicators of fluid-fed fires

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(7) Maintenance procedures, including interlock and valve tightness testing

7.4.3*If the original equipment manufacturer no longer exists, the user should developinspection, testing, and maintenance procedures.

7.4.4The user should establish plant operating procedures that cover normal and emergency conditions and the use of fire protection equipment.

7.4.4.1Plant operating procedures should be directly applicable to the equipment involved and should be consistent with safety requirements and the manufacturer's recommendations.

7.4.4.2Plant operating procedures should be kept current with changes in equipment and processes.

7.4.4.3Where different modes of operation are possible, plant operating procedures should be prepared for each operating mode and for switching from one mode to another.

7.4.5Personnel should have access to operating instructions at all times.

7.4.6Plant operating procedures should prohibit the removal or disabling of safetydevices.

7.4.7*The system should be operated within the limits specified by the manufacturer of the heat transfer fluid and by the manufacturer of the heater.

7.5 Inspection, Testing, and Maintenance.7.5.1Safety devices should be maintained in accordance with the manufacturer'sinstructions.

7.5.2It should be the responsibility of the fluid heater manufacturer to provideinstructions for inspection, testing, and maintenance.

7.5.3*For recirculating fluid systems, the instructions in 7.5.2 should include instructions for inspection, testing, and maintenance of the heat transfer fluid.

7.5.3.1If indications of fluid overheating or contamination are observed, an investigation should be performed to evaluate and eliminate the cause of the overheating and contamination. The fluid should be drained from the heater andevaluated.

7.5.3.2If there are indications that the material being heated is infiltrating into the fluidloop, an investigation should be performed to identify the internal leakage point.

7.5.3.3

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If the fluid testing results indicate an unacceptable level of degradation orcontamination, the fluid should be replaced.

7.5.4It should be the responsibility of the user to establish, schedule, and enforce thefrequency and extent of the inspection, testing, and maintenance program, aswell as the corrective action to be taken.7.5.5*A test of the fire protection system to verify proper functioning of all interlocks and actuators should be performed annually.

7.5.6Fluid and fuel leaks should be repaired promptly.

7.5.7Fluid spills and releases should be cleaned promptly, and fluid-soaked insulation should be replaced.

7.5.8*Pressure relief valves should be tested in accordance with applicable codes and regulations.

7.5.9Cleaning of the inside or outside of heater tubes should not adversely affect tube integrity.

7.5.10All safety interlocks should be tested for function at least annually.

7.5.11*The set point of temperature, pressure, or flow devices used as safety interlocks should be verified at least annually.7.5.12Safety device testing should be documented at least annually.

7.5.13Explosion relief devices, if installed, should be visually inspected at least annually to ensure that they are unobstructed and properly labeled.

7.5.14Pressure relief devices should be tested at least annually to ensure that they are functioning properly.

7.5.15*Valve seat leakage testing of fuel gas safety shutoff valves should be performed in accordance with the manufacturer's instructions, and testing frequency should be Testing of fuel gas safety shutoff valve seat leakage and valve proving systems should be performed at least annually.

7.5.16Manual shutoff valves should be maintained in accordance with the manufacturer's instructions.

7.5.17*

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Lubricated manual shutoff valves should be lubricated and subsequently leak tested for valve closure at least annually.

7.5.18The temperature indication of the excess temperature controller should be verified at least annually as being accurate.

7.5.19Wherever any safety interlock is replaced, it should be tested for function.

7.5.20Wherever any temperature, pressure, or flow device used as a safety interlock is replaced, the setpoint should be verified.

7.5.21An inspection should be completed at least annually to verify that all designedsafety interlocks are present and have not been bypassed or renderedineffective.


7.5.22*Whenever combustible gas piping is placed into service or removed from service, any release of combustible gas should be vented to an approvedlocation.

7.6 Record Retention.Records of inspection, testing, and maintenance activities should be retained for a period of 1 year or until the next inspection, testing, or maintenance activity, whichever is longer.

7.7* Procedures.The user's operational and maintenance program should include procedures that apply to worker safety in accordance with all applicable regulations.

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Chapter 8 Heating System Safety Equipment and Application8.1 Scope.8.1.1Chapter 8 applies to safety equipment and its application to the fluid heater heating system.

8.1.2Section 8.3 should be applied to all safety controls included in this recommended practice.8.1.3*For the purpose of this chapter, the term heating system includes the heating source, associated piping, wiring, and controls used to heat the fluid heater and the fluid therein.

8.2 General.

8.2.1Thermal The recommendations of Chapter 8 should not apply to thermal liquidheaters with fuel input ratings less than 12,500,000 Btu/hr (3.7 MW) thatconform with ASME CSD-1, Controls and Safety Devices for Automatically Fired Boilers,and or with UL 795, Standard for Commercial-Industrial Gas Heating Equipment, meet the recommendations of Chapter 8 .

8.2.2All safety devices should meet one of the following criteria:

(1) Be listed for the service intended(2) Be approved, where listed devices are not available

(3) Be programmable controllers applied in accordance with Section 8.4

8.2.3Safety devices should be applied and installed in accordance with this recommended practice and the manufacturer's instructions.

8.2.4Electric relays should not be used as substitutes for electrical disconnects, and safety shutoff valves should not be used as substitutes for manual shutoffvalves.

8.2.5

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Chapter 9 Class F Heaters

9.1* General.9.1.1Class F heaters should be designed for relatively uniform to ensure that the required minimum fluid flow is achieved through parallel all tube passes.

9.1.1.1*Equal flow distribution When multiple parallel tube passes are used, balancedflow distribution between passes should be ensured by piping geometry or fixed flow restrictions. , such that each parallel pass maintains the minimum design flow rate, so that maximum fluid film temperatures and maximum allowable material temperatures are not exceeded.

9.1.1.2Adjustable balancing trim valves should not be used in multipass Class F heaters.

9.1.2The maximum allowable bulk fluid temperature should be determined based on the maximum allowable fluid film temperature that will prevent rapid fluid degradation. and the maximum allowable material temperature.

9.1.3*The heater manufacturer should determine the minimum flow rate, taking intoconsideration the maximum allowable bulk fluid temperature and the maximum and film fluid temperature at the design flow rate and all heat input rate rates .

9.1.4Where backflow into the heater presents a hazard, a means to prevent backflow should be provided.

9.1.5The fluid system should be designed so that fluid cannot installation of a pressure relief valve, of appropriate pressure and flow rating, should be installed if the fluid can be trapped in the heated zone.

9.1.5.1Discharge from relief valves should be handled in accordance with 9.2.2.

9.1.5.2Vent lines should be sized to handle 150 percent of the maximum anticipated flow.

9.1.6*

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The fluid system should be designed to maintain at least the minimum required fluid flow, as determined in 9.1.3 , through the heater under all operatingconditions.

9.1.7An expansion tank should be provided for all closed-loop liquid circuits.

9.1.8A hard-wired manual emergency switch at a remote location should be provided to initiate a safety shutdown of the entire fluid heater system at a remote location .

9.1.9A means of sampling for fluid contamination or degradation should be provided from the active loop.

9.2 Auxiliary Equipment.9.2.1 Pumps.9.2.1.1*Air-cooled or water-cooled pumps with mechanical seals or magnetically coupled (seal-less) pumps Pumps that are specifically designed for fluid heaterservice should be used.

9.2.1.2*The pumps should be compatible with the fluid used as well as the operatingpressures and temperatures.

9.2.1.3The system should be designed such that there is sufficient net positive suctionhead available for the pump.

9.2.1.4Positive displacement pumping systems should incorporate features to ensure that the minimum flow through the heater is maintained. means of pressurerelief.

9.2.1.5*If water-cooled pumps are used, a means of verifying cooling water flow should be provided.

9.2.1.6*Cold alignment of air- and water-cooled pumps should be done in accordance with the pump manufacturer’s recommendations prior to the pump beingstarted.

9.2.1.7*Hot alignment of air- and water-cooled pumps should be done within the first 24hours after operating temperature has been reached.

9.2.1.8Cold and hot alignment should be performed during commissioning and following pump maintenance.

9.2.1.9*Means should be provided to protect pumps from debris if required for the safe operation of the fluid heater.

9.2.2* Catch Tank. Effluent Handling.

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The All effluent from all pressure relief devices, vents from the expansion tank, and drains from the expansion tank should be directed to a closed catch tank. an approved location.

9.2.2.19.2.2.2The catch tank should have a vent to atmosphere, with the vent outlet located at an approved location outside the heater room.

9.2.2.3The vent should be adequately sized to handle 150 percent of the maximum flow from the heater relief device.

9.2.2.4If the fluid being relieved is combustible, a flame arrester should be located in the vent line.

9.2.2.5The contents should not be reused in the fluid heating system.9.2.2.6The catch tank inlets should be located to prevent siphoning of the contents back into the system.

9.2.2.7A liquid level indicator should be provided on the tank.

9.2.2.1 Gaseous Effluent.9.2.2.1.1Gaseous effluents that are asphyxiants, toxic, or corrosive are outside the scope of this recommended practice, and other standards should be consulted for appropriate venting.9.2.2.1.2Flammable gases and oxidizers should be vented to an approved location to prevent fire or explosion hazards.

9.2.2.1.3When gaseous effluents are vented, the vent pipe should be located in accordance with the following:

(1) Gaseous effluents should not impinge on equipment, support, building, windows, or materials because the gas could ignite and create a fire hazard.

(2) Gaseous effluents should not impinge on personnel at work in the area or in the vicinity of the exit of the vent pipe because the gas could ignite and create a fire hazard.

(3) Gaseous effluents should not be vented in the vicinity of air intakes, compressor inlets, or other devices that utilize ambient air.

9.2.2.1.4The vent exit should be designed in accordance with the following:

(1) The pipe exit should not be subject to physical damage or foreign matter that could block the exit.

(2) The vent pipe should be sized to minimize the pressure drop associated with length, fitting, and elbows at the maximum vent flow rate.

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(3) The vent piping should not have any shutoff valves in the line.

9.2.2.1.5If the gas is to be vented inside the building, the following additional guidance is offered:

(1) If the gaseous effluents are flammable and lighter than air, the flammable gases should be vented to a location where the gas is diluted below its LFL before coming in contact with sources of ignition.

(2) The gaseous effluents should not re-enter the work area without extreme dilution.

9.2.2.2 Liquid Phase Effluent.9.2.2.2.1*Liquid phase effluent should be directed to a containment vessel where the fluid may be reused or discarded.

9.2.2.2.2The effluent containment vessel should have a vent to atmosphere, with the vent outlet directed at an approved location.

9.2.2.2.2.1If the containment vessel vent has the potential to vent gaseous effluents, the requirements of 9.2.2.1 should apply.

9.2.2.2.2.2The vent from the effluent containment vessel should be adequately sized to handle 150 percent of the maximum anticipated flow.

9.2.2.2.3The effluent containment vessel’s inlets should be located to prevent siphoning of the contents back into the system.9.2.2.2.4Means for indicating liquid level should be provided on the effluent containment vessel.

9.2.2.2.5*The effluent containment vessel should be designed for the intended service.

9.2.3 Strainers.9.2.3.1One strainer should be placed in the suction piping of each pump.

9.2.3.2*A minimum 60 mesh stainless steel strainer element should be used.

9.2.3.3Isolation valves should be placed in the suction and discharge piping of the pump to facilitate cleaning of the strainer.

9.2.3.4A means should be provided to drain the strainer prior to cleaning.

9.2.3.5A pressure gauge should be placed between the strainer and the pump inlet to indicate strainer blockage.

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9.2.3 Valves.9.2.3.1Gate valves should be used for isolation purposes.

9.2.3.2Globe valves or wafer valves should be used for throttling purposes.

9.2.3.1Valves should be compatible with the fluid being used and the system operatingtemperatures and pressures.

9.2.3.2Where used, automatic process equipment bypass valves should fail open upon power loss.

9.2.3.2*Valves should be selected for the intended application.

9.2.4 Expansion Tanks.9.2.4.1The expansion tank should be connected to the fluid system piping upstream of the fluid pump.

9.2.4.2*The expansion tank should be compatible with the fluid being used and the system operating temperatures and pressures.

9.2.4.3*The expansion tank should be sized to accommodate the fluid expansion in the entire system.

9.2.4.4*A low level switch The expansion tank should be provided equipped with a low-level interlock .

9.2.4.4.1The low level switch should be satisfied before the pumps and the heater can be started.

9.2.4.4.2The low level switch should be interlocked to shut down the pump and heater if a low level occurs.

9.2.4.4.2.1In situations where maintaining flow is required to protect the heater due to residual heat, an emergency pump should be used to circulate fluid through an emergency cooling system.

9.2.4.4.3Indication of low-level interlock activation should be provided.

9.2.4.5An Means of draining the expansion tank drain to an approved location should be provided.

9.2.4.6

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A means for sampling for water contamination should be provided at the low point of the expansion tank. An expansion tank vent or an expansion tank pressure relief device should be provided and the effluent should be directed to an approved location, in accordance to 9.2.2 .

9.2.4.7Local or remote indication of tank level should be provided.9.2.4.8Expansion tanks should be vented to the catch tank.

9.2.4.8*An expansion tank pressurized with an inert gas should be used if any of thefollowing conditions exists exist :

(1) The tank is not the highest point in the system.(2) The tank contents can be at a temperature such that exposure of the fluid

to air would cause degradation of the fluid.

(3) The fluid manufacturer recommends use of an inert blanket.

(4) The fluid is operated above its atmospheric boiling point.

9.2.4.9All pressurized expansion tanks should be equipped with a pressure relief device piped to the catch tank.

9.2.4.9*All expansion tanks that are pressurized over a gauge pressure of 15 psi (100 kPa) should meet the requirements of ASME Boiler and Pressure Vessel Code , Section VIII Division 1.

9.2.4.10*Pressurized If pressurization of the expansion tanks tank is required due to the vapor pressure of the fluid, the expansion tank should have a blanket gas lowinert gas pressure alarm set at a value determined by the fluid supplier. above the vapor pressure of the fluid at the operating temperature.

9.2.4.11*If pressurization of the expansion tank is required due to the net positive suction head (NPSH) of the pump, the expansion tank should have a blanket gas low-pressure alarm set to satisfy the NPSH required by the pump.

9.3 Safety Devices for Class F Heaters.9.3.1 Low Fluid Flow.9.3.1.1*Means One or more interlocks should be provided to prove minimum fluid flowthrough the heater at all operating conditions.

9.3.1.2The minimum flow–proving device should be interlocked into the combustion safety circuitry.

9.3.1.3

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Means should be provided to prove minimum fluid level in the expansion tank at all operating conditions. The minimum flow–proving device should be interlocked to shut down the heater if a low flow occurs.

9.3.2 Interlocks.The combustion safety circuitry should incorporate the following interlocks:

(1) High stack temperature located upstream of the stack damper High flue gas temperature

(2) High process outlet temperature High fluid outlet temperature, measured as close as possible to exit of heating chamber

(3) Process low flow limit Minimum flow limit

(4) Low expansion tank fluid level

(5) Activation of the heater’s fire suppression system, where provided(6) Activation of an emergency stop

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Chapter 10 Class G Heaters

10.1* General. (Reserved)10.1.1Class G heaters should be designed to ensure that the required minimum fluid flow is achieved through all tube passes.

10.1.1.1*When multiple parallel tube passes are used, balanced flow distribution between passes should be ensured, such that each parallel pass maintains the minimum design flow rate, so that maximum fluid film temperatures and maximum allowable material temperatures are not exceeded.

10.1.2The maximum allowable bulk fluid temperature should be determined based on the maximum allowable fluid film temperature and the maximum allowable material temperature.

10.1.3*The heater manufacturer should determine the minimum designed flow rate, taking into consideration the maximum allowable bulk and film fluid temperature at all flow rates and heat input rates.

10.1.4Means of limiting the firing rate in accordance with the actual flow should be provided so that maximum fluid film temperature and maximum material temperature is not exceeded.


10.1.6The installation of a pressure relief valve, of appropriate pressure and flow rating, should be installed if the fluid can be trapped in the heated zone.

10.1.6.1Discharge from relief valves should be handled in accordance with 10.2.2 .


10.1.7*The fluid system should be designed to maintain at least the minimum required fluid flow (as determined in 10.1.3 ) through the heater under all operatingconditions.

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10.1.9A hard-wired manual emergency switch at a remote location should be provided to initiate a safety shutdown of the entire fluid heater system.


10.2 Auxiliary Equipment. (Reserved)10.2.1 Pumps.10.2.1.1*Pumps that are specifically designed for fluid heater service should be used.

10.2.1.2*The pumps should be compatible with the fluid used as well as the operating pressures and temperatures.10.2.1.3The system should be designed such that there is sufficient net positive suction head available for the pump.

10.2.1.4Positive displacement pumping systems should incorporate means of pressure relief.

10.2.1.5*If water-cooled pumps are used, a means of verifying cooling water flow should be provided.10.2.1.6*Cold alignment of air- and water-cooled pumps should be done in accordance with the pump manufacturer’s recommendations prior to the pump being started.

10.2.1.7*Hot alignment of air- and water-cooled pumps should be done within the first 24 hours after operating temperature has been reached.

10.2.1.8Cold and hot alignment should be performed during commissioning and following pump maintenance.10.2.1.9*Means should be provided to protect pumps from debris if required for the safe operation of the fluid heater.

10.2.2* Effluent Handling.All effluent from relief valves, vents, and drains should be directed to an approved location.

10.2.2.1 Gaseous Effluent.10.2.2.1.1

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Gaseous effluents that are asphyxiants, toxic, or corrosive are outside the scope of this recommended practice, and other standards should be consulted for appropriate venting.

10.2.2.1.2Flammable gases and oxidizers should be vented to an approved location to prevent fire or explosion hazards.10.2.2.1.3When gaseous effluents are vented, the vent pipe should be located in accordance with the following:











10.2.2.2 Liquid Phase Effluent.10.2.2.2.1*Liquid phase effluent should be directed to a containment vessel where the fluid can be reused or discarded.




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10.2.2.2.3The effluent containment vessels inlets should be located to prevent siphoning of the contents back into the system.

10.2.2.2.4Means for indicating liquid level should be provided on the effluent containment vessel.10.2.2.2.5*The effluent containment vessel should be designed for the intended service.

10.2.3 Valves.10.2.3.1Valves should be compatible with the fluid being used and the system operating temperatures and pressures.




10.2.4.3*The expansion tank should be sized to accommodate the fluid expansion in the entire system.10.2.4.4*The expansion tank should be equipped with a low-level interlock.

10.2.4.4.1The low-level interlock should be satisfied before the pumps and the heater can be started.

10.2.4.4.2The low-level interlock should shut down the pump and heater if a low level occurs.



10.2.4.5Means of draining the expansion tank to an approved location should be provided.

10.2.4.6

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An expansion tank vent or an expansion tank pressure relief device should be provided and the effluent should be directed to an approved location, in accordance with 10.2.2 .

10.2.4.7Local or remote indication of expansion tank level should be provided.

10.2.4.8*An expansion tank pressurized with an inert gas should be used if any of the following conditions exist:

(1) The tank is not the highest point in the system.

(2) The tank contents can be at a temperature such that exposure of the fluid to air would cause degradation of the fluid.

(3) The fluid manufacturer requires use of an inert blanket.(4) The fluid is operated at or above its atmospheric boiling point.


10.2.4.10*If pressurization of the expansion tank is required due to the vapor pressure of the fluid, the expansion tank should have a blanket gas low-pressure alarm set at a value above the vapor pressure of the fluid at the operating temperature.


10.3 Safety Devices for Class G Heaters. (Reserved)10.3.1 Low Fluid Flow.10.3.1.1*One or more interlocks should be provided to prove minimum fluid flow through the heater at all operating conditions.


10.3.1.3The minimum flow-proving device should be interlocked to shut down the heater if a low flow occurs.


(1) High flue gas temperature

(2) High fluid outlet temperature, measured as close as possible to exit of heating chamber

(3) Minimum flow limit

(4) Low expansion tank fluid level(5) Activation of the heater’s fire suppression system, where provided

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(6) Activation of an emergency stop

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Chapter 11 Class H Heaters

11.1* General. (Reserved)11.1.1Class H heaters should be designed to ensure that the required minimum fluid flow is achieved through all flow paths.

11.1.1.1*When multiple parallel flow paths are used, balanced flow distribution between flow paths should be ensured, such that each parallel path maintains the minimum design flow rate, so that maximum fluid film temperatures and maximum allowable material temperatures are not exceeded.

11.1.2The maximum allowable bulk fluid temperature should be determined based on the maximum allowable fluid film temperature and the maximum allowable material temperature.

11.1.3*The heater manufacturer should determine the minimum designed flow rate, taking into consideration the maximum allowable bulk and film fluid temperature at the design flow rate and all heat input rates.

11.1.4The temperature of all heat transfer surfaces in contact with the fluid should be below the temperature at which fluid degradation can occur under all operatingconditions.


11.1.6The installation of a pressure relief valve, of appropriate pressure and flow rating, should be installed if the fluid can be trapped in the heated zone.

11.1.6.1Discharge from relief valves should be handled in accordance with 11.2.2 .


11.1.7*The fluid system should be designed to maintain at least the minimum required fluid flow (as determined in 11.1.3 ) through the heater under all operatingconditions.

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11.1.9A hard-wired manual emergency switch at a remote location should be provided to initiate a safety shutdown of the entire fluid heater system.


11.2 Auxiliary Equipment. (Reserved)11.2.1 Pumps.11.2.1.1*Pumps that are specifically designed for fluid heater service should be used.

11.2.1.2*The pumps should be compatible with the fluid used as well as the operating pressures and temperatures.11.2.1.3The system should be designed such that there is sufficient net positive suction head available for the pump.

11.2.1.4Positive displacement pumping systems should incorporate means of pressure relief.

11.2.1.5*If water-cooled pumps are used, a means of verifying cooling water flow should be provided.11.2.1.6*Cold alignment of air- and water-cooled pumps should be done in accordance with the pump manufacturer’s recommendations prior to the pump being started.

11.2.1.7Hot alignment of air- and water-cooled pumps should be done within the first 24 hours after operating temperature has been reached.

11.2.1.8Cold and hot alignment should be performed during commissioning and following pump maintenance.11.2.1.9*Means should be provided to protect pumps from debris if required for the safe operation of the fluid heater.

11.2.2* Effluent Handling.All effluent from relief valves, vents, and drains should be directed to an approved location.

11.2.2.1 Gaseous Effluent.11.2.2.1.1

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Gaseous effluents that are asphyxiants, toxic, or corrosive are outside the scope of this recommended practice, and other standards should be consulted for appropriate venting.

11.2.2.1.2Flammable gases and oxidizers should be vented to an approved location to prevent fire or explosion hazards.11.2.2.1.3When gaseous effluents are vented, the vent pipe should be located in accordance with the following:











11.2.2.2 Liquid Phase Effluent.11.2.2.2.1*Liquid phase effluent should be directed to a containment vessel where the fluid can be reused or discarded.




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11.2.2.2.3The effluent containment vessel's inlets should be located to prevent siphoning of the contents back into the system.

11.2.2.2.4Means for indicating liquid level should be provided on the effluent containment vessel.11.2.2.2.5*The effluent containment vessel should be designed for the intended service.

11.2.3 Valves.11.2.3.1Valves should be compatible with the fluid being used and the system operating temperatures and pressures.




11.2.4.3*The expansion tank should be sized to accommodate the fluid expansion in the entire system.11.2.4.4*The expansion tank should be equipped with a low-level interlock.

11.2.4.4.1The low-level interlock should be satisfied before the pumps and the heater can be started.

11.2.4.4.2The low-level interlock should shut down the pump and heater if a low level occurs.



11.2.4.5Means of draining the expansion tank to an approved location should be provided.

11.2.4.6

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An expansion tank vent or an expansion tank pressure relief device should be provided and the effluent should be directed to an approved location, in accordance with 11.2.2 .

11.2.4.7Local or remote indication of expansion tank level should be provided.

11.2.4.8*An expansion tank pressurized with an inert gas should be used if any of the following conditions exist:


(2) The tank contents can be at a temperature such that exposure of the fluid to air would cause degradation of the fluid.

(3) The fluid manufacturer requires use of an inert blanket.(4) The fluid is operated at or above its atmospheric boiling point.


11.2.4.10*If pressurization of the expansion tank is required due to the vapor pressure of the fluid, the expansion tank should have a blanket gas low-pressure alarm set at a value above the vapor pressure of the fluid at the operating temperature.


11.3 Safety Devices for Class H Heaters. (Reserved)11.3.1 Low Fluid Flow.11.3.1.1*One or more interlocks should be provided to prove minimum fluid flow through the heater at all operating conditions.


11.3.1.3The minimum flow-proving device should be interlocked to shut down the heater if a low flow occurs.



(2) High fluid outlet temperature, measured as close as possible to exit of heating chamber


(4) Low expansion tank fluid level(5) Activation of the heater’s fire suppression system, where provided

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Quick PrintChapter 12 Fire Protection12.1* General.The user should determine the need for fire protection systems for fluid heaters or related equipment based on the hazards associated with the equipment.

12.1.1*Where determined to be necessary, portable, manual fixed, or automatic fixed fire protection systems should be provided.

12.1.2The fire protection system should be provided with a remotely located manualactuator.

12.1.3The fire protection system design should be submitted for approval to the authority having jurisdiction.

12.1.4*Where a sustained fluid fire is possible, fireproofing of exposed heater-supporting members is recommended.

12.1.5If a fluid fire occurs in the combustion chamber of a heater, it is recommended that the following actions be taken:

(1) Shut off the heating system fuel supply.

(2) Stop combustion air fans.

(3) Shut combustion air inlet dampers.

(4) Open outlet dampers to prevent overpressure of the firebox. Implement fail-safe damper position.

(5) Activate the discharge of extinguishing agent or use portable extinguishers at openings to the fire box.

(6) Depressurize the fluid system to reduce the flow of fluid into the firebox.

(7) To extinguish the fluid-fed fire, drain the fluid to a location where it will not create a hazard.

(8) Isolate or repair the fluid leak before restarting the heating system.

CAUTION: Where a pressurized fluid is at a temperature above its atmospheric boiling point, rapid draining can lead to flashing of the fluid and the generation of combustible vapors. An emergency cooler can be provided to cool the fluid tobelow its atmospheric boiling point.

12.1.6

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Quick PrintAnnex A Explanatory MaterialAnnex A is not a part of the recommendations of this NFPA document but is included for informational purposes only. This annex contains explanatory material, numbered to correspond with the applicable text paragraphs.

A.1.1Explosions and fires in fuel-fired and electric fluid heaters constitute a loss potential in life, property, and production. This recommended practice is a compilation of guidelines, rules, and methods applicable to the safe operation of this type of equipment.

Conditions and regulations that are not covered in this standard — such as toxic vapors, hazardous materials, noise levels, heat stress, and local, state, and federal regulations (EPA and OSHA) — should be considered in the design and operation of fluid heaters.

Most causes of failures can be traced to human error. The most significant failures include inadequate training of operators, lack of proper maintenance, and improper application of equipment. Users and designers must utilize engineering skill to bring together that proper combination of controls and training necessary for the safe operation of equipment. This recommended practice classifies fluid heaters as Class F fluid heaters.

Class F fluid heaters operate at approximately atmospheric pressure and present a potential explosion or fire hazard that could be occasioned by the overheating and/or release of flammable or combustible fluids from the tubing that carries them through the heating chamber. Class F fluid heaters operate with a relatively constant flow of fluid through the tubes, and the flowing fluid is intended to remove sufficient heat to maintain tubing walls cool enough to avoid irreversible damage that could lead to rupture. Safeguards that reduce the risk of fire or explosion associated with the use of fuel gases or fuel oils are also a major consideration for the design and operation of Class F fluid heaters.

A.1.1.3(7)For guidance on solid fuel systems, see NFPA 85, Boiler and Combustion Systems Hazards Code

A.1.3.1Because this recommended practice is based on the current state of the art, application to existing installations is not recommended. Nevertheless, users are encouraged to adopt those features that are considered applicable and reasonable for existing installations.

A.1.5

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PIs [1]

No recommended practice can guarantee the elimination of fires and explosions in fluid heaters. Technology in this area is under constant development, which is reflected in fuels, fluids, geometries, and materials. Therefore, the designer is cautioned that this recommended practice is not a design handbook and thus does not eliminate the need for an engineer or competent engineering judgment. It is the intention of this recommended practice that a designer capable of applying more complete and rigorous analysis to special or unusual problems have latitude in the development of fluid heater designs. In such cases, the designer should be responsible for demonstrating and documenting the safety and validity of the design.

A.3.2.1 Approved.The National Fire Protection Association does not approve, inspect, or certify any installations, procedures, equipment, or materials; nor does it approve orevaluate testing laboratories. In determining the acceptability of installations, procedures, equipment, or materials, the authority having jurisdiction may base acceptance on compliance with NFPA or other appropriate standards. In the absence of such standards, said authority may require evidence of proper installation, procedure, or use. The authority having jurisdiction may also refer to the listings or labeling practices of an organization that is concerned with product evaluations and is thus in a position to determine compliance with appropriate standards for the current production of listed items.

A.3.2.2 Authority Having Jurisdiction (AHJ).The phrase “authority having jurisdiction,” or its acronym AHJ, is used in NFPAdocuments in a broad manner, since jurisdictions and approval agencies vary, as do their responsibilities. Where public safety is primary, the authority havingjurisdiction may be a federal, state, local, or other regional department orindividual such as a fire chief; fire marshal; chief of a fire prevention bureau, labor department, or health department; building official; electrical inspector; or others having statutory authority. For insurance purposes, an insurance inspection department, rating bureau, or other insurance companyrepresentative may be the authority having jurisdiction. In many circumstances,the property owner or his or her designated agent assumes the role of theauthority having jurisdiction; at government installations, the commandingofficer or departmental official may be the authority having jurisdiction.


A.3.3.17 Hardwired.When the term hardwired is applied to the logic system itself, it refers to the method of using individual devices and interconnecting wiring to program and perform the logic functions without the use of software-based logic solvers.

A.3.2.4 Listed.The means for identifying listed equipment may vary for each organization concerned with product evaluation; some organizations do not recognize equipment as listed unless it is also labeled. The authority having jurisdiction should utilize the system employed by the listing organization to identify a listedproduct.

A.3.3.34.5 Proof-of-Closure Switch.A common method of effecting proof of closure is by valve seal over-travel. [86,2011]

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A.3.3.37 Valve Proving System.EN 1643, Valve Proving Systems for Automatic Shut-Off Valves for GasBurners and Gas Appliances, requires leakage to be less than 1.76 ft3/hr (50 L/hr). The definition of proof of closure in ANSI Z21.21/CSA 6.5, Automatic Valves for Gas Appliances, and FM 7400, Approval Standard for Liquid and Gas Safety Shutoff Valves, requires leakage less than 1 ft3/hr (28.32 L/hr). [86,2011]A.4.1.1.2Ladder-type schematic diagrams are recommended.

A.4.1.3.1The proximity of electrical equipment and flammable gas or liquid in an electrical enclosure or panel is a known risk and would be considered a classified area. Article 500 of NFPA 70, National Electrical Code, should beconsulted.

If the device fails, conduit-connecting devices handling flammable material might carry this material to an electrical enclosure, creating a classified area in that enclosure. Sealing of such conduits should be considered.A.4.1.3.4Unless otherwise required by the local environment, fluid heaters and the surrounding area are not classified as a hazardous (classified) location. The primary source of ignition associated with a fluid heater installation is the heating system or the materials heated. The presence of these ignition sources precludes the need for imposing requirements for wiring methods appropriate for a hazardous (classified) location. Refer to Section 3.3 of NFPA 497, Recommended Practice for the Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas, and Section 3.3 of NFPA 497, Recommended Practice for the Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas, regarding equipment with open flames or other ignition sources. In addition, fluid heaters are considered unclassified internally, since proved ventilation is provided to ensure safety.

A.4.3.2The following items are examples of compatibility issues to be studied: systemmaterials, flow rates, temperatures, pressures, venting, inerting, and fireprotection.A.5.1.1.1Hazards to be considered include spillage of molten metal, salt, or other moltenmaterial, hydraulic oil ignition, overheating and/or release of material beingheated in the fluid heater, and escape of fuel or flue gases.

A.5.1.1.4For additional information, refer to NFPA 31, Standard for the Installation of Oil-Burning Equipment; NFPA 54, National Fuel Gas Code; and NFPA 91, Standard for Exhaust Systems for Air Conveying of Vapors, Gases, Mists, and Noncombustible Particulate Solids.A.5.1.1.6Solidification of the fluid in the fluid heater and associated piping should be avoided. Consider providing insulation and heat tracing on piping and equipment where it is impractical to reliably guarantee that temperatures will not go below the minimum pumpable viscosity for an extended period of time.

A.5.1.3.5

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The hazard is particularly severe where vapors from nearby processes could flow by means of gravity to ignition sources at or near floor level. See NFPA 30, Flammable and Combustible Liquids Code; NFPA 33, Standard for Spray Application Using Flammable or Combustible Materials; and NFPA 34,Standard for Dipping, Coating, and Printing Processes Using Flammable or Combustible Liquids.A.5.1.4.3If the fluid heater is located in contact with a wood floor or other combustible floor and the operating temperature is above 160°F (71°C), one or both of thefollowing steps should be adequate to prevent surface temperatures ofcombustible floor members from exceeding 160°F (71°C):

(1) Combustible floor members should be removed and replaced with a monolithic concrete slab that extends a minimum of 3 ft (1 m) beyond the outer extremities of the fluid heater.

(2) Air channels, either naturally or mechanically ventilated, should be provided between the floor and the equipment (perpendicular to the axis of the equipment), or noncombustible insulation should be provided.

A.5.2Steam or hot water boilers should not be converted to fluid heating operation except under the guidance of the equipment manufacturer.

A.5.2.3Fluid heater design should include factors of safety so as to avoid failures when the heater is operating at maximum design loading.

A.5.2.4For fluid heaters that utilize induced draft fans, the design should account foroperation at subambient pressure and should be designed to prevent implosion.

A.5.2.6.1Ladders, walkways, and access facilities, where provided, should be designed in accordance with 29 CFR 1910.24 through 29 CFR 1910.29 and with ANSI A14.3, Safety Requirements for Fixed Ladders.

A.5.2.10Adequate coolant flow is vital to the safe operation of fluid heaters. Where flowswitches are provided to verify flow, they should be tested regularly. Othermeans, such as flow indicators, should also be considered for supplementing the function of flow switches (see A.5.2.10).

A.5.3For additional information regarding explosion protection of equipment andbuildings, see NFPA 68, Standard on Explosion Protection by Deflagration Venting, and NFPA 69, Standard on Explosion Prevention Systems.

Where explosion relief is provided, its location is a critical concern and should be close to the ignition source. Personnel considerations and proximity to other obstructions can affect the location selected for these vents. The intent of providing explosion relief in furnaces is to limit damage to the furnace and to reduce the risk of personnel injury due to explosions. To achieve those goals, relief panels and doors should be sized so that their inertia does not preclude their ability to relieve internal explosion pressures.

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CIs [1]

Damage-limiting construction could include exterior panels that are designed to become detached under the influence of internal pressure from a deflagration. In such cases, tethering the panels is vitally important to ensure dislodged panels don't cause injury or damage. NFPA 68 provides guidance for tethering doors and walls that can become dislodged in a deflagration event.

A.5.4For additional information, refer to NFPA 31, Standard for the Installation of Oil-Burning Equipment, NFPA 54, National Fuel Gas Code, and NFPA 91, Standard for Exhaust Systems for Air Conveying of Vapors, Gases, Mists, and Noncombustible Particulate Solids.

A.5.4.1Some fluid heaters rely on the air in a building or room for safety ventilation andcombustion. If the fluid heater fans must compete with other building fans (suchas building exhausts), safety and performance of the fluid heater could becompromised.When the air requirements of a building or room are being determined or reviewed for safety ventilation and combustion, provisions should be made for air being removed from the room for other purposes, such as for removal of heat, flue products, emergency generators, and other combustion equipment. Safety ventilation and combustion air must be in excess of air that is to be removed from the room for other purposes. Seasonal factors could also be relevant in cold climates, where building openings are closed during cold weather.

In the case of fluid heaters, especially those using natural draft, combustion air consistent with the requirements identified in Section 8.3 of NFPA 54, National Fuel Gas Code, should be provided.

A.5.4.3.3Ducts that pass through fire walls should be avoided.

A.5.4.3.5High temperature or corrosive gases conveyed in the duct could compromise structural members if contact occurs.

A.5.4.3.6All interior laps in the duct joints should be made in the direction of the flow.

A.5.5.1.3Threaded connections in the flow circuit typically are not used on piping greater than 1 in. (25 mm) NPT. Flanged and threaded connections are not recommended for flammable or combustible liquids due to possible leakage. Additional guidance can be found in ASME B31.3, Process Piping .

A.5.5.1.7Care should be taken that none of the fluid heater system components isoverpressurized. Hydrostatically testing with water can contaminate the systemdue to residual water in the system.

A.6.2.1

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The term ignition temperature means the lowest temperature at which a gas–air mixture will ignite and continue to burn. This condition is also referred to as the autoignition temperature. Where burners supplied with a gas–air mixture in the flammable range are heated above the autoignition temperature, flashbackscould occur. In general, such temperatures range from 870°F to 1300°F (465°C to 704°C). A much higher temperature is needed to ignite gas dependably. Thetemperature necessary is slightly higher for natural gas than for manufacturedgases, but for safety with manufactured gases, a temperature of about 1200°F(649°C) is needed, and for natural gas, a temperature of about 1400°F (760°C) is needed. Additional safety considerations should be given to dirt-laden gases,sulfur-laden gases, high-hydrogen gases, and low-Btu waste gases.

The term rate of flame propagation means the speed at which a flame progresses through a combustible gas–air mixture under the pressure, temperature, and mixture conditions existing in the combustion space, burner, or piping under consideration. (See Table A.6.2.1 and Figure A.6.2.1.)Table A.6.2.1 Properties of Typical Flammable Gases

Flammable Gas

Molecular Weight

Heating Value

(Btu/ft3)

Auto-Ignition

(°F)

LFL (% by

volume)

UFL (% by

volume)

Vapor Density (Air =

1)

Air Required to Burn 1 ft3 of

Gas (ft3)

Butane 58.0 3200 550 1.9 8.5 2.0 31.0

CO 28.0 310 1128 12.5 74.0 0.97 2.5

Hydrogen 2.0 311 932 4.0 74.2 0.07 2.5

Natural gas(high-Btu type)

18.6 1115 — 4.6 14.5 0.64 10.6

Natural gas (high-methane type)

16.2 960 — 4.0 15.0 0.56 9.0

Natural gas(high-inert type)

20.3 1000 — 3.9 14.0 0.70 9.4

Propane 44.0 2500 842 2.1 9.5 1.57 24.0

For SI units, 1 Btu = 1.055 kJ, 1 ft3 = 0.028 m3, C° = 5⁄9 (°F – 32).

Figure A.6.2.1 Ignition Velocity Curves for Typical Flammable Gases.

A.6.2.3For additional information, refer to NFPA 54, National Fuel Gas Code.

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A.6.2.3.4See A.5.4.1 for information on combustion air supply considerations.

A.6.2.4.1The valve used for remote shutoff service should be identified. If the main incoming service valve is used for this purpose, it must be understood that the valve might be owned by the local utility, which could affect access to and service of the valve. Remotely located valves used for shutting down fuel distribution systems that serve a number of users or pieces of equipment should be regularly exercised (by opening and closing several times) to verify their ability to operate when needed. Lubricated plug valves should be maintained annually, including the installation of sealant and leak testing.

A.6.2.5.2NFPA 54, National Fuel Gas Code, provides sizing methods for gas pipingsystems.

A.6.2.6.3When the fuel train is opened for service, the risk of dirt entry exists. It is notrequired that existing piping be opened for the sole purpose of the addition of a filter or strainer. It is good practice to have the sediment trap located upstream of the filter. The intent of the sediment trap is to remove larger particulates, while the intent of the filter is to remove smaller particulates. The reverse arrangement will result in additional maintenance and might result in removal of the filter element from service.

A.6.2.7.3Paragraph 6.2.7.3 covers venting of flammable and oxidizing gases only. Gases that are asphyxiants, toxic, or corrosive are outside the scope of this recommended practice, and other standards should be consulted for appropriate venting. Flammable gases and oxidizers should be vented to an approved location to prevent fire or explosion hazards. When gases are vented, the vent pipe should be located in accordance with the following:

(1) Gas should not impinge on equipment, support, building, windows, or materials because the gas could ignite and create a fire hazard.

(2) Gas should not impinge on personnel at work in the area or in the vicinity of the exit of the vent pipe because the gas could ignite and create a fire hazard.

(3) Gas should not be vented in the vicinity of air intakes, compressor inlets, or other devices that utilize ambient air.

The vent exit should be designed in accordance with the following:




If the gas is to be vented inside the building, the following additional guidance isoffered:

(1) If the gas is flammable and lighter than air, the flammable gases should be vented to a location where the gas is diluted below its LFL before coming in contact with sources of ignition.

(2) The gas should not re-enter the work area without extreme dilution.

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A.6.2.7.4See NFPA 54, National Fuel Gas Code, for exceptions to vent requirements.

Vent limiters are used to limit the escape of gas into the ambient atmosphere if a vented device (e.g., regulator, zero governor, pressure switch) requiring access to the atmosphere for operation has an internal component failure. Where a vent limiter is used, there might not be a need to vent the device to an approved location. Following are some general guidelines and principles on the use of vented devices incorporating vent limiters:

(1) The listing requirements for vent limiters are covered in ANSI Z21.18/CSA 6.3, Standard for Gas Appliance Pressure Regulators, for regulators and in UL 353, Standard for Limit Controls, for pressure switches and limit controls. ANSI Z21.18/CSA 6.3 requires a maximum allowable leakage rate of 2.5 ft3/hr (0.071 m3/hr) for natural gas and 1.0 ft3/hr (0.028 m3/hr) for LP-Gas at the device's maximum rated pressure. UL 353 allows 1.0 ft3/hr (0.028 m3/hr) for natural gas and 1.53 ft3/hr (0.043 m3/hr) for LP-Gas at the device's maximum rated pressure. Since a vent limiter can be rated less than the device itself and can be a field-installable device, a combination listed device and vent limiter should be used.

(2) Where a vent limiter is used, there should be adequate airflow through the room or enclosure in which the equipment is installed. In reality, conditions can be less ideal, and care should be exercised for the following reasons:

(a) The relative density of the gas influences its ability to disperse in air. The higher the relative density, the more difficult it is for the gas to disperse (e.g., propane will disperse more slowly than natural gas).

(b) Airflow patterns through a room or enclosure, especially in the vicinity of the gas leak, affect the ability of the air to dilute that gas. The greater the local air movement, the greater the ease with which the gas is able to disperse.

(c) The vent limiter might not prevent the formation of a localized flammable air–gas concentration for the preceding reasons.

A.6.2.7.5See A.6.2.7.4.

A.6.2.7.9NFPA 87 does not address vents between safety shutoff valves, but they are sometimes installed.

A.6.2.8.3Token relief valves only provide minimum pressure relief in cases where ambient temperatures increase the pressure inside the gas piping, which can occur during shutdown periods, or relieves a small increase of pressure due to high lockup pressures that occur during a shutdown.

A.6.2.10In the design, fabrication, and utilization of mixture piping, it should be recognized that the air–fuel gas mixture might be in the flammable range.

A.6.2.10.2(A)

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Two basic methods generally are used. One method uses a separate fire check at each burner, the other a fire check at each group of burners. The second method generally is more practical if a system consists of many closely spacedburners.

A.6.2.10.2(E)Acceptable safety blowouts are available from some manufacturers of air–fuel mixing machines. They incorporate the following components and design features:

(1) Flame arrester

(2) Blowout disk

(3) Provision for automatically shutting off the supply of air–gas mixture to the burners in the event of a flashback passing through an automatic fire check

A.6.2.12.1A burner is suitably ignited when combustion of the air–fuel mixture is established and stable at the discharge port(s) of the nozzle(s) or in the contiguous combustion tunnel.

A.6.3.1In the design and use of oil-fired units, the following should be considered:

(1) Unlike fuel gases, data on many important physical and chemical characteristics are not available for fuel oil, which, being a complex mixture of hydrocarbons, is relatively unpredictable.

(2) Fuel oil has to be vaporized prior to combustion. Heat generated by the combustion commonly is utilized for this purpose, and oil remains in the vapor phase as long as sufficient temperature is present. Under these conditions, oil vapor can be treated as fuel gas.

(3) Unlike fuel gas, oil vapor condenses into liquid when the temperature falls too low and revaporizes whenever the temperature rises to an indeterminate point. Therefore, oil in a cold furnace can lead to a hazardous condition, because, unlike fuel gas, it cannot be purged. Oil can vaporize (to become a gas) when, or because, the furnace-operating temperature is reached.

(4) Unlike water, for example, there is no known established relationship between temperature and vapor pressure for fuel oil. For purposes of comparison, a gallon of fuel oil is equivalent to 140 ft3 (4.0 m3) of natural gas; therefore, 1 oz (0.03 kg) equals approximately 1 ft3 (0.03 m3).

Additional considerations that are beyond the scope of this recommended practice should be given to other combustible liquids not specified in 6.3.1.

A.6.3.3For additional information, refer to NFPA 31, Standard for the Installation of Oil-Burning Equipment.

A.6.3.4.4A long circulating loop, consisting of a supply leg, a back-pressure regulating valve, and a return line back to the storage tank, is a means of reducing airentrainment. Manual vent valves might be needed to bleed air from the highpoints of the oil supply piping.

A.6.3.4.6

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The weight of fuel oil is always a consideration in vertical runs. When fuel oil isgoing up, pressure is lost. A gauge pressure of 100 psi (689 kPa) with a 100 ft(30.5 m) lift nets only a gauge pressure of 63 psi (434 kPa). When fuel oil isgoing down, pressure increases. A gauge pressure of 100 psi (689 kPa) with a 100 ft (30.5 m) drop nets a gauge pressure of 137 psi (945 kPa). This also occurs with fuel gas, but it usually is of no importance. However, it should never be overlooked with oils.

A.6.3.5.1(6)Lubricated plug valves require lubrication with the proper lubricant to shut off tightly. The application and type of gas used can require frequent lubrication to maintain the ability of the valve to shut off tightly when needed.

A.6.3.5.4Customarily, a filter or strainer is installed in the supply piping to protect the pump. However, this filter or strainer mesh usually is not sufficiently fine for burner and valve protection.A.6.3.5.6Under some conditions, pressure sensing on fuel oil lines downstream from feed pumps can lead to gauge failure when rapid pulsation exists. A failure of the gauge can result in fuel oil leakage. The gauge should be removed from service after initial burner start-up or after periodic burner checks. An alternative approach would be to protect the gauge during service with a pressuresnubber.

A.6.3.7.1The atomizing medium might be steam, compressed air, low pressure air, air–gas mixture, fuel gas, or other gases. Atomization also might be mechanical(mechanical atomizing tip or rotary cup).

A.6.3.9.1A burner is suitably ignited when combustion of the air–fuel mixture is established and stable at the discharge port(s) of the nozzle(s) or in the contiguous combustion tunnel.

A.7.2.1Commissioning could be required again following modification, reactivation, or relocation of the furnace.

A.7.2.5It is recommended that all system settings and parameters be documented for future maintenance and operational needs.

A.7.2.6A test involving discharge of an extinguishing agent in a sufficient amount to verify that the system is properly installed and functional is recommended. Thedischarge test can be simulated by an appropriate means. The discharge test can be omitted if damage to the equipment or surroundings would result.

A.7.2.8Using inert gas that is heated can help vaporize water trapped within thesystem.

A.7.2.9Addition of fluid should be at a low point of the piping. A small positive displacement pump is typically used to fill the fluid heater system.

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A.7.2.10Raising the temperature slowly helps prevent spalling during refractory dryout and curing, minimizes thermal stresses on the equipment, and prevents rapidvaporization of residual water in the piping.


A.7.2.12The evacuation/purging, charging, and confirmation of the fuel or combustible gas supply in the piping upstream of the equipment isolation valve is goverend by other codes, standards, and recommended practices. Examples are NFPA 54 , National Fuel Gas Code , which requires charging to be stopped upon detection of combustible gas at the point of discharge, and NFPA 56PS ,Standard for Fire and Explosion Prevention During Cleaning and Purging of Flammable Gas Piping Systems . Careful consideration should be given to the potential hazards that can be created in the surrounding area for any fuel or combustible gas discharge.

In NFPA 54 , the term Appliance Shutoff Valve is analogous to the term Equipment Isolation Valve in NFPA 86 and 87.

A.7.3.1The training program can include one or more of the following components:

(1) Review of operating and maintenance information

(2) Periodic formal instruction

(3) Use of simulators

(4) Field training

(5) Other procedures

(6) Comprehension testing

The following training topics should be considered for inclusion in the training program:

(1) Process and equipment inspection testing(2) Combustion of fuel–air mixtures

(3) Explosion hazards, including improper purge timing and purge flow, and safety ventilation

(4) Sources of ignition, including autoignition (e.g., by incandescent surfaces)

(5) Functions of controls, safety devices, and maintenance of proper set points

(6) Handling and processing of hazardous materials

(7) Management of process fluid level, flow, and temperature

(8) Confined space entry procedures(9) Operating instructions (see 7.4.2)

(10) Lockout/tagout procedures

(11) Hazardous conditions resulting from interaction with surrounding processes

(12) Fire protection systems

(13) Molten material

A.7.3.4

Page 11 of 33


Training should include recognition of upset conditions that could lead to dangerous conditions. Operator training should cover the relationships between firing rate, fluid flow rate, and fluid temperature increase, so that if a high fluidtemperature is detected, the cause can be determined quickly.

A.7.4.3See Annex B.A.7.4.7If a new operating envelope is desired, the equipment manufacturer and the fluid supplier should be contacted to establish new operating limits.

A.7.5.3The fluid manufacturer should be consulted for help in determining where in thesystem to take samples. The samples should be sent to the supplier. Facilitieswith laboratories might be able to perform independent tests, provided abaseline sample is available for comparison purposes.

A.7.5.5Tests involving the discharge of the extinguishing agent should be performed at a frequency recommended by the fire protection system manufacturer.

A.7.5.8See, for example, the NBBPVI National Board Inspection Code.

A.7.5.11In cases where minimal operating states (e.g., minimum fluid flow) must be established to prevent a hazardous condition, it is recommended that the precision of the set point be confirmed. Where precision is inadequate, the component should be either recalibrated or replaced. Frequency of this testing and calibration should be established based on the component’s mean time between failure (MTBF) data and the component manufacturer’srecommendations.

A.7.5.15An example of a leak test procedure for safety shutoff valves on direct gas-firedovens with a self-piloted burner and intermittent pilot follows.

Leak Test Procedure. With the oven burner(s) shut off, the main shutoff valve open, and the manual shutoff valve closed, proceed as follows:

(1) Place the tube in test connection 1 and immerse it just below the surface of a container of water.

(2) Open the test connection valve. If bubbles appear, the valve is leaking; reference the manufacturer’s instructions for corrective action. The auxiliary power supply to safety shutoff valve No. 1 should be energized, and the valve should be opened.

(3) Place the tube in test connection 2 and immerse it just below the surface of a container of water.

(4) Open the test connection valve. If bubbles appear, the valve is leaking. Reference the manufacturer’s instructions for corrective action.

The preceding procedure is predicated on the piping diagram shown in FigureA.7.5.15(a) and the wiring diagram shown in Figure A.7.5.15(b).

Page 12 of 33


It is recognized that safety shutoff valves are not entirely leakfree. Valve seats can deteriorate over time and require periodic leak testing. Many variables are associated with the valve seat leak testing process, including gas piping and valve size, gas pressure and specific gravity, size of the burner chamber, length of downtime, and the many leakage rates published by recognized laboratories and other organizations.Leakage rates are published for new valves and vary by manufacturer and the individual listings to which the manufacturer subscribes. It is not expected that valves in service can be held to published leakage rates, but rather that the leakage rates are comparable over a series of tests over time. Any significant deviation from the comparable leakage rates over time will indicate to the user that successive leakage tests can indicate unsafe conditions. These conditions should then be addressed by the user in a timely manner.

The location of the manual shutoff valve downstream of the safety shutoff valve affects the volume downstream of the safety shutoff valve and is an important factor in determining when to start counting bubbles during a safety shutoff valve seat leakage test. The greater the volume downstream of the safety shutoff valve, the longer it will take to fully charge the trapped volume in the pipe between the safety shutoff valve and the manual shutoff valve. This trapped volume needs to be fully charged before starting the leak test.

Care should be exercised during the safety shutoff valve seat leakage test, because flammable gases will be released into the local environment at some indeterminate pressure. Particular attention should be paid to lubricated plug valves if used as manual shutoff valves, in order to ensure that they have been properly serviced prior to the valve seat leakage test.Examples, although not all-inclusive, of acceptable leakage rate methodologies that the user can employ can be found in the publications in Annex D.

Figure A.7.5.15(a) through Figure A.7.5.15(c) show examples of gas piping and wiring diagrams for leak testing.

The following example also is predicated on the piping diagram shown in Figure A.7.5.15(a) and the wiring diagram shown in Figure A.7.5.15(b).

With the burner(s) shut off, the equipment isolation valve open, and the manual shutoff valve located downstream of the second safety shutoff valve closed, proceed as follows:

(1) Connect the tube to leak test valve No. 1.

(2) Bleed trapped gas by opening leak test valve No. 1.

(3) Immerse the tube in water as shown in Figure A.7.5.15(c). If bubbles appear, the valve is leaking — reference the manufacturer’s instructions for corrective action. Examples of acceptable leakage rates are given in Table A.7.5.15.

(4) Apply auxiliary power to safety shutoff valve No. 1. Close leak test valve No. 1. Connect the tube to leak test valve No. 2 and immerse it in water as shown in Figure A.7.5.15(c).

(5) Open leak test valve No. 2. If bubbles appear, the valve is leaking —reference the manufacturer’s instructions for corrective action. Examples of acceptable leakage rates are given in Table A.7.5.15.

[86:A.7.4.9(1)–A.7.4.9(5)]Figure A.7.5.15(a) Example of a Gas Piping Diagram for Leak Test. [86:Figure A.7.4.9(a)]

Page 13 of 33



Figure A.7.5.15(b) Example of a Wiring Diagram for Leak Test. [86:Figure A.7.4.9(b)]

Figure A.7.5.15(c) Leak Test for a Safety Shutoff Valve. [86:Figure A.7.4.9(c)]

Table A.7.5.15 Acceptable Leakage Rates

NPT Nominal

Size(in.)

DN Nominal

Size (mm)

UL 429, ANSI Z21.21/CSA 6.5 FM 7400

ft3/hrmL/hr cc/hr

mL/min cc/min

Bubbles/ min ft3/hr

mL/hrcc/hr

mL/min cc/min

Bubbles/ min

0.38 10 0.0083 235 3.92 26 0.014 400 6.7 44

0.50 15 0.0083 235 3.92 26 0.014 400 6.7 44

0.75 20 0.0083 235 3.92 26 0.014 400 6.7 441.00 25 0.0083 235 3.92 26 0.014 400 6.7 44

1.25 32 0.0083 235 3.92 26 0.014 400 6.7 44

1.50 40 0.0124 353 5.88 39 0.014 400 6.7 44

2.00 50 0.0166 470 7.83 52 0.014 400 6.7 44

2.50 65 0.0207 588 9.79 65 0.014 400 6.7 44

3.00 80 0.0249 705 11.75 78 0.014 400 6.7 44

4.00 100 0.0332 940 15.67 104 0.014 400 6.7 44

6.00 150 0.0498 1410 23.50 157 0.014 400 6.7 448.00 200 0.0664 1880 31.33 209 0.014 400 6.7 44

[86: Table A.7.4.9]

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A.7.5.17Lubricated plug valves require lubrication with the proper lubricant in order to shut off tightly. The application and type of gas used can require frequent lubrication to maintain the ability of the valve to shut off tightly when needed.


A.7.5.22See A.6.2.7.3 .

A.7.7Examples of worker safety procedures and regulations can be found in ANSI Z117.1, Safety Requirements for Confined Spaces; NIOSHPocket Guide to Chemical Hazards; 29 CFR, Chapter XVII, Occupational Safety and Health Administration, Department of Labor, and other references.

A.8.1.3For the protection of personnel and property, consideration should also be given to the supervision and monitoring of conditions in systems other than the heating system that could cause or that could lead to a potential hazard on anyinstallation.

A.8.2.9For some applications, additional manual action might be required to bring the process to a safe condition. The actions resulting from a manual emergency switch action take into account the individual system design and the hazards (e.g., mechanical, combustion system, process fluid, thermal fluid, etc.) associated with changing the existing state to another state and initiates actions to cause the system to revert to a safe condition.

A.8.3Furnace controls Fluid heater controls that meet the performance-based requirements of standards such as ANSI/ISA 84.00.01, Application of Safety Instrumented Systems for the Process Industries, or IEC 61511, FunctionalSafety: Safety Instruments Systems for the Process Industry Sector , can be considered equivalent. The determination of equivalency involves complete conformance to the safety life cycle, including risk analysis, safety integrity levelselection, and safety integrity level verification, which should be submitted tothe authority having jurisdiction.

A.8.3.1.4This control circuit and its non-furnace-mounted or furnace-mounted control and safety components should be housed in a dusttight panel or cabinet, protected by partitions or secondary barriers, or separated by sufficient spacing from electrical controls employed in the higher voltage furnace power system. Related instruments might or might not be installed in the same control cabinet. The door providing access to this control enclosure might include means formechanical interlock with the main disconnect device required in the furnacepower supply circuit.

Temperatures within this control enclosure should be limited to 125°F (52°C) for suitable operation of plastic components, thermal elements, fuses, and various mechanisms that are employed in the control circuit.

Page 15 of 33





A.8.4One PLC approach to combustion interlocks on multiburner heating systems is as follows:

(1) Interlocks relating to purge are done via the PLC.

(2) Purge timer is implemented in the PLC.(3) Interlocks relating to combustion air and gas pressure are done via the

PLC.

(4) Gas valves for pilot and burner directly connected to combustion safeguard should conform to the recommendations of 8.7.2.

(5) Operation of pilot and burner gas valves should be confirmed by the PLC.

(6) A PLC can be set up as intermittent, interrupted, or constant pilot operation. With appropriate flame safeguard, it would be possible to provide an interrupted pilot with one flame sensor and one flamesafeguard.


A.8.4.4.1This recommended practice suggests that the signal from the safety device be directly transmitted to the safety PLC input. Once the safety PLC processes the signal the resulting data can be used for any purpose.

A.8.5.1.2(1)Sampling in more than one location could be necessary to adequately confirm the absence of combustible vapors or gas in the heating chambers and all the passages that contain the products of combustion.


A.8.5.1.2.1(2)Consideration should be given to the proximity of operating burners when the common combustion chamber exception to repeating purges is utilized. Accumulation of localized vapors or atmospheres is possible even with an operating burner in a chamber, depending on the size of the chamber, the number of burners, and the proximity of operating burners to the accumulation. In addition to proximity, burner design and exposure of the flame can also impact the ability of the operating burner to mitigate vapor or gaseous accumulations.

A.8.5.2When the purge is complete, there should be a limit to the time between the completed purge and the trial for ignition. Delay can result in the need for arepurge.

A.8.6.5Interlocks for combustion air minimum pressure or flow can be provided by any of the following methods:

Page 16 of 33



(1) A low-pressure switch that senses and monitors the combustion air source pressure. In industrial combustion applications with modulating flow control valves downstream of the combustion air blower, it is most common to interlock the constant combustion air source pressure onsingle-burner and multiburner systems to meet the recommendations of8.6.3 and 8.6.5 . Because the combustion airflow is proved during each purge cycle along with the combustion air source pressure, the most common convention is to prove the combustion air source pressure during burner operation following purge. In a multiburner system, the proof of combustion airflow during purge proves that any manual valves in the combustion air system are in an adequately open position. These manual air valves are provided for maintenance and combustion airflow balancing among burners in a temperature control zone. In combustionair supply systems that use either an inlet damper or a speed control, thecombustion air pressure can fall below reliably repeatable levels with listed pressure switch interlocks at low fire. For these systems, the proof of minimum airflow can be a more reliable interlock.

(2) A differential pressure switch that senses the differential pressure across a fixed orifice in the combustion air system. In combustion air supply systems that use either an inlet damper or a speed control, the combustion air pressure can fall below reliably repeatable levels with listed pressure switch interlocks at low fire. For these systems, the proof of minimum airflow by use of a differential pressure switch across anorifice can be a more reliable interlock.

(3) An airflow switch. In combustion air supply systems that use either an inlet damper or a speed control, the combustion air pressure can fall below reliably repeatable levels with listed pressure switch interlocks at low fire. For these systems, the proof of minimum airflow by use of an airflow switch can be a more reliable interlock.

(4) A pressure switch on the inlet (suction) side of an induced draft (I.D.) fan.For heaters where airflow is induced by an I.D. fan, a pressure switch on the inlet of the I.D. fan can be used to prove that the minimum required suction pressure is available, which along with proof that air and stack dampers are not closed can be used as a minimum air flow interlock.

(5) For combustion systems that use high pressure gas/air to induce (inspirate) air locally at each burner or that use natural draft to induce air into the burners or combustion champer, proof that air and stack dampers are not closed/open to at least a minimum position can be used to satisfy the intent of a low air flow interlock. It is not possible to monitor and prove the availability of combustion air for fluid heaters that use natural draft or air inspiriting burners.

A.8.6.6Where compressed air is utilized, the maximum safe operating pressure can beexceeded.

A.8.7.1.2See Figure A.8.7.1.2.

Figure A.8.7.1.2 Multiple Burner System Using Proof-of-Closure Switches.

Page 17 of 33



A.8.7.1.3Paragraph 8.7.1.3 addresses conditions under which only one safety shutoff valve is to close to isolate a burner from its fuel gas supply. Figure A.8.7.1.3provides a summary of 8.7.1.3 in the form of a decision tree. See 8.5.1.1.2for guidance regarding conditions that are needed to allow that burner to be placed back in service. The requirements of 8.5.1.1.2 might not allow a burner shut off by closing a single safety shutoff valve to be placed back in service without repeating a pre-ignition purge.

The requirements of 8.7.1.3 do not preclude opening of the safety shutoff valve located upstream of the individual burners using single safety shutoff valves during the trial for ignition for the first burner being lighted.

Figure A.8.7.1.3 Safety Shutoff Decision Tree

Page 18 of 33


PIs [1]

PIs [1]


A.8.7.1.9Backpressure can lift a valve from its seat, permitting combustion gases to enter the fuel system. Examples of situations that create backpressure conditions are leak testing, combustion chamber back pressure, and combustion air pressure during prepurge.

A.8.7.1.10See A.6.2.7.3.

A.8.7.2See Figure A.8.7.2.

Figure A.8.7.2 Typical Piping Arrangement Showing Fuel Gas Safety Shutoff Valves.

A.8.7.2.2An additional safety shutoff valve located to be common to the heating system and that is proved closed and interlocked with the pre-ignition purge circuit can be used to meet the recommendations of 8.7.2.2.

A.8.7.3.3An additional safety shutoff valve that is located so as to be common to theheating system and that is proved closed and interlocked with the pre-ignitionpurge circuit can be used to meet the recommendations of 8.7.3.2.

A.8.9.2Ultraviolet detectors can fail in such a manner that the loss of flame is not detected. When these detectors are placed in continuous service, failures can be detected by use of a self-checking ultraviolet detector or by periodic testing of the detector for proper operation.

Flame detectors (scanners) with combustion safeguards that continuously operate beyond the maximum interval recommended by the combustion safeguard and flame detector manufacturer's instructions would not becompliant.A.8.9.2(3)The term self-piloted burner is defined in NFPA 86, Standard for Ovens andFurnaces, 3.3.5.14.

A.8.11

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Some liquid fuel can become too viscous for proper atomization at low temperatures. Some liquid fuels can congeal if their temperature falls below their pour point. Some liquid fuels can vaporize at higher temperatures and negatively affect burner stability.

A.8.12.1The fact that oil or gas is considered a standby fuel should not reduce the safety requirements for that fuel.

A.8.15The fluid should be protected with an additional temperature limit interlock toprevent excess fluid temperatures.

A.8.15.4Temperature-sensing components, such as thermocouple and extension wires, that are not rated for the environment are at greater risk of short-circuiting.

A.8.17.1.1Abnormal conditions that could occur and require automatic or manual de-energization of affected circuits are as follows:

(1) A system fault (short circuit) not cleared by normally provided branch-circuit protection (see NFPA 70, National Electrical Code)

(2) The occurrence of excess temperature in a portion of the furnace that has not been abated by normal temperature-controlling devices

(3) A failure of any normal operating controls where such failure can contribute to unsafe conditions

(4) A loss of electric power that can contribute to unsafe conditions

A.8.17.1.5The permitted use in 8.17.1.5 could necessitate the derating of some components listed by manufacturers for other types of industrial service and motor control and as shown in Table A.8.17.1.5.

Table A.8.17.1.5 Heater Ratings

Control Device

Resistance-Type Heating Devices

Infrared Lamp and Quartz Tube Heaters

Rating (%

actual load)

Permissible Current

(% rating)

Rating (%

actual load)

Permissible Current

(% rating)Fusible safety switch (% rating of fuseemployed)

125 80 133 75

Individually enclosed circuit breaker 125 80 125 80

Circuit breakers in enclosed panelboards

133 75 133 75

Magnetic contactors

0–30 amperes 111 90 200 50

30–100 amperes 111 90 167 60

150–600 amperes 111 90 125 80

Page 20 of 33





Note: This table applies to maximum load or open ratings for safety switches, circuit breakers, and industrial controls approved under current National Electrical Manufacturers Association (NEMA) standards.

A.8.17.2The excess temperature set point should be set no higher than the maximum element temperature specified by the element manufacturer. The fluid should be protected with an additional temperature limit controller to prevent excess fluid temperatures.

A.8.17.2.5Temperature-sensing components, such as thermocouple and extension wires, that are not rated for the environment are at greater risk of short-circuiting.

A.8.17.2.6The sensing element should be positioned where the difference between thetemperature control sensor and the excess temperature limit sensor is minimized. The temperature-sensing element of the excess temperature limit interlock should be located where it will sense the excess temperature condition that will cause the first damage to the heating element.

A.9.1Class F heaters have fluid inside the tubes with essentially constant fluid flow rate and where the outlet temperature of the fluid is controlled by modulation of the heat input rate to the outside of the tubes. A fluid bypass loop should beconsidered to achieve variable flow to the user.

Class F fluid heaters present the following two major hazards:

(1) Uncontrolled release of the fluid, which can cause be caused by tube cracking or rupture, or pump seal failure, fire, which can result in fire orexplosion

(2) Combustible Release and accumulation of combustible fuel gas or liquid, followed by ignition and explosion

A.9.1.1.1Balanced flow is typically achieved by the piping geometry or fixed flow restrictions. If fluid flow rates fall below the designed minimum flow rate, fluid overheating and subsequent degradation can occur. Some heater designs have one flow rate for tubes in the radiant section and another flow rate for tubes in the convective section.

If balancing trim valves are used, the flow through each pass should be monitored and interlocked into the combustion safety circuitry. Manual balancing trim valves should also have provisions to lock the valve to prevent inadvertent adjustment of the valve.

A.9.1.3The maximum bulk fluid temperature is typically measured at the outlet of the heater.


Page 21 of 33






A.9.1.5The installation of a pressure relief valve between the blocking valves or of a block valve at the inlet to the heater and a check valve at the outlet can beused.

A.9.1.6Three-way valves or an automatic process equipment bypass can be used to maintain the minimum flow through the heater.

A.9.2.1.1Air-cooled or water-cooled pumps with mechanical seals, canned motor pumps, seal-less pumps, and pumps that are magnetically coupled are examples of pumps that are used. If magnetically coupled pumps are used, over-temperature protection of the pump coupling location should be provided.Packing-based seals are prone to leakage and are not recommended. The pump material selection should take into account the possible thermal shock experienced under fire suppression scenarios.

A.9.2.1.2The fluid manufacturer and the heater manufacturer the person or company responsible for the design or supply of the fluid heater should be consulted to provide recommendations on the appropriate pump for the application.A.9.2.1.5Loss of cooling can cause seal failure and a subsequent fire hazard.

A.9.2.1.6Misalignment can cause seal failure and a subsequent fire hazard.

A.9.2.1.7The alignment of the pump can change during the transition from cold to operating temperatures.

A.9.2.1.9Examples of devices to protect pumps can be drip legs, strainers, filters, and screens.


A.9.2.2If the fluid being relieved is combustible, measures should be taken to prevent ignition of the vapors or aerosols from the vent. Additional guidance can be found in NFPA 30 , Flammable and Combustible Liquids Code .

A.9.2.2.2.1Containment vessels for liquids include drain tanks, fill tanks, supplemental storage tanks, and catch tanks.


Page 22 of 33










A.9.2.3.2Refer to the pump manufacturer’s manual for additional instructions.

A.9.2.4.3Cast steel or ductile iron valves with steel or stainless steel trim are typically used.

A.9.2.2.2.5Secondary containment of effluent containment vessel should be considered if the fluid is flammable or hazardous.

A.9.2.3.2Gate and ball valves can be used for isolation purposes, and globe or wafer-style butterfly valves can be used for throttling purposes.

A.9.2.4.2Expansion tanks are typically fabricated from carbon and stainless steel.

A.9.2.4.3Expansion tanks are typically 2.5 times the expansion volume of the system. The operating temperature, the expansion coefficient of the fluid, and the system volume are used to calculate this value the volume of the expansion tank . Some vapor space should remain in the tank when the system is at operating temperature. If the tank is located outdoors, an inert blanket should be considered to minimize moisture ingress into the system. For very large systems, where expansion tanks are elevated and working volume exceeds 1000 gallons, a secondary, ground-level catch/storage tank and refill pumps can be used to take up excess expansion volume.

A.9.2.4.4In addition to the low-level interlock, on large volume systems, it is good practice to use dynamic leak detection (rate of change monitoring) on expansion tanks. Dynamic leak detection is encouraged because it will detect abnormal fluid loss over time whereas a low-level switch is a single set point and often located just above tank empty. In some situations, expansion tanks can be several thousand gallons in capacity. Therefore, if only low-levelmonitoring is provided, several thousand gallons could escape the system before the alarm is sounded. With dynamic leak detection, alarm notification of the falling oil level will be made much sooner.

Page 23 of 33







A.9.2.4.8Nitrogen is typically used as the inert blanket. Other gases, such as carbon dioxide, can be used. In the oil and gas industry it is common to use flammable gases. If using flammable gases, other precautions should be considered, such as area classification and explosion-proof electrical devices.

A.9.2.4.9Consideration should be given to pressure surges that can occur during process upsets that can expose the expansion tank to pressures greater than 15 psi. An example of a common process upset is the rapid pressure rise due to water flashing to steam. For this reason, many users specify expansion tanks to meet the requirements of ASME Boiler and Pressure Vessel Code , Section VIII Division 1.

A.9.2.4.10A blanket gas low-pressure interlock should be considered where low blanket gas pressure could create a fluid heater system hazard.

A.9.2.4.11See A.9.2.4.10 .

A.9.3.1.1The required minimum fluid flow rate is based on design requirements. Detecting only flow/no flow conditions might be inadequate is not adequate . Apressure switch at the pump discharge, and a pump rotation switch, and a flow paddle switch are examples of proving devices that are not recommended to prove minimum flow as unexpected blockages in the heater tubes will not be detected by these devices . For example, restriction of flow will result in an increase in the fluid outlet temperature, which in turn will drive a reduction in heat input (low fire). Low flow rates under this condition could cause laminar flow in the tubes, resulting in undetected localized fluid skin overtemperature conditions. Using a vortex-shedding meter or similar flow measurement device can provide reliable minimum flow verification. However, a failure modes and effects analysis should be conducted to ensure that the implementation is sufficiently reliable for a safety function implementation. Another option is to use a combination of pressure differential measurements across a known restriction combined with low and high pressure limits. The high pressure limits will detect blockage or other abnormal flow restrictions that maintain high differential pressures at low flow conditions. Conversely, low pressure limits can detect system leaks or bypass flows.

Orifice plate(s) located at the outlet of a fluid heater and used with differential pressure interlock(s) are a reliable way of proving the minimum flow. If pressure drop across the heater is used, additional interlocks and precautions should be considered.

A.10.1

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Class G heaters have fluid inside the tubes with modulated fluid flow rate (e.g., by process demand) and where the outlet temperature of the fluid is controlled by modulation of the heat input rate to the outside of the tubes.

Class G fluid heaters present the following two major hazards:

(1) Uncontrolled release of the fluid, which can cause tube cracking or rupture, pump seal failure, fire, or explosion which can result in fire or explosion

(2) Combustible accumulation and explosion Release and accumulation ofcombustible fuel gas or liquid, followed by ignition and explosion

A.10.1.1.1Balanced flow is typically achieved by the piping geometry or fixed flow restrictions. If fluid flow rates fall below the designed minimum flow rate, fluid overheating and subsequent degradation can occur. Some heater designs have one flow rate for tubes in the radiant section and another flow rate for tubes in the convective section.



A.10.1.7The fluid flow control device should have mechanical stops or equivalent provisions to prevent the flow from dropping below the minimum design flow. Variable speed pumping systems should provide a minimum motor speed limit to prevent flow less than the minimum required level in both automatic and manual operation.

A.10.2.1.1Air-cooled or water-cooled pumps with mechanical seals, canned motor pumps, seal-less pumps, and pumps that are magnetically coupled areexamples of pumps that are used. If magnetically coupled pumps are used,over-temperature protection of the pump coupling location should be provided.Packing-based seals are prone to leakage and are not recommended. The pump material selection should take into account the possible thermal shockexperienced under fire suppression scenarios.

A.10.2.1.2The fluid manufacturer and the heater manufacturer should be consulted to provide recommendations on the appropriate pump for the application.

Page 25 of 33












A.10.2.1.5Loss of cooling can cause seal failure and a subsequent fire hazard.




A.10.2.2If the fluid being relieved is combustible, measures should be taken to prevent ignition of the vapors or aerosols from the vent. Additional guidance can be found in NFPA 30 , Flammable and Combustible Liquids Code .





A.10.2.4.3

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The operating temperature, the expansion coefficient of the fluid, and the system volume are used to calculate the volume of the expansion tank. Some vapor space should remain in the tank when the system is at operating temperature. If the tank operates at atmospheric pressure and is located outdoors, an inert gas blanket should be considered to minimize moistureingress into the system. For very large systems, where expansion tanks areelevated and working volume exceeds 1000 gallons, a secondary, ground-level catch/storage tank and refill pumps can be used to take up excess expansion volume.

A.10.2.4.4In addition to the low-level interlock, on large-volume systems, it is good practice to use dynamic leak detection (rate of change monitoring) on expansion tanks. Dynamic leak detection is encouraged because it will detect abnormal fluid loss over time whereas a low-level switch is a single set point and often located just above tank empty. In some situations, expansion tanks can be several thousand gallons in capacity. Therefore, if only low-levelmonitoring is provided, several thousand gallons could escape the system before the alarm is sounded. With dynamic leak detection, alarm notification of the falling oil level will be made much sooner.

A.10.2.4.8Nitrogen is typically used as the inert blanket. Other gases, such as carbon dioxide, can be used. In the oil and gas industry it is common to use flammable gases. If using flammable gases, other precautions can be required, such as area classification and explosion-proof electrical devices.

A.10.2.4.9Consideration should be given to pressure surges that can occur during process upsets that can expose the expansion tank to pressures greater than 15 psi. An example of a common process upset is the rapid pressure rise due to water flashing to steam. For this reason, many users specify expansion tanks that meet the requirements of ASME Boiler and Pressure Vessel Code , Section VIII Division 1.

A.10.2.4.10A blanket gas low-pressure interlock should be considered where low blanket gas pressure can create a fluid heater system hazard.

A.10.2.4.11See A.10.2.4.10 .

A.10.3.1.1

Page 27 of 33







Detecting only flow/no flow conditions is not adequate. A pressure switch at the pump discharge and a pump rotation switch are examples of proving devices that are not recommended to prove minimum flow as unexpectedblockages in the heater tubes will not be detected by these devices.


A.11.1Class H heaters have heat source (combustion or electricity) inside the tube(s) with fluid surrounding the tube.

Class H fluid heaters present the following two major hazards:

(1) Uncontrolled release of the fluid, which can cause tube cracking or rupture, or pump seal failure, fire, or explosion which can result in fire orexplosion

(2) Combustible accumulation and explosion Release and accumulation of combustible fuel gas or liquid, followed by ignition and explosion

A.11.1.1.1Balanced flow is typically achieved by the piping geometry or fixed flow restrictions. If fluid flow rates fall below the designed minimum flow rate, fluid overheating and subsequent degradation can occur.



A.11.1.7Three-way valves or an automatic process equipment bypass can be used to maintain the minimum flow through the heater.

A.11.2.1.1Air-cooled or water-cooled pumps with mechanical seals, canned motor pumps, seal-less pumps, and pumps that are magnetically coupled areexamples of pumps that are used. If magnetically coupled pumps are used,over-temperature protection of the pump coupling location should be provided.Packing-based seals are prone to leakage and are not recommended. The pump material selection should take into account the possible thermal shockexperienced under fire suppression scenarios.

Page 28 of 33












A.11.2.1.2The fluid manufacturer and the heater manufacturer should be consulted to provide recommendations on the appropriate pump for the application.

A.11.2.1.5Loss of cooling can cause seal failure and a subsequent fire hazard.




A.11.2.2If the fluid being relieved is combustible, measures should be taken to prevent ignition of the vapors or aerosols from the vent. Additional guidance can be found in NFPA 30, Flammable and Combustible Liquids Code .




Page 29 of 33









A.11.2.4.3The operating temperature, the expansion coefficient of the fluid, and the system volume are used to calculate the volume of the expansion tank. Some vapor space should remain in the tank when the system is at operating temperature. If the tank operates at atmospheric pressure and is located outdoors, an inert gas blanket should be considered to minimize moistureingress into the system. For very large systems, where expansion tanks areelevated and working volume exceeds 1000 gallons, a secondary, ground-level catch/storage tank and refill pumps can be used to take up excess expansion volume.

A.11.2.4.4In addition to the low-level interlock, on large-volume systems, it is good practice to use dynamic leak detection (rate of change monitoring) on expansion tanks. Dynamic leak detection is encouraged because it will detect abnormal fluid loss over time whereas a low-level switch is a single set point and often located just above tank empty. In some situations, expansion tanks can be several thousand gallons in capacity. Therefore, if only low-levelmonitoring is provided, several thousand gallons could escape the system before the alarm is sounded. With dynamic leak detection, alarm notification of the falling oil level will be made much sooner.

A.11.2.4.8Nitrogen is typically used as the inert blanket. Other gases, such as carbon dioxide, may be used. In the oil and gas industry it is common to use flammable gases. If using flammable gases, other precautions can be required, such as area classification and explosion-proof electrical devices.

A.11.2.4.9Consideration should be given to pressure surges that can occur during process upsets that can expose the expansion tank to pressures greater than 15 psi. An example of a common process upset is the rapid pressure rise due to water flashing to steam. For this reason, many users specify expansion tanks that meet the requirements of ASME Boiler and Pressure Vessel Code , Section VIII Division 1.

A.11.2.4.10A blanket gas low-pressure interlock should be considered where low blanket gas pressure can create a fluid heater system hazard.

A.11.2.4.11See A.11.2.4.10 .

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A.11.3.1.1Detecting only flow/no flow conditions is not adequate. A pressure switch at the pump discharge and a pump rotation switch are examples of proving devices that are not recommended to prove minimum flow as unexpectedblockages in the heater tubes will not be detected by these devices.


A.12.1This recommended practice addresses the fire protection needs of fluid heaters and related equipment. Fire protection needs external to this equipment are beyond the scope of this recommended practice.

Fire extinguishing systems and methods should be designed in accordance with fire protection engineering principles and applicable standards.

Hazards associated with combustible or high temperature fluid migration to other areas through open or incompletely sealed floors should be considered.Fixed fire protection for the equipment can consist of sprinklers, water spray, carbon dioxide, foam, dry chemical, water mist, or steam extinguishing systems. The extent of the protection depends on the construction, arrangement, and location of the fluid heater or related equipment as well as the materials being processed.

Hydrogen and other flammable gas fires normally are not extinguished until the supply of gas has been shut off because of the danger of re-ignition or explosion. Re-ignition can occur if a hot surface adjacent to the flame is not cooled with water or by other means. Personnel should be cautioned that hydrogen flames are invisible and do not radiate heat.A.12.1.1Where automatic fire protection systems are installed, alarming and actuation can be based on one or more of the following criteria:

(1) High values from differential flow detectors comparing fluid flowing into and out of the heater

(2) Low fluid level in the expansion tank (Note: This function can be used only if the expansion tank level is not automatically corrected with a pumped resupply of fluid from the storage tank.)

(3) High values from flue gas combustibles analyzer

(4) Increase in opacity of smoke exiting the heater


(6) Increase in carbon monoxide in flue gas

(7) Decrease in oxygen in flue gas

A.12.1.4Fire resistance duration, corrosion resistance, and weathering resistance should be considered when fireproofing is applied to heater structural members.

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A.12.2.1Sprinkler protection alone cannot ensure that a fire involving a fluid release will not cause catastrophic heater or building damage.

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Quick PrintAnnex B Example Maintenance ChecklistThis annex is not a part of the recommendations of this NFPA document but is included for informational purposes only.

B.1 General.The recommendations in this annex are for the maintenance of equipment. Different types of equipment need special attention. A preventive maintenance program, including adherence to the manufacturer’s recommendations, should be established and followed. The program should establish a minimum maintenance schedule that includes inspection and action on the recommendations provided in this annex. An adequate supply of spare parts should be maintained, and inoperable equipment should be cleaned, repaired, or replaced, as required.

B.2 Visual Operational Checklist.The following operational checks should be performed:

(1) Check burners for ignition and combustion characteristics. Verify flame shape and confirm that flames are not impinging on heat transfer surfaces.

(2) Check pilots or igniters, or both, for main burner ignition.

(3) Check air-to-fuel ratios.

(4) Check operating temperature.

(5) Check sight drains and gauges for cooling waterflow and water temperature.

(6) Check that burners and pilots have adequate combustion air.

(7) Check the operation of ventilating equipment.

(8) Inspect heater interior for signs of fluid leaks or tube overheating (e.g., ballooning or discoloration). Consider using infrared scanner to observe furnace interior and identify hot spots or other abnormalities.

(9) After each fuel shutoff, check the heater interior for glowing tubes (which could indicate fouling or plugging), flames due to combustible fluid leaks, or flames from burners due to fuel leaking past safety shutoff valves.

B.3 Regular Shift Checklist.The following operational checks should be performed at the start of every shift:

(1) Check the set point of control instrumentation.

(2) Check positions of hand valves, manual dampers, secondary air openings, and adjustable bypasses.

(3) Check blowers, fans, compressors, and pumps for unusual bearing noise and shaft vibration; if V-belt driven, belt tension and belt fatigue should be checked.

(4) Perform lubrication in accordance with manufacturer’s requirements.

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B.4 Periodic Checklist.The following maintenance checklist should be completed at intervals based onmanufacturers’ recommendations and the requirements of the process:

(1) Inspect flame-sensing devices for condition, location, and cleanliness.

(2) Inspect thermocouples and lead wire for shorts and loose connections. A regular replacement program should be established for all control and safety thermocouples. The effective life of thermocouples varies,depending on the environment and temperature, so those factors should be considered in setting up a replacement schedule.

(3) Check setting and operation of low and high temperature limit devices.

(4) Test visual and audible alarm systems for proper signals.

(5) Check igniters and verify proper gap.

(6) Check all pressure switches for proper pressure settings.

(7) Check control valves, dampers, and actuators for free, smooth action and adjustment.

(8) Test the interlock sequence of all safety equipment. If possible, the interlocks should manually be made to fail, thus verifying that the related equipment operates as specified by the manufacturer.

(9) Test the safety shutoff valves for operation and tightness of closure as specified by the manufacturer.

(10) Test the main fuel manual valves for operation and tightness of closure as specified by the manufacturer.

(11) Test the pressure switches for proper operation at set point.

(12) Visually inspect electrical switches, contacts, and controls for signs of arcing or contamination.

(13) Test instruments for proper response to thermocouple failure.

(14) Clean or replace the air blower filters.

(15) Clean the water, fuel, gas compressor, and pump strainers.(16) Clean the fire-check screens and valve seats and test for freedom of valve

movement.

(17) Inspect burners and pilots for proper operation, air-to-fuel ratio, plugging, and deterioration. Burner refractory parts should be examined to ensure good condition.

(18) Check all orifice plates, air–gas mixers, flow indicators, meters, gauges, and pressure indicators; if necessary, clean, repair, or replace them. Check calibrations as appropriate

(19) Check the ignition cables and transformers.(20) Check the operation of modulating controls.

(21) Check the integrity of and the interior of the equipment, ductwork, and ventilation systems for cleanliness and flow restrictions.

(22) Test pressure relief valves; repair or replace them as necessary.

(23) Inspect air, water, fuel, and impulse piping for leaks.

(24) Inspect radiant tubes and heat exchanger tubes for leakage; repair them as necessary.

(25) Lubricate the instrumentation, valve motors, valves, blowers, compressors, pumps, and other components.

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(26) Test and recalibrate instrumentation in accordance with manufacturers’ recommendations.

(27) Test flame safeguard units. A complete shutdown and restart should be made to check the components for proper operation.

(28) Check electric heating elements for contamination, distortion, cracked or broken refractory element supports, and proper position. Repair or replace elements if grounding or shorting could occur.

(29) Check electric heating element terminals for tightness.

(30) Perform required pressure vessel or pressure piping inspection and testing (e.g., in accordance with the requirements of the National Board of Boiler and Pressure Vessel Inspectors).

(31) If indications of overheating are observed, drain the fluid from the heater, perform an internal inspection to evaluate and eliminate the cause of the overheating, and assess the need for repair.

(32) Consider nondestructive testing of wall thicknesses by eddy-current, ultrasonic, or other means.

(33) Perform a fluid system leakage test by pressurizing the entire system to 11⁄2 times working pressures or maximum pump pressure, whichever is lower, but do not exceed the pressure setting of the pressure relief valves.

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Quick PrintAnnex C Steam Extinguishing SystemsThis annex is not a part of the recommendations of this NFPA document but is included for informational purposes only. This annex is extracted from NFPA 86, Standard for Ovens and Furnaces, Annex F.

C.1 General.Steam extinguishes fire by excluding air or reducing the oxygen content of theatmosphere in a manner similar to that of carbon dioxide or other inert gases.The use of steam preceded other modern smothering systems. Steam is not apractical extinguishing agent except where a large steam supply is continuouslyavailable. The possible burn hazard should be considered in any steamextinguishing installation. A visible cloud of condensed vapor, popularlydescribed as steam, is incapable of extinguishment. Although many fires havebeen extinguished by steam, its use often has been unsuccessful due to a lack of understanding of its limitations. Except for specialized applications, othertypes of smothering systems are preferred in modern practice. No completestandard covering steam smothering systems has yet been developed.

One pound of saturated steam at 212°F (100°C) and normal atmospheric pressure has a volume of 26.75 ft3 (0.76 m3). A larger percentage of steam isrequired to prevent combustion than in the case of other inert gases used forfire extinguishment. Fires in substances that form glowing coals are difficult to extinguish with steam, because of the lack of cooling effect. For some types of fire, such as fires involving ammonium nitrate and similar oxidizing materials, steam is completely ineffective.

Steam smothering systems should be permitted only where oven temperatures exceed 225°F (107°C) and where large supplies of steam are available at all times while the oven is in operation. A complete standard paralleling those for other extinguishing agents has not been developed for the use of steam as an extinguishing agent, and, until this is done, this form of protection is not as dependable as water, carbon dioxide, dry chemical, or foam extinguishing systems, nor are the results as certain. Release devices for steam smothering systems should be manual, and controls should be arranged to close down oven outlets to the extent practicable.

C.2 Life Hazard.C.2.1Equipment should be arranged to prevent the operating of steam valves when doors of box-type ovens or access doors or panels of conveyor ovens are open.

C.2.2A separate outside steam manual shutoff valve should be provided for closing off the steam supply during oven cleaning. The valve should be locked closedwhenever employees are in the oven.

C.2.3

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The main valve should be designed to open slowly, because the release should first open a small bypass to allow time for employees in the vicinity to escape in an emergency and also to protect the piping from severe water hammer. A steam trap should be connected to the steam supply near the main valve to keep the line free of condensate.

C.3 Steam Outlets.If steam is used, steam outlets should be sufficiently large to supply 8 lb/min (3.6 kg/min) of steam for each 100 ft3 (2.8 m3) of oven volume. They preferably should be located near the bottom of the oven, but if the oven is not over 20 ft (6.1 m) high, they might be located near the top, pointing downward. Steam jetsshould be directed at dip tanks (in a manner to avoid disturbing the liquidsurface) or other areas of special hazard.

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Quick Print


Annex D Informational ReferencesD.1 Referenced Publications.The documents or portions thereof listed in this annex are referenced within the informational sections of this recommended practice and are not part of the recommendations of this document unless also listed in Chapter 2 for other reasons.

D.1.1 NFPA Publications.National Fire Protection Association, 1 Batterymarch Park, Quincy, MA 02169-7471.

NFPA 30, Flammable and Combustible Liquids Code, 2008 edition.

NFPA 31, Standard for the Installation of Oil-Burning Equipment, 2006 edition.

NFPA 33, Standard for Spray Application Using Flammable or CombustibleMaterials, 2011 edition.

NFPA 34, Standard for Dipping, Coating, and Printing Processes UsingFlammable or Combustible Liquids, 2011 edition.

NFPA 54, National Fuel Gas Code, 2009 edition.

NFPA 68, Standard on Explosion Protection by Deflagration Venting, 2007 edition.NFPA 69, Standard on Explosion Prevention Systems, 2008 edition.


NFPA 85, Boiler and Combustion Systems Hazards Code, 2007 edition.


NFPA 91, Standard for Exhaust Systems for Air Conveying of Vapors, Gases,Mists, and Noncombustible Particulate Solids, 2010 edition.

NFPA 497, Recommended Practice for the Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for ElectricalInstallations in Chemical Process Areas, 2008 edition.

NFPA 499, Recommended Practice for the Classification of Combustible Dustsand of Hazardous (Classified) Locations for Electrical Installations in ChemicalProcess Areas, 2008 edition.

D.1.2 Other Publications.

D.1.2.1 ANSI Publications.American National Standards Institute, Inc., 25 West 43rd Street, 4th Floor, New York, NY 10036.

ANSI A14.3, Safety Requirements for Fixed Ladders, 2008.

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ANSI/ISA 84.00.01, Application of Safety Instrumented Systems for the ProcessIndustries, 2004.

ANSI Z21.18/CSA 6.3, Standard for Gas Appliance Pressure Regulators, 2007.

ANSI Z21.21/CSA 6.5, Automatic Valves for Gas Appliances, 2005.

ANSI Z117.1, Safety Requirements for Confined Spaces, 2003.


D.1.2.2 ASME Publications.American Society of Mechanical Engineers, Three Park Avenue, New York, NY 10016-5990.ANSI/ASME B31.3, Process Piping , 2008.

D.1.2.3 EN Publications.European Committee for Standardization, 36, rue de Stassart, B-1050, Brussels, Belgium.

EN 161, Automatic Shut-Off Valves for Gas Burners and Gas Appliances, 2007.

EN 1643, Valve Proving Systems for Automatic Shut-Off Valves for GasBurners and Gas Appliances, 2000.

D.1.2.4 FM Publications.FM Global, 1301 Atwood Avenue, P.O. Box 7500, Johnston, RI 02919.

FM 7400, Approval Standard for Liquid and Gas Safety Shutoff Valves, 1998.


D.1.2.5 IEC Publications.International Electrical Commission, 3 rue de Varembé, P.O. Box 131, CH -1211, Geneva 20, Switzerland.IEC 61511, Functional Safety: Safety Instruments Systems for the Process Industry Sector , 2004.

D.1.2.6 NBBPVI Publications.National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Avenue, Columbus, OH 43229.

National Board Inspection Code, 2007.

D.1.2.7 NIOSH Publications.National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 3033.

NIOSH Pocket Guide to Chemical Hazards, 2005.D.1.2.8 UL Publications.Underwriters Laboratories Inc., 333 Pfingsten Road, Northbrook, IL 60062-2096.

UL 353, Standard for Limit Controls, 1994. Revised 2009.

UL 429, Standard for Electrically Operated Valves, 1999.

D.1.2.9 U.S. Government Publications.U.S. Government Printing Office, Washington, DC 20402.

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Title 29, Code of Federal Regulations, Parts 1910.24 through 1910.29.

D.2 Informational References.The following documents or portions thereof are listed here as informationalresources only. They are not a part of the recommendations of this document.

D.2.1 ABMA Publications.American Boiler Manufacturers Association, 8221 Old Courthouse Road, Suite 207, Vienna, VA 22182.

ABMA 203, A Guide to Clean and Efficient Operation of Coal-Stoker-FiredBoilers, 2002.

ABMA 307, Combustion Control Guidelines for Single Burner Firetube andWatertube Industrial/Commercial/Institutional Boilers, 1999.

D.2.2 ANSI Publications.American National Standards Institute, Inc., 25 West 43rd Street, 4th Floor, New York, NY 10036.

ISA S77.41.01, Fossil Fuel Power Plant Boiler Combustion Controls, 2005.ANSI/ISA S77.42.01, Fossil Fuel Plant Feedwater Control System — DrumType, 2006.

ISA S77.44.01, Fossil Fuel Plant — Steam Temperature Controls, 2007.

D.2.3 API Publications.American Petroleum Institute, 1220 L Street, NW, Washington, DC 20005.

API STD 620, Design and Construction of Large, Welded, Low-PressureStorage Tanks, 2009.

API STD 650, Welded Tanks for Oil Storage, 2009.

API STD 653, Tank Inspection, Repair, Alteration and Reconstruction, 2009.API RP 500, Recommended Practice for Classification of Locations forElectrical Installation at Petroleum Facilities Classified as Class I, Division 1 and Division 2, 1998 (reaffirmed 2002).

API RP 2003, Protection Against Ignitions Arising Out of Static, Lightning, and Stray Currents, 2008.

D.2.4 ASME Publications.American Society of Mechanical Engineers, Three Park Avenue, New York, NY10016-5990.

Boiler and Pressure Vessel Code, 2007.

D.2.5 ASTM Publications.ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959.

ASTM D 396, Standard Specification for Fuel Oils, 2009.

D.2.6 Other Publications.The following documents provide additional information about heat recovery steam generators (HSRGs).

Johnson, A. A., J. A. von Fraunhofer, and E. W. Jannett, “Combustion of Finned Steel Tubing During Stress Relief Heat Treatment,” Journal of Heat Treating, 4(3), June 1986, pp. 265–271.McDonald, C. F., “The Potential Danger of Fire in Gas Turbine Heat Exchangers,” ASME 69-GT-38.

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Theoclitus, G., “Heat Exchanger Fires and the Ignition of Solid Metals,” Journal of Engineering for Gas Turbines and Power, 107, July 1985, pp. 607–612.

D.3 References for Extracts in Informational Sections.NFPA 86, Standard for Ovens and Furnaces, 2011 edition.

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1/18/13 TerraView™

submittals.nfpa.org/TerraViewWeb/ViewerPage.jsp 1/102

Public Input No. 25-NFPA 87-2012 [ Global Input ]

Proposal: Identify all defined terms in the NFPA 86 Standard with bold/italicizedfont.

Example from CSA B149.3 (I could not paste excerpt here)

Statement of Problem and Substantiation for Public Input

CSA B149.3 uses this convention and it is very helpful to the user to know when a specially defined term is being used, thereby directing the reader’s attention to the Definitions.

Submitter Information Verification

Submitter FullName:

Ted Jablkowski

Organization: Fives North American Combustio

Affilliation:Similar public input developed in conjunction with NFPA 86 Intro ChaptersTask Group

Submittal Date: Thu Jun 21 17:58:12 EDT 2012

Committee Statement

Resolution: The committee did not accept the recommendation because consistentimplementation would be difficult.

Copyright Assignment

I, Ted Jablkow ski, hereby irrevocably grant and assign to the National Fire Protection Association (NFPA) all and

full rights in copyright in this Public Input (including both the Proposed Change and the Statement of Problem and

Substantiation). I understand and intend that I acquire no rights, including rights as a joint author, in any

publication of the NFPA in w hich this Public Input in this or another similar or derivative form is used. I hereby

w arrant that I am the author of this Public Input and that I have full pow er and authority to enter into this

copyright assignment.

By checking this box I aff irm that I am Ted Jablkow ski, and I agree to be legally bound by the above

Copyright Assignment and the terms and conditions contained therein. I understand and intend that, by checking

this box, I am creating an electronic signature that w ill, upon my submission of this form, have the same legal

force and effect as a handw ritten signature




Replace all piping symbols used throughout the Standard with ISA symbols.

Examples are:

Figure A.7.5.15(a)

Figure A.8.7.1.2

Figure A.8.7.2


NFPA documents should be using symbols defined in other national standards.


Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: The committee would like to see revised diagrams to ensure that there are nounintended consequences of the global change.















Change NFPA 87 from a Recommended Practice to a Standard. Reviserequirements in the body text to mandatory langauge.


NFPA 87 is becoming recognized as a design Standard for Fluid Heaters and is being specified for new systems. Absent any other requirements for Fluid Heaters goverened by NFPA 87, the Recommended Practice is viewed and used as a Standard. Unless there is some significant public comments pointing to the inadeaqucy of this Recommended Practice, it seems its introduction as a Recommended Practice has sereve its purpose as the precursor of its evolution to a Standard.


Submitter Full Name:Ted Jablkowski


Submittal Date: Fri Jun 22 05:41:34 EDT 2012

Committee Statement

Resolution: It is the intent of the committee to convert the recommended practice to a standardin the next revision cycle. The committee is introducing three new chapters to thisrevision and wants to ensure that users have adequate experience with the newmaterial before converting to requirements.















Where appropriate for Fluid Heaters, the requirements in Chapters 4, 5, 6, 7 and 8,should closely duplicate the related requirements in the most current NFPA 86Standard for Ovens and Furnaces.


The so called Intro Chapters or common requirements for combustion systems seem to be universal between the applications goverened by both NFPA 86 and 87.


Submitter Full Name:Ted Jablkowski



Committee Statement

Resolution: The committee satisfied the submitter's intent through action on other public inputthat are too numerous to list here.














Public Input No. 16-NFPA 87-2012 [ Section No. 2.3.4 ]

2.3.4 UL Publications.

Underwriters Laboratories Inc., 333 Pfingsten Road, Northbrook, IL 60062-2096.

UL 795, Standard for Commercial-Industrial Gas Heating Equipment, 2006 2011 .


Update referenced standard to most recent edition as indicated.


Submitter Full Name:John Bender

Organization: Underwriters Laboratories Inc.

Submittal Date: Wed Apr 18 13:30:32 EDT 2012

Committee Statement

Resolution: FR-1-NFPA 87-2012

Statement: Update referenced standard to most recent edition as indicated.


I, John Bender, hereby irrevocably grant and assign to the National Fire Protection Association (NFPA) all and






By checking this box I aff irm that I am John Bender, and I agree to be legally bound by the above Copyright

Assignment and the terms and conditions contained therein. I understand and intend that, by checking this box, I

am creating an electronic signature that w ill, upon my submission of this form, have the same legal force and

effect as a handw ritten signature



Public Input No. 20-NFPA 87-2012 [ New Section after 3.3.3 ]

TITLE OF NEW CONTENT

3.3.4* Burner Management System. The field devices, logic system, and final controlelements dedicated to combustion safety and operator assistance in the starting andstopping of fuel preparation and burning equipment and for preventing misoperation of anddamage to fuel preparation and burning equipment.


The term Burner Management System is used to describe the Logic Systems described in section 8.3. The definition proposed is directly from NFPA 85-2011. The annex material proposed is new for NFPA 87.


Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: The term Burner Management System is used to describe the Logic Systemsdescribed in section 8.3. The definition proposed is directly from NFPA 85-2011.The annex material proposed is new for NFPA 87.















3.3.5 Combustion Safeguard.

A safety control directly responsive to flame properties that senses the presence orabsence of flame and de-energizes the fuel safety shutoff valve in the event of flamefailure using flame sensors .


revise for current definition in NFPA 86-2011.


Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: The committee did not modify the definition because the combustion safeguard isnot limited to just the flame sensing system.














Public Input No. 53-NFPA 87-2012 [ New Section after 3.3.7.2 ]


3.3.8 Equipment Isolation Valve. A manual shutoff valve for shutoff of the fuel to eachpiece of equipment.

3.3.9 Emergency Shutoff Valve. A manual shutoff valve to allow the fuel to be turned offin an emergency.


Same as NFPA 86-2011.


Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: Same as NFPA 86-2011. The terms are defined to distinguish between two valvesthat have different purposes and requirements.
















Add Definition after 3.3.8 and renumber.

3.3.9 Flame Response Time (FRT). The period of time that starts with the loss offlame and ends with the de-energizing of the terminals of the safety shut-off valves


Substantiation for 8.5.2.1, 8.9.1 and Flame Response Time definition. The original definition of the combustion safeguard included a flame relay and all of the associated logic and the new definition is just a flame sensor. The flame sensor cannot perform a safe start check as that is a logic function.I believe it was the intent of the code to mandate that the maximum time between the loss of flame and the de-energizing of the SSOVs to be 4 seconds. If that assumption is true then the flame scanner cannot consume all of the allotted time. Time must be left for the logic solver and interfacing logic to de-energize the safety shut-off valves.If the intent is to permit the flame sensor to take up to 4 seconds then we must decide what is a reasonable time for the logic solver to actuate the valves and for the valves to close.


Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: The term is not used in the body of the standard.















3.3.8 Explosive Range 8 Flammable Limit .

The range of concentration of a flammable gas in air within which a flame can bepropagated, with the lowest flammable concentration known as the lower explosivelower flammable limit (LEL LFL ), and the highest flammable concentration knownas the upper explosive upper flammable limit (UEL UFL ).


Revise same as NFPA 86-2011.


Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: Revised to be consistent with NFPA 86-2011.
















Hardwired. The method of interconnecting signals or interlocks to a logic system orbetween logic systems using a dedicated interconnection for each individual signal. Whenthe term hardwired is applied to the logic system itself, it refers to the method of usingindividual devices and interconnecting wiring to program and perform the logic functionswithout the use of software-based logic solvers.


“Hardwired” is used in NFPA 87 and not defined. Definition is from NFPA 85-2011.


Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: “Hardwired” is used in NFPA 87 and not defined. Definition is from NFPA 85-2011.New definition that is not replacing any current definition, renumber subsequentsections. See FR-63-NFPA 87-2012 for the annex material for this FR.















3.3.15 Lower Explosive 15 Lower Flammable Limit (LEL LFL ).

See 3.3.8, Explosive Range Flammable Limits .


Revise per NFPA 86-2011. Replace LEL with LFL throughout document.


Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: Revised to be consistent with NFPA 86-2011. Replace LEL with LFL throughoutdocument.














Public Input No. 1-NFPA 87-2012 [ Section No. 3.3.30.1 ]

3.3.30.1 Catch Tank.

A tank used to capture liquid from drains, relief valves, vents, and overflows.


Text deleted because term is no longer used in the document.


Submitter Full Name:Richard Martin

Organization: Martin Thermal Engineering, Inc.

Affilliation: Secretary of NFPA 87 Task Group on Class F and Class G Fluid Heaters

Submittal Date: Fri Mar 02 12:11:44 EST 2012

Committee Statement


Statement: Text deleted because term is no longer used in the document.


I, Richard Martin, hereby irrevocably grant and assign to the National Fire Protection Association (NFPA) all and






By checking this box I aff irm that I am Richard Martin, and I agree to be legally bound by the above Copyright








4.1.3.2 Where seal leakage or diaphragm failure in a device can result in flammable gasor flammable liquid flow through a conduit or cable to an electrical ignition source, aconduit seal or a cable type that is sealed shall be installed.




Submitter FullName:

Ted Jablkowski




Committee Statement

















5.1.4.1

Fluid heaters should be located with spaceSpace shall be provided above and on all sides for

inspection and maintenance purposes.the following: (1) Inspection, maintenance, and operation purposes

(2) Operation of explosion venting

(3) Operation and unobstructed discharge of sprinklers


same as NFPA 86-2011.


Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: The Committee believes that space required for explosion venting and sprinklers iscovered by NFPA 68 and NFPA 13, respectively.















5.4.3.3*

Where ducts pass through fire resistance–rated or noncombustible walls, floors, orpartitions, the space around the duct should be sealed with a noncombustiblematerial that will to maintain the fire-resistance rating of the barrier.




Submitter FullName:

Ted Jablkowski




Committee Statement

















5.4.3.5*

No portions of the building should be used as an integral part of the duct leading toa safe point of discharge .


1st to revise to be same as NFPA 86-2011 and 2nd to change from approved to safe.At a recent NFPA 85 TC meeting, I learned that NFPA does not have a restriction on the use of “safe” in the context of “safe location” as being unenforceable language and that NFPA 85 uses “safe location” in mandatory text. See 6.6.3.1.2.2 in NFPA 85-2011.


Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: The committee did not accept the recommendation because the revised text wouldlimit application to exhaust ducts. There could be a hazard related to a ducted airintake that is addressed by the existing text.















5.4.3.5*

No portions of the building should be used as an integral part of the duct leading tothe safe point of discharge .


Sames as NFPA 86-2011.


Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: The committee did not accept the recommendation because the revised text wouldlimit application to exhaust ducts. There could be a hazard related to a ducted airintake that is addressed by the existing text.















5.4.3.11

Exhaust ducts should not discharge near openings or other air intakes whereeffluents can enter a building be entrained and directed to locations creating ahazard .




Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: Revise to be consistent with NFPA 86-2011.















5.5.1.3.1

In applications where fluid leakage creates a hazard and where a welded connection is notpossible, a flanged connection should be used.


This input and the related text (5.5.1.3 and 5.5.1.3.2) clarifies the committee's intent that welded connections should be used as often as is practical.






Committee Statement


Statement: This revision and the new subtext (5.5.1.3.1 and 5.5.1.3.2) clarifies the Committee'sintent that welded connections should be used as often as is practical.















5.5.1.3.2

In applications where fluid leakage creates a hazard and were a welded or a flangedconnection is not possible, a threaded connection utilizing a pipe size less than 1” isacceptable.


This input and the related text (5.5.1.3 and 5.5.1.3.1) clarifies the committee's intent that welded connections should be used as often as is practical.






Committee Statement

















5.5.1.3*

Flanged and threaded connections in the flow circuit should be minimized Inapplications where fluid leakage creates a hazard, all pipe connection should bewelded .


This input and the new subtext (5.5.1.3.1 and 5.5.1.3.2) clarifies the committee's intent that welded connections should be used as often as is practical.






Committee Statement

















6.2.4.1*

A remotely located

An emergency shutoff valve

should

shall be provided

to allow the fuel to be turned off in an emergency and should be located

that meets the following requirements:

(1) It shall be remotely located away from the furnace so that fire orexplosion at

the fluid heater

a furnace does not prevent access to the valve.

(2) It shall be readily accessible.

(3) It shall have permanently affixed visual indication of the valve position.

(4) A removable handle shall be permitted provided all the followingrequirements are satisfied:

(a) The valve position shall be clearly indicated whether the handle isattached or detached.

(b) The valve handle shall be tethered to the gas main no more than3 ft (1 m) from the valve in a manner that does not cause personnelsafety issues and that allows trouble-free reattachment of the handleand operation of the valve without untethering the handle.

(5) It shall be able to be operated from full open to full close and returnwithout the use of tools.


Same text as in NFPA 86.


Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: Revised for consistency with NFPA 86.






6.2.4.4 An equipment isolation valve shall be provided.


same as NFPA 86-2011.


Submitter FullName:

Ted Jablkowski




Committee Statement















6.2.5.1

Individual manual shutoff valves for equipment isolation should be provided for shutoff of thefuel to



Equipment Isolation Valves. Equipment isolation valves shall meet thefollowing requirements:

(1) They shall be provided for each piece of equipment.

(

A) Manual shutoff valves should

2) They shall have permanently affixed visual indication of the valve position.

(

B) Quarter-turn valves should

3) They shall be quarter-turn valves with stops.

(4) Wrenches or handles shall remain affixed to valves and shall be orientedwith respect to the valve port to indicate the following:

(a) An open valve when the handle is parallel to the pipe

(b) A closed valve when the handle is perpendicular to the pipe

(5) They shall be readily accessible.

(6) Valves with removable wrenches shall not allow the wrench handle to beinstalled perpendicular to the fuel gas line when the valve is open.

(

C) Wrenches or handles should remain affixed to valves

7) They shall be able to be operated from full open to full close and returnwithout the use of tools .


Same as in NFPA 86.


Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: Revised to be consistent with NFPA 86.





6.2.7.4*

Fuel gas regulators, ratio regulators, and zero governors are not required to bevented to an approved a safe location in the following situations:

(1) Where backloaded from combustion air lines, air–gas mixture lines, orcombustion chambers, provided that gas leakage through the backloadconnection does not create a hazard

(2) Where a listed regulator–vent limiter combination is used

(3) Where a regulator system is listed for use without vent piping


At a recent NFPA 85 TC meeting, I learned that NFPA does not have a restriction on the use of “safe” in the context of “safe location” as being unenforceable language and that NFPA 85 uses “safe location” in mandatory text. See 6.6.3.1.2.2 in NFPA 85-2011.


Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: The existing language is appropriate and enforceable. The term safe is subjectiveand unenforceable.














Public Input No. 31-NFPA 87-2012 [ Sections 6.2.7.7, 6.2.7.8 ]

Sections 6.2.7.7, 6.2.7.8

6.2.7.7

Vent lines from multiple regulators and switches of a single fluid heater, wheremanifolded together, should be piped in such a manner that diaphragm rupture ofone vent line does not backload the others.

6.2.7.

8 The size of the vent manifold specified in

7.1 Vents from systems operating at different pressure levels shall not bemanifolded together.

6.2.7.7

should be not less than the

.2 Vents from systems served from different pressure reducing stationsshall not be manifolded together.

6.2.7.7.3 Vents from systems using different fuel sources shall not bemanifolded together.

6.2.7.8

The cross-sectional area of the manifold line shall not be less than thegreater of the following:

(1) The cross-sectional area of the largest vent

lineplus 50 percent of the sum of the cross-sectional areas of the additionalvent

line area.lines

(2) The sum of the cross-sectional areas of the two largest vent lines


NFPA 87 doesn’t specifically prohibit manifolding vent lines from different pressure sources. It is good engineering practice not to do this and it is not allowed in NFPA 85. This is something that should be addressed in more specifically in NFPA 87. The proposed subparagraphs are extracted from NFPA 85 (2011), Section 4.9.3.


Submitter FullName:

Ted Jablkowski






Committee Statement


Statement: NFPA 87 doesn’t specifically prohibit manifolding vent lines from different pressuresources. It is good engineering practice not to do this and it is not allowed in NFPA85. This is something that should be addressed in more specifically in NFPA 87.The proposed subparagraphs are extracted from NFPA 85 (2011), Section 4.9.3.
















6.2.7.9 * A vent between safety shutoff valves, where installed:

(1) Shall not be combined with other vents

(2)* Shall terminate to an approved location

A.6.2.7.9 NFPA 87 does not address vents between safety shutoff valves, but they aresometimes installed.




Submitter FullName:

Ted Jablkowski




Committee Statement














http://codesonline.nfpa.org/a/c.ref/2011_ID020086011715/sec





6.2.7.8

The size of the vent manifold specified in 6.2.7.7 should be not less than the areaof the largest vent line plus 50 percent of the of each additional vent line area.


Same as public comment to NFPA 86-2011.


Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: NFPA 87 doesn’t specifically prohibit manifolding vent lines from different pressuresources. It is good engineering practice not to do this and it is not allowed in NFPA85. This is something that should be addressed in more specifically in NFPA 87.The proposed subparagraphs are extracted from NFPA 85 (2011), Section 4.9.3.















6.3.4.2

The liquid fuel shutoff should be by either of the following:

A remotely located liquid fuel shutoff valve

Means for removing power to the positive displacement liquid fuel pump

(1) Emergency shutoff valve that meets the following requirements:(a) It shall be remotely located away from the furnace so that fire or explosionat a furnace does not prevent access to this valve.

(b) It shall be readily accessible.

(c) It shall have permanently affixed visual indication of the valve position.

(d) A removable handle shall be permitted provided all the followingrequirements are satisfied:

i. The valve position shall be clearly indicated whether the handle is attachedor detached.

ii. The valve handle shall be tethered to the gas main no more than 3 ft (1 m)from the valve in a manner that does not cause personnel safety issues andthat allows trouble-free reattachment of the handle and operation of the valvewithout untethering the handle.

(e) It shall be able to be operated from full open to full close and return withoutthe use of tools.


same as in NFPA 86-2011.


Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: Revised for consistency with NFPA 86-2011.
















6.3.4.7 An equipment isolation valve shall be provided.




Submitter FullName:

Ted Jablkowski




Committee Statement

















6.3.5.3

Liquid fuel piping should be sized to provide flow rates and pressure to maintain astable flame over the burner operating range.




Submitter FullName:

Ted Jablkowski




Committee Statement

















A confirmed source of combustible gas shall be provided to the inlet of theequipment isolation valve(s) (see 6.2.4.1) each time a combustible gas supply isplaced into service or restored to service.


New text added for consistency with NFPA 86 (TIA 11-3) and modifications to NPFA 54 regarding purging of natural gas lines during commissioning.



Organization: Martin Thermal Engineering

Affilliation: Secretary of NFPA 87 Task Group on Introductory Chapters

Submittal Date: Sun Apr 15 23:18:56 EDT 2012

Committee Statement


Statement: New Text added for consistency with NFPA 86 (TIA 11-3) and modifications toNFPA 54 regarding purging of natural gas lines during commissioning. See FR-64-NFPA 87-2012 for annex material.















A.7.1.7 The evacuation/purging, charging, and confirmation of the fuel orcombustible gas supply in the piping upstream of the equipment isolation valveis governed by other codes, standards, and recommended practices. Oneexample is NFPA 54, National Fuel Gas Code, 2009 edition, Section 8.3 (ref: TIA09-3 effective 08/25/10), which requires charging to be stopped upon detectionof combustible gas at the point of discharge. Careful consideration should begiven to the potential hazards that may be created in the surrounding area forany fuel or combustible gas discharge.


Annex material added to new text at 7.1.7 for consistency with NFPA 86 (TIA 11-3).




Affilliation: Secretary of NFPA 87 Introductory Chapters Task Group


Committee Statement



















7.2.12* A confirmed source of combustible gas shall be provided to the inlet to theequipment isolation valve(s) (see 6.2.5.1) each time a combustible gas supply is placedinto service or restored to service.

A.7.2.12 The evacuation/purging, charging and confirmation of the fuel or combustible gassupply in the piping upstream of the equipment isolation valve is goverend by other codes,standards and recommended practices. Examples are NFPA 54, National Fuel Gas Code,2012 edition Chapter 8, which requires charging to be stopped upon detection ofcombustible gas at the point of discharge, and NFPA 56PS - Standard for Fire andExplosion Prevention During Cleaning and Purging of Flammable Gas Piping Systems.Careful consideration should be given to the potential hazards that may be created in thesurrounding area for any fuel or combustible gas discharge.

In NFPA 54, the term Appliance Shutoff Valve is analogous to the term Equipment IsolationValve in NFPA 86 and 87.


This proposal is the result of requests by NFPA to create such requirements following recent accidents.


Submitter FullName:

Ted Jablkowski




Committee Statement

















7.5.15*

Valve seat leakage testing of fuel gas safety shutoff valves and valve provingsystems should be performed in accordance with the manufacturer's instructions,and testing .

7.5.15.1 Testing frequency should be at least annually.




Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: Same as NFPA 86-2011.















7.5.22

Whenever combustible gas piping is placed into service or removed from service, anyrelease of combustible gas shall be vented to an approved location.


New text added to be consistent with NFPA 86 (TIA 11-3) regarding purging natural gas lines to an approved location.






Committee Statement


Statement: Related change to charging and purging of combustible gas systems as requestedof NFPA due to recent accidents. See See FR-65-NFPA 87-2012 for annex to thisnew section.
















7.5.22 Safety Shutoff Valve Replacement.

7.5.22.1 Safety shutoff valves shall be replaced before they exceed their maximumallowable number of lifetime open–closed cycles.

7.5.22.2 When the maximum allowable number of lifetime open–closed cycles for Safetyshutoff valves are not available from the Safety shutoff valves manufacturer, the user mustreplace the Safety shutoff valves when their leak tightness tests indicate that the leakagehas increased to the level that is 100% greater than the previously required leak tightnesstest or 44 bubbles per minute or when the leakage is of a level that would result in acondition in the furnace of greater than 25% LFL for all possible circumstances.

7.5.22.3 * The number of safety shutoff valve cycles shall be determined in one of thefollowing ways:

(1) By counting the number of actual safety shutoff valve open-closed cycles

(2) By estimating the time to reach 90 percent of lifetime total cycles based on normalcycling rates

A.7.5.22.3 Where a means is not provided to count the actual number of safety shutoff valvecycles, it becomes a maintenance responsibility to maintain an estimate of safety shutoffvalve cycles so that the safety shutoff valve is replaced before it exceeds 90 percent of thelife cycles established by the safety shutoff valve manufacturer.


1. Include same requirement as in NFPA 86-2011.

2. It is very difficult to be compliant with this Standard when the manufacturers of Listed SSOV will not provide life cycle ratings. This proposal attempts to provide an alternate determination for SSOV replacement when life cycle ratings are not available.


Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: The committee believes that the recommended text does not apply to fluid heaterapplications.













7.5.22 Whenever combustible gas piping is placed into service or removed from service,any release of combustible gas shall be vented to a safe location.

A.7.5.22 See 6.2.6.3


Related change to charging and purging of combustible gas systems as requested of NFPA due to recent accidents. See TIA86-11-3.


Submitter FullName:

Ted Jablkowski




Committee Statement

















8.2.2

All safety devices should meet one of the following criteria:

(1) Be listed for the service intended intended

(a) Combustion Safeguards, Excess Temperature Interlocks and Safety ShutoffValves be listed for combustion safety service

(1) Be approved, where listed devices are not available

(2) Be programmable controllers applied in accordance with Section 8.4


As per a pending public comment to NFPA86-2011. Clarifies intent of intended service.


Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: The committee believes the existing item (1) addresses the intent of the submitter.
















8.2.10 Shutdown of the heating system by any safety feature or safety device shallrequire manual intervention of an operator for re-establishment of normal operation of thesystem.8.2.11 * If the inlet pressure to a fuel pressure regulator exceeds the pressure rating ofany downstream component, overpressure protection shall be provided.

A.8.2.11 Overpressure protection can be provided by the use of components with adequaterating, relief valves with adequate capacity, slam-shut regulators, high pressure switch incombination with adequately rated upstream shutoff valves, or other devices, such asthose referenced in NFPA 54, National Fuel Gas Code, and NFPA 31, Standard for theInstallation of Oil-Burning Equipment. (Also see A.6.2.6.3 .)




Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: The new paragraph is added to be consistent with NFPA 86.













http://codesonline.nfpa.org/a/c.ref/NFC54/book

http://codesonline.nfpa.org/a/c.ref/NFC31/book






8.2.10 Where transmitters are used in place of switches for safety functions, the followingshall apply:

(1) The transmitter shall possess a MTBF rating of 250,000 hours, or possess a safetyintegrity level (SIL) rating of 2.

(2) Transmitter failure shall be detected and initiate a safety shutdown.

(3) The transmitter shall be dedicated to safety service unless listed for simultaneousprocess and safety service.


Taken from public comment to NFPA 86-2014. Relocated the transmitter requirement from PLC subsection and makes it generally applicable to all safety controls systems (including hardwired). Also see Public Comment to delete from 8.4.6.


Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: Relocated the transmitter requirement from PLC subsection and makes it generallyapplicable to all safety controls systems (including hardwired). Also see PublicComment to delete from 8.4.6.















8.2.9*

A manual Manual emergency switch(es) should be provided to initiate a safetyshutdown.


The 2011 Edition’s implies there is to be a single manual emergency switch. Depending upon the type of furnace there maybe multiple manual emergency switches to address the multiple “safety” hazards of the furnace. All of the furnace’s safety hazards should be evaluated and a manual emergency “system” should be designed/incorporated into the furnace design.


Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: The 2011 Edition implies there is to be a single manual emergency switch.Depending upon the type of fluid heater there maybe multiple manual emergencyswitches to address the multiple “safety” hazards of the fluid heater. All of the fluidheater's safety hazards should be evaluated and a manual emergency “system”should be designed/incorporated into the fluid heater design. The intent of thecommittee is to ensure that at least one emergency shutdown switch is hardwiredand operational without use of a PLC or other logic.














Public Input No. 19-NFPA 87-2012 [ Section No. 8.3 ]

8.3* Logic Systems Burner Management System Logic .

8.3.1 General.

8.3.1.1

Purge, ignition trials, and other burner safety sequencing should be performed usingeither devices listed for such service or programmable controllers used inaccordance with 8.4.

8.3.1.2

The activation of any safety interlock recommended in Chapter 8 should result in asafety shutdown.

8.3.2 Hardwired Logic Systems.

8.3.2.1

Safety interlocks should be in accordance with one or more of the following:

(1) Hardwired without relays in series ahead of the controlled device

(2) Connected to an input of a programmable controller logic system complyingwith Section 8.4

(3) Connected to a relay that represents a single safety interlock configured toinitiate safety shutdown in the event of power loss

(4) Connected to a listed safety relay that represents one or more safetyinterlocks and initiates safety shutdown upon power loss

8.3.2.2*

Electrical power for safety control circuits should be dc or single-phase ac, 250 voltmaximum, one-side grounded, with all breaking contacts in the ungrounded, fuse-protected, or circuit breaker–protected line.




Submitter FullName:

Ted Jablkowski




Committee Statement




Statement: General revisions to sections 8.3 and 8.4 to clarify Committee intent regarding logicsystems and the application of PLC’s. SIL 3 was chosen because SIL 3 equipmentinherently provides the separation and locking of the safety functions from otherfunctions. The list of struck items from existing 8.4.2.5 are standard functions of SIL3 PLCs. Therefore, listing them is redundant. The intent of the committee is toensure that at least one emergency shutdown switch is hardwired and operationalwithout use of a PLC or other logic.













8.3.1.1

Purge , ignition trials, and other burner safety sequencing and ignition trials shouldbe performed using either either listed devices listed for such service orprogrammable controllers used in accordance with 8.4.


The deletion allows the common practice of implementing “burner safety sequences” as hardwired systems according to Section 8.3.2. Example safety functions include 8.5.2.4 (spark interruption), 8.14 (low fire start), 8.6.3 (combustion air blower proof), and 8.7.2.2 (prove closed). Hardwired systems are in conflict with 8.3.1.1 unless the whole control system is listed as a device for these safety functions. Alternately, these functions must be handled in a listed programmable/modulating combustion safeguard controller.


Submitter FullName:

Ted Jablkowski






Committee Statement














Public Input No. 64-NFPA 87-2012 [ Sections 8.4.1, 8.4.2 ]

Sections 8.4.1, 8.4.2

8.4.1

PLC-based

Programmable logic controller (PLC)–based systems listed for combustionsafety service

should

shall be used in accordance with the listing requirements and themanufacturer's instructions.

8.4.

1.1

PLCs, except those listed for combustion safety service, should be used inaccordance with 8.4.2 through 8.4.4 .

8.4.2 General.



2 PLCs and associated I/O used to perform safety functions shall becertified to IEC 61508 for use in safety applications with a safety integritylevel of 2 or greater. The safety functions shall be implemented accordingto the device’s safety manual requirements to achieve a safety integritylevel of 2 or greater.

8.4.3 General Purpose PLCs shall be permitted to time purge.

8.4.

2

4 General .

1

(A) Before the PLC is placed in operation, documentation

should

shall be provided that confirms that all related safety devices andsafety logic are functional.

8.4.2.2

(B) All changes to hardware or software

should

shall be documented and maintained in a file that is separatefrom the

fluid heater PLC.

8.4.2.3

System operation should

furnace programmable controller.

(C) System operation shall be tested and verified for compliancewith the design criteria when the PLC is replaced, repaired, orupdated.

8.4.2.4

(D) The control system

should

shall have at least one manual emergency switch that initiates asafety shutdown.

8.4.

2

5 Software .

5



The PLC should detect the following conditions:

(1) Failure to execute any program or task containing safety logic

(2) Failure to communicate with any safety input or output

(3) Changes in software set points of safety functions

(4) Failure of outputs related to safety functions

(5) Failure of timing related to safety functions

8.4.2.6

A safety shutdown should occur within 3 seconds of detecting any condition listedin 8.4.2.5 .

8.4.2.7

A dedicated PLC output should initiate a safety shutdown for faults detected by thePLC.

8.4.2.8

The following devices and logic should be hardwired external to the PLC as follows:

(1) Manual emergency switch

(2) Combustion safeguards

(3) Safe-start checks

(4) Ignition transformers

(5) Trial-for-ignition periods

(6) Excess-temperature controllers

(7) Valve-proving systems

8.4.2.9

A combustion safeguard should directly control at least one safety shutoff valvebetween the fuel gas supply and the monitored burner.

8.4.2.10

Where airflow-proving logic is performed in the PLC, the logic should include thefollowing:

(1) Verification of a change of state in each airflow-proving device during thestartup of the related ventilation equipment

(2) Initiation of a safety shutdown if a change of state in an airflow-proving deviceis not detected



(A) Access to the PLC and its logic shall be restricted toauthorized personnel.

(B) Software shall be documented as follows:

(1) Labeled to identify elements or group of elementscontaining safety software

(2) Labeled to describe the function of each element containingsafety software

(C) A listing of the program with documentation shall beavailable.

8.4.6 PLCs shall not implement the following:

(A) Manual emergency switches

(B) Continuous vapor concentration high limit controllers


This is a pending proposal by the Intro Chapters TG to NFPA 86-2011. If this proposal is not accepted, I my request is that section 8.4 be revised to duplicate the requirements in NFPA 86-2014.


Submitter FullName:

Ted Jablkowski




Committee Statement

















8.4.6

Where PLC-based systems use flow transmitters in place of flow switches andpressure transmitters in place of pressure switches for safety functions, thefollowing should apply:

(1) The transmitter should be listed, possess a minimum mean-time-between-failure rating of 250,000 hours, or possess a safety integrity level rating of 2.

(2) Upon transmitter failure, the PLC should detect the failure and initiate a safetyshutdown.

(3) The transmitter should be dedicated to safety service unless listed forsimultaneous process and safety service.


The deletion here is associated with Public Input No. 78-NFPA 87-2012.


Submitter FullName:

Ted Jablkowski




Committee Statement
















Public Input No. 73-NFPA 87-2012 [ Section No. 8.5.1.1 [Excluding any

Sub-Sections] ]

When a combustion air blower or exhaust blower is provided, a timed pre-ignitionpurge should be provided that incorporates all of the following:

(1) At least 4 standard cubic feet (scf) of fresh air or inert gas per cubic foot (4m3/m3) of system volume is introduced during the purging cycle.

(2) The system volume includes the heating chambers and all other passages thathandle the recirculation and exhaust of products of combustion.

(3) To begin the timed pre-ignition purge interval, both of the following conditionsare satisfied:

(a) The minimum required pre-ignition purge airflow is proved.

(b) The safety shutoff valve(s) is proved required by 8.7.2.2 are provedclosed.

(4) The minimum required pre-ignition purge airflow is proved and maintainedthroughout the timed pre-ignition purge interval.

(5) Failure to maintain the minimum required pre-ignition purge airflow stops thepre-ignition purge and resets the purge timer.


Possible conflict with 8.7.7.2 if under 400,000 Btu/h. Proved closed is not required when under 400,000 Btu/h.


Submitter FullName:

Ted Jablkowski




Affilliation: Similar public input developed in conjunction with NFPA 86 Intro ChaptersTask Group


Committee Statement


Statement: Possible conflict with 8.7.7.2 if under 400,000 Btu/h. Proved closed is not requiredwhen under 400,000 Btu/h. The committee also clarified the purge volumerequirement.












Public Input No. 38-NFPA 87-2012 [ Section No. 8.5.1.1.2 ]



8.5.1.1.2 2*

Repeating the pre-ignition purge can be omitted where any one of the followingconditions is satisfied:

(1) The heating chamber temperature is proved above 1400°F (760°C).

(2) For

any

(1) a multiburner fuel-fired system not proved above 1400°F (760°C) , all of thefollowing conditions are satisfied:

Each burner and pilot is supervised by a combustion safeguard in accordancewith Section 8.9 .

Each burner system is equipped with safety shutoff valves in accordance withSection 8.7 .

(1)(a) * At least one burner remains operating in the common combustionchamber of the burner to be re-ignited.

(b) The burner(s) remaining in operation shall provide ignition of any unintendedrelease of fuel through other burners that are not in operation withoutexplosion.

(3) * For fuel gas–fired burner systems and assuming that all safety shutoff valvesfail in the full open position, it can be demonstrated that the combustibleconcentration in the heating chamber and all other passages that handle therecirculation and exhaust of products of combustion cannot exceed 25 percent ofthe LFL.

(4) All of the following conditions are satisfied (does not apply to

liquidfuel oil systems):

Each burner and pilot is supervised by a combustion safeguard in accordancewith Section 8.9 .

Each burner system is equipped with gas safety shutoff valves in accordancewith Section 8.7 .

(a) The number of safety shutoff valves required to close in 8.7.1.2 and 8.7.1.3 willclose between a burner and the fuel gas supply when that burner is off.

(b) Safety shutoff valve seat leak testing is performed on at least a semiannualbasis.

(c) The burner system uses natural gas, butane, or propane fuel gas.

(d) * It can be demonstrated that the combustible concentration in the heatingchamber and all other passages that handle the recirculation and exhaust ofproducts of combustion cannot exceed 25 percent of the LFL.

(e) The minimum airflow used in the LFL calculation in 8.5.1.1.2(4)(d) is provedaccording to 8.6.5 and maintained during the period the burner(s) are off.







1. revise to be similar to NFPA 86-20112. revise (4)(e) adding "according to 8.6.5" since it is unclear if the “proved” requirement in 8.5.1.1.2(4)(e) is imposing a new requirement in addition to the requirement in 8.6.5. The proposal removes this ambiguity.


Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: The committee did not accept the recommendations because the 1400 degthreshold is not practical to maintain for the majority of fluid heaters. Option (3) isnot applicable to fluid heaters. It's a high excess air dryer application. Option (4) isdeleted because it would allow re-light without purge to occur when no flame ispresent.














Insert after 8.5.2 and renumber afterward.

8.5.2.1 Prior to the trial for ignition the logic solver in conjunction with the flamesafeguard shall perform a safe start check.


Substantiation for 8.5.2.1, 8.9.1 and Flame Response Time definition. The original definition of the combustion safeguard included a flame relay and all of the associated logic and the new



definition is just a flame sensor. The flame sensor cannot perform a safe start check as that is a logic function.I believe it was the intent of the code to mandate that the maximum time between the loss of flame and the de-energizing of the SSOVs to be 4 seconds. If that assumption is true then the flame scanner cannot consume all of the allotted time. Time must be left for the logic solver and interfacing logic to de-energize the safety shut-off valves.If the intent is to permit the flame sensor to take up to 4 seconds then we must decide what is a reasonable time for the logic solver to actuate the valves and for the valves to close.


Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: The committee did not the proposed language because the text is predicated onacceptance of the revised definition for combustion safeguard, which was also notaccepted by the committee.













Insert after 8.5.2 and renumber afterward .

8.5.2.1 Prior to the trial for ignition the logic solver in conjunction with theflame safeguard shall perform a safe start check.

8.5.2. 1

The trial-for-ignition period of the pilot burner should not exceed 15 seconds.






Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: The committee did not the proposed language because the text is predicated onacceptance of the revised definition for combustion safeguard, which was also notaccepted by the committee.















8.5.2.4

Electrical ignition energy for direct spark ignition systems should be terminatedafter the main burner trial-for-ignition period.

Where spark ignition systems cause a false flame signal, spark ignition must beterminated at the end of the trial for ignition period.

8.5.2.4.1 When combustion safeguards are not required, continuous operation of the sparkignition system shall be permitted.


Clarifies intent and removes violation of NFPA’s “manual of style” concerning exceptions. Note that the exception still exists with the phrase “in combustion safeguards where required”. Intent needed clarification because common understanding of direct spark burners versus piloted burners confuses the meaning of “direct spark ignition systems”. A user may assume that the spark can remain on throughout the pilot flame establishing period and then terminate after the main TFI period. Also, the user may assume that a piloted burner can have a spark that never terminates since this requirement applies to direct spark.


Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: There is no operation where combustion safeguards are not required. The proposedrevision does not add clarity or enhance safety.















8.7.1.3

In fuel gas systems or liquid fuel systems only, where multiple burners or pilotsoperate as a burner system firing into a common heating chamber, the loss of flamesignal at one or more burners should either comply with 8.7.1.2 or or shall shut offthose burner(s) by closing a single safety shutoff valve , where the followingconditions are satisfied: Individual burner as long as a second safety shutoff valvemeets one of the two following conditions:

(1) It is demonstrated, based on available airflow, that failure of the valve to closewill result in a fuel concentration not greater than 25 percent of the LFL.

(2) The safety shutoff valve has proof of closure acceptable to the authority havingjurisdiction.

The safety shutoff valve upstream of the individual burner safety shutoff valvesshould close between the fuel supply, and the burners shall close when any of thefollowing conditions occurs:(1) Upon activation of any

operating control or interlocking safety device other than the combustion safeguardsafety interlock common to the burner system

(2) * Where the individual burner safety shutoff valves do not have proof of closure

as described in 8.7.1.3 (1)(b) andand it is demonstrated, based on available airflow, that the number of failed burners

is capable of exceedingwill result in the furnace being above 25 percent of the LFL

if, assuming the single

-burner safety shutoff

valves failvalve(s) fails in the open position

(3) Where individual burner safety shutoff valves have proof of closure

as described in 8.7.1.3 (1)(b) and verification thatand any of the following conditions occurs:

(a) Where flame supervision is used, the individual burner safety shutoff valve

hasnot proved closed

followingafter loss of flame signal

at the burner is not present

(b) Where flame supervision is not used, the individual burner safety shutoff valvenot proved closed when the furnace is not proved to be above 1400°F (760°C)

(c) Upon loss of flame signal at all burners in the burner

system or at a number of burners in the burner system that will result in a fuel




concentration greater than 25 percent of the LFL

When the heating chamber is proved at or above 1400°F (760°C) and both of thefollowing conditions exist:

(1) Individual burners are shut off by closing a single safety shutoff valve equippedwith proof-of-closure switch and proved closed.

(2) If a burner is shut off by closing one safety shutoff valve and that safetyshutoff valve is not proved closed, a second safety shutoff valve upstreamcloses within 5 seconds.

system




Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: The subject text was deleted by FR-19.
















8.7.1.6 Safety shutoff valves shall not be open-close cycled at a rate that exceeds thatspecified by its manufacturer.


Same as NFPA86-2011.


Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: Added section to be consistent with NFPA86-2011.














Public Input No. 68-NFPA 87-2012 [ Section No. 8.7.2.2(A) ]

(A)

A proved closed condition should be accomplished by either of the following means:

(1) A proof-of-closure switch incorporated in a listed safety shutoff value assemblyin accordance with the terms of the listing

(2) A valve-proving system




Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: Same as NFPA 86-2011.















8.9.1

Each burner flame should have a combustion safeguard that has a maximum flamefailure flame response time of 4 seconds or less of less than 3.9 seconds , thatperforms a safe-start check, and that is interlocked into the combustion safetycircuitry in accordance with the following:

(1) The flame supervision is not needed in the combustion safety circuitry of afluid heater when the combustion chamber temperature is greater than 1400°F(760°C), and the following criteria are met:

(a) When the combustion chamber temperature drops to less than 1400°F(760°C), the burner is interlocked to allow its operation only if flamesupervision has been re-established.

(b) A 1400°F (760°C) bypass controller is used to meet the recommendationin 8.9.1(1)(a).

(2) The flame response time shall not exceed 4 seconds.

(3) Burners without flame supervision are interlocked to prevent their operationwhen the combustion chamber temperature is less than 1400°F (760°C) byusing a 1400°F (760°C) bypass controller.




Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: The committee struck (1) and (2) because 1400 deg F is impractical to maintain inmost fluid heaters.















8.9.1

Each burner flame should have a combustion safeguard that has a maximum flamefailure response time of 4 seconds or less, that performs a safe-start check, andthat is interlocked into the combustion safety circuitry in accordance with thefollowing:

(1) The flame supervision is not needed in the combustion safety circuitry of afluid heater when the combustion chamber temperature is greater than 1400°F(760°C), and the following criteria are met:

(a) When the combustion chamber temperature drops to less than 1400°F(760°C), the burner is interlocked to allow its operation only if flamesupervision has been re-established.

(b) A 1400°F (760°C) bypass controller bypass interlock is used to meetthe recommendation in 8.9.1(1)(a).

(2) Burners without flame supervision are interlocked to prevent their operationwhen the combustion chamber temperature is less than 1400°F (760°C) byusing a 1400°F (760°C) bypass controller interlock .


"controller" to "interlock" consistant with proposed add of 1400F Bypass Interlock as from NFPA 86-2011.


Submitter FullName:

Ted Jablkowski






Committee Statement

















8.9.1 1

8.9.1.1 Each burner flame

shouldshall have a combustion safeguard

that has a maximum flame failure response time of 4 seconds or less, that performsa safe-start check, and that is interlocked intoin the combustion safety circuitry

in accordance with the following:

The flame supervision is not needed in the combustion safety circuitry of a fluidheater when the combustion chamber temperature is greater than 1400°F (760°C),and the following criteria are met:

(1) When the combustion chamber temperature drops to less than 1400°F(760°C), the burner is interlocked to allow its operation only if flamesupervision has been re-established.

(2) A 1400°F (760°C) bypass controller is used to meet the recommendation in8.9.1 (1)(a).

Burners without flame supervision are interlocked to prevent their operation whenthe combustion chamber temperature is less than 1400°F (760°C) by using a1400°F (760°C) bypass controller.unless otherwise permitted in 8.9.1.2.

8.9.1.2 The following burner flames shall not require a combustion safeguard:

(1)Burner flames for radiant tube–type heating systems where a means of ignition isprovided and the systems are arranged and designed such that either of thefollowing conditions is satisfied:

(a)The tubes are of metal construction and open at one or both ends. If heatrecovery systems are used, they shall be of explosion-resistant construction.

(b)The entire radiant tube heating system, including any associated heat recoverysystem, is of explosion-resistant construction.

(2)Burner flames at burners interlocked with a 1400°F (760°C) bypass interlock thatprevents burner operation when the temperature in the zone where the burner islocated is less than 1400°F (760°C).

8.9.1.3* Where a combustion safeguard is required, the logic system shall:

(1) Have a maximum flame failure response time of 4 seconds or less

(2) Perform a safe-start check


Similar public input developed for NFPA86-2011. Objective is to re-organize the requirements for clarity. Not sure if NFPA 87 should indlue radiant tube type heating systems.


Submitter Full



Name: Ted Jablkowski




Committee Statement


















8.9.3 [old 8.9.1(1)] Where a combustion safeguard is required for a burner flame, flamesupervision shall not be required in the combustion safety circuitry of a furnace zone whenthat zone temperature is greater than 1400°F (760°C) and the following criteria are met:

(1)When the zone temperature drops to less than 1400°F (760°C), the burner is interlockedto allow its operation only if flame supervision has been re-established.

(2)A 1400°F (760°C) bypass interlock is used to meet the requirement of 8.10.3(1)


Similar public input developed for NFPA 86-2011. Related to comment to 8.9.1.


Submitter FullName:

Ted Jablkowski




Committee Statement


















8.10.2.1 The low pressure switch used to supervise the atomizing medium shall bepermitted to be located upstream of atomizing media balancing orifices and balancingvalves provided balancing devices are equipped with a locking device to prevent anunintentional change in the setting.


Taken from a public comment to move A.8.11.2.1 infomration into the mandatory text in NFPA 86-2014.


Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: Taken from a public comment to move A.8.11.2.1 infomration into the mandatorytext in NFPA 86-2014.












Public Input No. 75-NFPA 87-2012 [ New Section after 8.15 ]




8.16 1400°F (760°C) Bypass Interlock. 8.16.1 Where flame supervision is switched out of the combustion safety circuitry orunsupervised burners are brought on-line, as permitted by 8.9.1(1) or 8.9.1(3), a 1400°F(760°C) bypass interlock shall be used.8.16.2 Open circuit failure of the temperature-sensing components shall cause the sameresponse as an operating temperature less than 1400°F (760°C).8.16.3 * The 1400°F (760°C) bypass interlock shall be equipped with temperatureindication.8.16.4 * The temperature-sensing components of the 1400°F (760°C) bypass interlockshall be rated for the temperature and the atmosphere to which they are exposed.8.16.5 The temperature-sensing element of the 1400°F (760°C) bypass interlock shall belocated so that unsupervised burners are not allowed to operate at temperatures below1400°F (760°C).8.18.6 The 1400°F (760°C) bypass interlock set point shall not be set below 1400°F(760°C) and shall indicate its set point in units of temperature (degrees Fahrenheit ordegrees Celsius) that are consistent with the primary temperature-indicating controller.8.16.7 Visual indication shall be provided to indicate when the 1400°F (760°C) bypassinterlock is in the bypass mode.8.16.8* The operating temperature interlock and its temperature-sensing element shallnot be used as the 1400°F (760°C) bypass interlock.

A.16.8 An auxiliary contact in the Excess Temperature Limit Interlock device can be usedas a 1400F Bypass Interlock providing the requirements of 8.16.2 are satisfied.


Mandatory text is directly form NFPA 86-2011. 1400F bypass controller is used in 8.9.1. A.8.16.8 is a pending proposal to NFPA 86-2014.


Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: The committee did not accept the recommendation because the permissive for re-light without purge when a minimum temp of 1400 deg F is maintained was removedfrom 8.5.1.1.2.




















8.15.6 Except as allowed in 8.4, the operating temperature controller and its temperature-sensing element shall not be used as the excess temperature limit interlock.


From similar public comment to NFPA 86-2011, as related to the proposal to 8.4. This is a placeholder as a reminder that section 8.15 may need some changes to facilitate the desired implementation of the stack excess temperature interlock in a safety rated PLC.


Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: This is revised to be consistent with coverage for the excess fluid temperatureinterlock in 8.16.9.















8.16.9

The Except as allowed in 8.4, the operating temperature controller and itstemperature-sensing element should not be used as the fluid excess temperaturelimit interlock.


From similar public comment to NFPA 86-2011, as related to the proposal to 8.4. This is a placeholder as a reminder that section 8.16 may need some changes to facilitate the desired implementation of the stack excess temperature interlock in a safety rated PLC.


Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: The existing language is adequate.












Public Input No. 7-NFPA 87-2012 [ Chapter 9 ]


9.1 * General.



9.1 * General.

9.1.1

Class F heaters should be designed for relatively uniform fluid flow through paralleltube passes.

9.1.1.1

Equal flow distribution between passes should be ensured by piping geometry orfixed flow restrictions.

9.1.1.2

Adjustable balancing trim valves should not be used in multipass Class F heaters.

9.1.2

The maximum allowable bulk fluid temperature should be determined based on themaximum allowable fluid film temperature that will prevent rapid fluid degradation.

9.1.3

The heater manufacturer should determine the minimum flow rate, taking intoconsideration the maximum allowable bulk fluid temperature and the maximum heatinput rate.

9.1.4

Where backflow into the heater presents a hazard, a means to prevent backflowshould be provided.

9.1.5 *

The fluid system should be designed so that fluid cannot be trapped in the heatedzone.

9.1.6 *

The fluid system should be designed to maintain at least the minimum required fluidflow through the heater under all operating conditions.

9.1.7

An expansion tank should be provided for all closed-loop liquid circuits.

9.1.8

A manual emergency switch should be provided to initiate a safety shutdown of theentire fluid heater system at a remote location.

9.2 Auxiliary Equipment.

9.2.1 Pumps.

9.2.1.1 *

Air-cooled or water-cooled pumps with mechanical seals or magnetically coupled(seal-less) pumps should be used.

9.2.1.2

The system should be designed such that there is sufficient net positive suctionhead available for the pump.

9.2.1.3

Positive displacement pumping systems should incorporate features to ensure thatthe minimum flow through the heater is maintained.

9.2.1.4 *

The pumps should be compatible with the fluid used as well as the operatingpressures and temperatures.

9.2.1.5 *

If water-cooled pumps are used, a means of verifying cooling water flow should beprovided.

9.2.1.6 *



9.2.1.6 *

Cold alignment of air- and water-cooled pumps should be done in accordance withthe pump manufacturer’s recommendations prior to the pump being started.

9.2.1.7 *

Hot alignment of air- and water-cooled pumps should be done within the first 24hours after operating temperature has been reached.

9.2.1.8

Cold and hot alignment should be performed during commissioning and followingpump maintenance.

9.2.2 Catch Tank.

9.2.2.1

The effluent from all pressure relief devices, vents from the expansion tank, anddrains from the expansion tank should be directed to a closed catch tank.

9.2.2.2

The catch tank should have a vent to atmosphere, with the vent outlet located at anapproved location outside the heater room.

9.2.2.3

The vent should be adequately sized to handle 150 percent of the maximum flowfrom the heater relief device.

9.2.2.4

If the fluid being relieved is combustible, a flame arrester should be located in thevent line.

9.2.2.5

The contents should not be reused in the fluid heating system.

9.2.2.6

The catch tank inlets should be located to prevent siphoning of the contents backinto the system.

9.2.2.7

A liquid level indicator should be provided on the tank.

9.2.3 Strainers.

9.2.3.1

One strainer should be placed in the suction piping of each pump.

9.2.3.2 *

A minimum 60 mesh stainless steel strainer element should be used.

9.2.3.3

Isolation valves should be placed in the suction and discharge piping of the pump tofacilitate cleaning of the strainer.

9.2.3.4

A means should be provided to drain the strainer prior to cleaning.

9.2.3.5

A pressure gauge should be placed between the strainer and the pump inlet toindicate strainer blockage.

9.2.4 Valves.

9.2.4.1

Gate valves should be used for isolation purposes.

9.2.4.2

Globe valves or wafer valves should be used for throttling purposes.



9.2.4.3 *

Valves should be compatible with the fluid being used and the system operatingtemperatures and pressures.

9.2.4.4

Where used, automatic process equipment bypass valves should fail open uponpower loss.

9.2.5 Expansion Tanks.

9.2.5.1

The expansion tank should be connected to the fluid system piping upstream of thefluid pump.

9.2.5.2 *

The expansion tank should be compatible with the fluid being used and the systemoperating temperatures and pressures.

9.2.5.3 *

The expansion tank should be sized to accommodate the fluid expansion in theentire system.

9.2.5.4

A low level switch should be provided.

9.2.5.4.1

The low level switch should be satisfied before the pumps and the heater can bestarted.

9.2.5.4.2

The low level switch should be interlocked to shut down the pump and heater if alow level occurs.

9.2.5.5

An expansion tank drain should be provided.

9.2.5.6

A means for sampling for water contamination should be provided at the low point ofthe expansion tank.

9.2.5.7

Local or remote indication of tank level should be provided.

9.2.5.8

Expansion tanks should be vented to the catch tank.

9.2.5.9 *

An expansion tank pressurized with an inert gas should be used if any of thefollowing conditions exists:


(2) The tank contents can be at a temperature such that exposure of the fluid toair would cause degradation of the fluid.





9.2.5.10

All pressurized expansion tanks should be equipped with a pressure relief devicepiped to the catch tank.

9.2.5.11

All expansion tanks that are pressurized over a gauge pressure of 15 psi (100 kPa)should meet the requirements of ASME Section VIII Division 1.

9.2.5.12

Pressurized expansion tanks should have a low inert gas pressure alarm set at avalue determined by the fluid supplier.

9.3 Safety Devices for Class F Heaters.

9.3.1 Low Fluid Flow.

9.3.1.1 *

Means should be provided to prove minimum fluid flow through the heater at alloperating conditions.

9.3.1.2

The minimum flow–proving device should be interlocked into the combustion safetycircuitry.

9.3.1.3

Means should be provided to prove minimum fluid level in the expansion tank at alloperating conditions.

9.3.2 Interlocks.

The combustion safety circuitry should incorporate the following interlocks:

(1) High stack temperature located upstream of the stack damper

(2) High process outlet temperature

(3) Process low flow limit


Additional Proposed Changes

File Name Description Approved

Public Input attachment PI-7-NFPA 87-2012 (Chapter 9 2012Rev1).pdf


Chapter 9 is deleted in its entirety to allow insertion of new Chapter 9 (complete), which is provided in the attachment to this Public Input submission. Chapter 9 has been revised in its entirety to correlate with newly added Chapter 10.








Committee Statement


Statement: Chapter 9 is deleted in its entirety to allow insertion of new Chapter 9 (complete),which is provided in the attachment to this Public Input submission. Chapter 9 hasbeen revised in its entirety to correlate with newly added Chapter 10.















9.2.5.12

Pressurized expansion tanks should have a low inert gas pressure alarm set at avalue determined by with input from the fluid supplier, and in consideration ofcirculation pump NPSH requirements .


The fluid supplier could not be expected to have the detailed knowledge of the design of the system, and possibly not the engineering expertise necessary to recommend the proper inert gas pressure above the liquid in the expansion tank. This should be left to the system designer.


Submitter Full Name:Gamble Conrad

Organization: Solutia Inc.

Submittal Date: Mon Mar 26 10:03:25 EDT 2012

Committee Statement


Statement: Chapter 9 is deleted in its entirety to allow insertion of new Chapter 9 (complete),which is provided in the attachment to this Public Input submission. Chapter 9 hasbeen revised in its entirety to correlate with newly added Chapter 10.


I, Gamble Conrad, hereby irrevocably grant and assign to the National Fire Protection Association (NFPA) all and






By checking this box I aff irm that I am Gamble Conrad, and I agree to be legally bound by the above








10.1 * General. (Reserved)

10.2 Auxiliary Equipment. (Reserved)

10.3 Safety Devices for Class G Heaters. (Reserved)



Public Input attachment PI-8-NFPA 87-2012 (Draft 87 Chapter 10Rev4B).pdf


New required and annex text for Class G fluid heaters, generated to replace reserved space.






Committee Statement


Statement: New required and annex text for Class G fluid heaters, generated to replacereserved space. FR-60-NFPA 87-2012, contains the new annex for this chapter.
















11.1 * General. (Reserved)


11.3 Safety Devices for Class H Heaters. (Reserved)

(see attached PDF document)



Draft 87 Chapter 112012 Rev0.pdf

Draft content for Chapter 11 (Class H Fluid Heaters) - to be reviewed prior to 1st Draft Meeting


The NFPA 87 Technical Committee wishes to compile a "complete" version of the Recommended Practice during the current cycle so that the public can review and get to know the RP over the next four years, and provide input to the committee on all three types of fluid heaters (Class F, G, and H) before the following edition is put up for consideration as a Standard (instead of an RP).

Chapter 11 will contain the guidelines for Class H fluid heaters.




Affilliation: Secretary of the NFPA 87 Technical Committee

Submittal Date: Wed Jun 20 17:59:10 EDT 2012

Committee Statement


Statement: The NFPA 87 Technical Committee wishes to compile a "complete" version of theRecommended Practice during the current cycle so that the public can review andget to know the RP over the next four years, and provide input to the committee onall three types of fluid heaters (Class F, G, and H) before the following edition is putup for consideration as a Standard (instead of an RP). See FR-61-NFPA 87-2012 forthe added annex material.









Public Input No. 21-NFPA 87-2012 [ New Section after A.3.3.29.5 ]


A.3.3.4 Burner Management System. The burner management system logic can includethe following functions safety interlocks, pre-purge, trial for ignition, and safe-start check.




Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: The annex information does not provide clarity or explanation beyond what isprovided in the definition.












Public Input No. 17-NFPA 87-2012 [ New Section after A.5.3 ]



Public Input No. 17-NFPA 87-2012 [ New Section after A.5.3 ]

Add text to read as follows: A.5.3 Damage-limiting construction could include exterior panels that are designed tobecome detached under the influence of internal pressure from a deflagralion. In suchcases, tethering the panels is vitally important to ensure dislodged panels don't causeinjury or damage. NFPA 68 provides guidance for tethering doors and walls that canbecome dislodged in a deflagration event.


Fluid heaters are generally not designed to withstand internal pressures developed by a deflagration. As such, containment and explosion suppression are likely not viable options. Location is not an ideal solution, because it is impossible to ensure personnel will never be working in the area of an operating fluid heater. .. especially during startup and shutdown. By combining tethers with a -damage limiting construction" approach, the traditional design features of many fluid heaters can be made safer.




Submittal Date: Thu May 24 14:02:02 EDT 2012

Committee Statement


Statement: Fluid heaters are generally not designed to withstand internal pressures developedby a deflagration. As such, containment and explosion suppression are likely notviable options. Location is not an ideal solution, because it is impossible to ensurepersonnel will never be working in the area of an operating fluid heater especiallyduring start-up and shutdown. By combining tethers with a -damage limitingconstruction" approach, the traditional design features of many fluid heaters can bemade safer.














Public Input No. 5-NFPA 87-2012 [ Section No. A.5.5.1.3 ]

A.5.5.1.3

Flanged and threaded connections are not recommended for flammable orcombustible liquids due to possible leakage. Threaded connections in the flowcircuit typically are not used on piping greater than 1 in. (25 mm) NPT. Additionalguidance can be found in ASME B31.3.


This explanatory input and the new text (5.5.1.3 and subsections) clarifies the committee's intent that welded connections should be used as often as is practical.






Committee Statement


Statement: This explanatory input and the new text (5.5.1.3 and subsections) clarifies thecommittee's intent that welded connections should be used as often as is practical.














Public Input No. 14-NFPA 87-2012 [ New Section after A.7.5.17 ]

A.7.5.22

See A.6.2.7.3.


New annex text submitted for consistency with NFPA 86 TIA 11-3.






Committee Statement
















Public Input No. 36-NFPA 87-2012 [ Section No. A.8.2.9 ]

A.8.2.9

For some applications, additional manual action might be required to bring theprocess to a safe condition.The actions resulting from a manual emergency switchaction take into account the individual system design and the hazards (e.g.mechanical, combustion system, special atmosphere, etc.) associated withchanging the existing state to another state and initiates actions to cause thesystem to revert to a safe condition.


The 2011 Edition’s implies there is to be a single manual emergency switch. Depending upon the type of furnace there maybe multiple manual emergency switches to address the multiple “safety” hazards of the furnace. All of the furnace’s safety hazards should be evaluated and a manual emergency “system” should be designed/incorporated into the furnace design.


Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: Annex text was added to further clarify the document text.














Public Input No. 27-NFPA 87-2012 [ Section No. A.8.3 ]

A.8.3

Furnace controls that meet the performance-based requirements of standards suchas ANSI/ISA 84.00.01, Application of Safety Instrumented Systems for the ProcessIndustries, and IEC 61511 Functional Safety: Safety Instruments Systems for theProcess Industry Sector can be considered equivalent. The determination ofequivalency involves complete conformance to the safety life cycle, including riskanalysis, safety integrity level selection, and safety integrity level verification, whichshould be submitted to the authority having jurisdiction.


IEC61511 is exactly equivalent to ANSI/ISA84.00.01.


Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: IEC61511 is exactly equivalent to ANSI/ISA84.00.01.














Public Input No. 39-NFPA 87-2012 [ New Section after A.8.5.1.2(1) ]


A.8.5.1.1.2 The following sections of this standard continue to apply where the provisionsof 8.5.1.2.1 are applied:

(1) The combustion air safety device requirements of Section 8.6.

(2) Each burner and pilot is supervised by a combustion safeguard in accordancewith Section 8.9.

(3) Each burner system is equipped with safety shutoff valves in accordance withSection 8.7.


Add Annex per NFPA 86-2011.


Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: The committee requests the submitter to clarify the recommendation. Thecommittee could not determine how the proposed annex material relates to the textin the body of the document.




















A.8.5.1.2.1(3) Consideration should be given to the proximity of operating burners when thecommon combustion chamber exception to repeating purges is utilized. Accumulation oflocalized vapors or atmospheres is possible even with an operating burner in a chamber,depending on the size of the chamber, the number of burners, and the proximity ofoperating burners to the accumulation. In addition to proximity, burner design andexposure of the flame may also impact the ability of the operating burner to mitigate vaporor gaseous accumulations.


Add Annex as per NFPA 86-2011.


Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: Annex material is added to be consistent with NFPA 86-2011.
















A.8.5.1.2.1(3)

The following sample calculation is provided to demonstrate a method of determining the25 percent LFL requirement. The calculation is based on the following assumptions:

(1) The fuel is methane gas.

(2) All burners are off, and all safety shutoff valves are de-energized.

(3) All burner safety shutoff valves fail to function and remain full open during theperiod that the burners are off.

(4) Safety shutoff valve leakage is equal to the maximum burner fuel input rate.

Overall, the sample calculation is based on the following conservative conditions:

(1) The use of the maximum fuel input rate for each burner

(2) Failure of all burner safety shutoff valves fail to close

(3) Design limit of 25 percent of LFL

(4) Inclusion of the effects of elevated furnace temperature on the LFL

The effects of temperature on fuel gas LFL were obtained from Bureau of Mines Bulletin680, “Investigation of Fire and Explosion Accidents in the Chemical, Mining, and Fuel-Related Industries — A Manual.” Figure 34 in that bulletin, “Temperature effect on lowerlimits of flammability of 10 normal paraffins in air at atmospheric pressure,” showstemperature (°C) versus combustibles (volume percent) and includes curves for methane,butane, and propane. It also includes a formula for computing LFL at elevated temperature.That formula, from Bureau of Mines Bulletin 627, “Flammability Characteristics ofCombustible Gases and Vapors,” as follows:

where:LT = LFL at the desired elevated temperature,T (°C)

L 25 = LFL at 25°C

T = Desired elevated temperature (°C)

Sample Problem — U.S. Customary Units Objective. Calculate the airflow rate moving through the oven enclosure to maintain theoven atmosphere at or below 25% LFL.Given the following information:

(1) Oven type: Continuous

(2) Fuel: Methane

(3) Number of burners: 5

(4) Maximum fuel input per burner: 1000 scfh

(5) Oven temperature: 275°F

(6) Exhaust airflow rate: 10,000 cfm



Step 1. Determine LFL at 275°F using the formula from Bureau of Mines Bulletin 627:


Add Annex per NFPA 86-2011


Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: The annex text is not accepted because the subject paragraph was deleted in FR-18.














A.8.5.1.1.2 (4)(d) In accordance with 8.5.1.8(4)(c), fuels other than natural gas, butane, orpropane may require additional consideration. These additional considerations would beaddressed using Section 1.5. The concern with other fuel gases is the variability of fuel gascontent being delivered over time. Specific examples include landfill gas and bio gas.The following sample calculation illustrating the use of 8.5.1.8(4)(d) is provided todemonstrate a method of determining the 25% LFL requirement.The sample calculation is based upon the following assumptions:

(1) The fuel is methane gas.






(2) All burners are turned off for the control purposes. All safety shutoff valves arede-energized.

(3) Two safety shutoff valves are closed at each burner.

(4) All safety shutoff valves are proven closed.

(5) All safety shutoff valves are tested for seat leakage at least semiannually.

(6) Safety shutoff valve seat leakage is assumed to be 1 scfh (0.0283 m3/hr @21°C).

The following thoughts are offered regarding the selection of the 1 scfh (0.0283 m3/hr @21°C) safety shutoff valve seat leakage rate.Limited data reviewed by the committee indicates that valve seat leakage rates over 1 scfh

(0.0283 m3/hr @ 21°C) are not anticipated unless the safety shutoff valve seats areexposed to extremely unusual conditions such as corrosives in the fuel gas or furnaceheat allowed to back up the fuel line and burn the safety shutoff valve seat. The formercondition is the basis for limiting the use of 8.5.1.8(4) to furnaces using natural gas,butane, or propane fuel gases. The latter condition occurred in a case where a fuel linewas inappropriately opened by maintenance staff while the furnace was in operation. Thefurnace was promptly shut down, and the safety shutoff valves were replaced.Under operating conditions expected by this standard, it is anticipated that debris frominternal fuel gas line oxidation (rust), pipe thread shavings not removed before fuel lineassembly, or similar exposures can subject one safety shutoff valve to seat damage thatcan lead to seat leakage of one safety shutoff valve; however, it is not expected that bothsafety shutoff valves would experience similar seat leakage. The selected safety shutoff

valve seat leakage rate of 1 scfh (0.0283 m3/hr @ 21°C)is considered conservative.Overall, this sample calculation is based upon the following conservative conditions:

(1) The use of a 1 scfh (0.0283 m3/hr @ 21°C) safety shutoff valve seat leakagerate.

(2) Providing two safety shutoff valves for each fuel path.

(3) Using valve proving to prove each safety shutoff valve closed.

(4) Assuming safety shutoff valve leakage at each burner fuel path.

(5) Using a design limit of 25 percent of LFL.

(6) Including the effects of elevated furnace temperature on the LFL.

(7) Assuming no fuel exits the furnace.

The effects of temperature on fuel gas LFL were obtained from a United States Departmentof the Interior, Bureau of Mines Bulletin 680, “Investigation of Fire and Explosion Accidentsin the Chemical, Mining, and Fuel-Related Industries — A Manual.” Figure 34 in thatbulletin, “Temperature effect on lower limits of flammability of 10 normal paraffins in air atatmospheric pressure,” shows temperature (°C) versus combustibles (volume percent) andincludes curves for methane, butane, and propane. It also includes a formula for computingLFL at elevated temperature. That formula, based on Bureau of Mines Bulletin 627,“Flammability Characteristics of Combustible Gases and Vapors,” is as follows:

where:LT = LFL at the desired elevated temperature, T (°C)

L25 = LFL at 25°C




L25 = LFL at 25°C

T = Desired elevated temperature (°C)

Sample Problem — U. S. Customary Units Objective. Calculate the amount of time that all burners can be turned off before thefurnace atmosphere will reach 25% of LFL.Assumptions. Furnace contains no combustibles when the burners are turned off. Furnaceis under positive pressure with no air infiltration.Given the following information:Furnace type: BatchFurnace size: 8 ft wide × 6 ft deep × 8 ft tallNumber of burners: 5Burner design rate: 0.8 MM Btu/hrBurner design excess air: 10.0%Burner design air capacity: 8800 scfhBurner air minimum design flow: 100 scfhMaximum leak rate each flow path*: 1 scfhNumber of burner flow paths**: 5Furnace temperature: 900°F or 482°COxygen in furnace atmosphere: 18%Fuel: Methane*The flow path is across one set of safety shutoff valves proven closed.**The number of flow paths is the number of sets of safety shutoff valves proven closed thatmay leak into the furnace enclosure.Step 1. Determine LFL at 900°F using the formula from above:

Step 2. Determine the furnace volume:


Add Annex per NFPA 86-2011.


Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: The committee did not make the recommended changes to the body of thedocument, therefore the related annex text is not applicable.














Public Input No. 45-NFPA 87-2012 [ Section No. A.8.6.5 ]

A.8.6.5

In industrial combustion applications with modulating flow control valvesdownstream of the combustion air blower, it is most common to interlock theconstant combustion air source pressure on single-burner and multiburner systemsto meet the recommendations of 8.6.3 and 8.6.5.

Because the combustion airflow is proved during each purge cycle along with thecombustion air source pressure, the most common convention is to prove thecombustion air source pressure during burner operation following purge. In amultiburner system, the proof of combustion airflow during purge proves that anymanual valves in the combustion air system are in an adequately open position.These manual air valves are provided for maintenance and combustion airflowbalancing among burners in a temperature control zone. In combustion air supplysystems that use either an inlet damper or a speed control, the combustion airpressure can fall below reliably repeatable levels with listed pressure switchinterlocks at low fire. For these systems, the proof of minimum airflow can be amore reliable interlock.

A pressure switch on the inlet (suction) side of an Induced Draft (I.D.) fan can beused to prove that the minimum required suction pressure is available.

For combustion systems that use high pressure gas/air to induce (inspirate) airlocally at each burner, it is impractical to monitor and prove the availability ofcombustion air.

For combustion systems that use Natural (stack) Draft to induce air into theburners or combustion chamber, it is impractical to monitor and prove theavailability of combustion air.


Adds clarifying content to the Annex to help users differential between sources of combustion air for which minimum flow or pressure can be proven and soruces for which it cannot, practically speaking.


Submitter FullName:

Ted Jablkowski






Committee Statement


Statement: The revision explains several methods for proving the minimum combustion airflow.














A.8.7.1.3 Paragraph 8.7.1.3 addresses conditions under which only one safety shutoffvalve is to close to isolate a burner from its fuel gas supply. Figure A.8.7.1.3 provides asummary of 8.7.1.3 in the form of a decision tree. See 8.5.1.1.2 for guidance regardingconditions that are needed to allow that burner to be placed back in service. Therequirements of 8.5.1.1.2 might not allow a burner shut off by closing a single safetyshutoff valve to be placed back in service without repeating a pre-ignition purge.The requirements of 8.7.1.3 do not preclude opening of the safety shutoff valve locatedupstream of the individual burners using single safety shutoff valves during the trial forignition for the first burner being lighted.

(copy and add Figure A.8.8.1.3 from NFPA 86-2011 and label Figure A.8.7.1.3 SafetyShutoff Decision Tree)


Sames as NFPA 86-2011.


http://codesonline.nfpa.org/NFPA/a/c.html/nfpa_86_2011#2011_G86-74








Submitter FullName:

Ted Jablkowski




Committee Statement
















Add new Figure: (could not attach it here)

Figure A.8.7.2.2 Example for Multiple Burner System with independently operatedburners using a Common SSOV with single Proved Closed Interlock for Pre-purge

* Indicates a Proof of Closure switch. A Valve Proving system may also be an option.

** Indicates Position Indication. Where the individual burner inputs are under 150,000Btu/h, Position Indication is not required.



PI 74 - NFPA 87-2012 figure for A 8 7 2 2 finaltj120622.docx




Add clarification that 8.8.2.2 does not require more than one proved closed interlock for pre-purge in a multi-burner system.Figure will be sent separately to Derek Duval.


Submitter FullName:

Ted Jablkowski




Committee Statement

Resolution: The committee believes that two safety shutoff valves should be required for everyburner, therefore the diagram is not applicable.
















A.8.9.1.3 Subsections 8.2.3 and 8.2.6 require that the flame detector and the combustionsafeguard be applied and installed according to the manufacturer’s instructions. Whereflame detectors (scanners) with combustion safeguards that continuously operate withouta shutdown beyond the maximum interval recommended by the combustion safeguard andflame detector manufacturer's instructions, continuous operation without a shutdown andsafe-start check would not be compliant.


Similar public input developed for NFPA 86-2011. See related proposal to 8.9.1.


Submitter FullName:

Ted Jablkowski




Committee Statement


Statement: The statement is added to reinforce compliance with manufacturer's instructions.












First Revision No. 62-NFPA 87-2012 [ New Section after 2.3.3 ]


2.3.4 IEC Publications.

International Electrical Commission, 3 rue de Varembé, P.O. Box 131, CH - 1211, Geneva 20,Switzerland.

IEC 61511, Functional Safety: Safety Instruments Systems for the Process Industry Sector, 2004.


Submitter Full Name: Derek Duval

Organization: National Fire Protection Assoc

Street Address:

City:

State:

Zip:

Submittal Date: Fri Nov 30 08:54:45 EST 2012

Committee Statement

Committee Statement: Added this reference in FR-49-NFPA 87-2012.

Response Message:

Ballot Results

This item has passed ballot

21 Eligible Voters

1 Not Returned

19 Affirmative All

0 Affirmative with Comments

0 Negative with Comments

1 Abstention

Not Returned

Wechsler, Tom

Affirmative All

Abstention

Mooney, Mark F.

It pulls up a blank box when I click to review it.

National Fire Protection Association Report http://submittals.nfpa.org/TerraViewWeb/ContentFetcher?commentPara...

1 of 302 7/7/2014 1:44 PM

First Revision No. 1-NFPA 87-2012 [ Section No. 2.3.4 ]

2.3.5 UL Publications.

Underwriters Laboratories Inc., 333 Pfingsten Road, Northbrook, IL 60062-2096.

UL 795, Standard for Commercial-Industrial Gas Heating Equipment, 2006 2011 .


Submitter Full Name: [ Not Specified ]

Organization: [ Not Specified ]

Street Address:

City:

State:

Zip:

Submittal Date: Thu Oct 25 12:45:00 EDT 2012

Committee Statement

Committee Statement: Update referenced standard to most recent edition as indicated.

Response Message:

Public Input No. 16-NFPA 87-2012 [Section No. 2.3.4]

Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom

Affirmative All


2 of 302 7/7/2014 1:44 PM



3.3.4 Burner Management System.

The field devices, logic system, and final control elements dedicated to combustion safety and operatorassistance in the starting and stopping of fuel preparation and burning equipment and for preventingmisoperation of and damage to fuel preparation and burning equipment.




Street Address:

City:

State:

Zip:


Committee Statement

CommitteeStatement:

The term Burner Management System is used to describe the Logic Systems described insection 8.3. The definition proposed is directly from NFPA 85-2011. The annex material proposedis new for NFPA 87.

ResponseMessage:

Public Input No. 20-NFPA 87-2012 [New Section after 3.3.3]

Ballot Results


21 Eligible Voters

1 Not Returned

19 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom

Affirmative All

Affirmative with Comment

Martin, Richard J.

This new definition was taken from NFPA 85, which covers gas-, liquid-, and solid-fuel burners. Since NFPA 87presently does not cover solid-fuel combustion systems, the Technical Committee should consider revising thelanguage of this first revision to exclude "fuel preparation".


3 of 302 7/7/2014 1:44 PM

First Revision No. 2-NFPA 87-2012 [ New Section after 3.3.7.2 ]

3.3.9 Emergency Shutoff Valve.

A manual shutoff valve to allow the fuel to be turned off in an emergency.

3.3.10 Equipment Isolation Valve.

A manual shutoff valve for shutoff of the fuel to each piece of equipment.




Street Address:

City:

State:

Zip:


Committee Statement

CommitteeStatement:

Same as NFPA 86-2011. The terms are defined to distinguish between two valves that havedifferent purposes and requirements.

ResponseMessage:

Public Input No. 53-NFPA 87-2012 [New Section after 3.3.7.2]

Ballot Results


21 Eligible Voters

1 Not Returned

19 Affirmative All



1 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All

Abstention

Mooney, Mark F.

Nothing to view.


4 of 302 7/7/2014 1:44 PM


3.3.11 Explosive Range. Flammable Limit.

The range of concentration of a flammable gas in air within which a flame can be propagated, with thelowest flammable concentration known as the lower explosive limit (LEL) flammable limit (LFL) , and thehighest flammable concentration known as the upper explosive limit (UEL) flammable limit (UFL) .




Street Address:

City:

State:

Zip:


Committee Statement

Committee Statement: Revised to be consistent with NFPA 86-2011.

Response Message:


Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


5 of 302 7/7/2014 1:44 PM



3.3.17* Hardwired.

The method of interconnecting signals or interlocks to a logic system or between logic systems using adedicated interconnection for each individual signal.




Street Address:

City:

State:

Zip:

Submittal Date: Fri Oct 26 14:54:34 EDT 2012

Committee Statement

CommitteeStatement:

“Hardwired” is used in NFPA 87 and not defined. Definition is from NFPA 85-2011. New definitionthat is not replacing any current definition, renumber subsequent sections. See FR-63-NFPA87-2012 for the annex material for this FR.

ResponseMessage:


Ballot Results


21 Eligible Voters

1 Not Returned

19 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All

Negative with Comment

Tanguay, Francois

This Hardwired definition does not include the full content of the one found in NFPA 85 and it should, as it unclearconcerning the 'logic system' wiring aspect. The NFPA 85 'logic system' definition should also be added to NFPA87 if the above revised definition of hardwired is being used. NFPA 85 3.3.95 Logic System. A system thatprovides outputs in a particular sequence in response to external inputs and internal decision-making elements.Additionally, the FR-49 includes some explanation of the intent of the committee which makes it unclear aboutlogic system being included in hardwired system. FR-49 explanation: The intent of the committee is to ensure that


6 of 302 7/7/2014 1:44 PM

at least one emergency shutdown switch is hardwired and operational without use of a PLC or other logic. I can'tfind a better definition for 'hardwired', but the one proposed is not clear to me.


7 of 302 7/7/2014 1:44 PM


3.3.20 Manufacturer.

The entity that directs and controls any of the following: product design, product manufacturing, orproduct quality assurance; or the entity that assumes the liability for the product or provides thewarranty for the product.




Street Address:

City:

State:

Zip:


Committee Statement

CommitteeStatement:

The committee added a definition for manufacturer to clarify the usage within the context ofNFPA 87. This is not replacing any current definitions, renumber subsequent sections.

ResponseMessage:

Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


8 of 302 7/7/2014 1:44 PM

First Revision No. 23-NFPA 87-2012 [ Section No. 3.3.15, 3.3.20 ]

3.3.19 Lower Explosive Limit (LEL). Flammable Limit (LFL).

See 3.3.8 3.3.11 , Explosive Range Flammable Limits .




Street Address:

City:

State:

Zip:


Committee Statement

CommitteeStatement:

Revised to be consistent with NFPA 86-2011. Replace LEL with LFL throughoutdocument.

Response Message:


Ballot Results


21 Eligible Voters

1 Not Returned

19 Affirmative All



1 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All

Abstention

Mooney, Mark F.

No link to view the document.


9 of 302 7/7/2014 1:44 PM

First Revision No. 3-NFPA 87-2012 [ Section No. 3.3.30.1 ]

3.3.35.1 Catch Tank.

A tank used to capture liquid from drains, relief valves, vents, and overflows.




Street Address:

City:

State:

Zip:


Committee Statement

Committee Statement: Text deleted because term is no longer used in the document.

Response Message:

Public Input No. 1-NFPA 87-2012 [Section No. 3.3.30.1]

Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


10 of 302 7/7/2014 1:44 PM



4.1.3.2

Where seal leakage or diaphragm failure in a device can result in flammable gas or flammable liquidflow through a conduit or cable to an electrical ignition source, a conduit seal or a cable type that issealed should be installed.




Street Address:

City:

State:

Zip:


Committee Statement


Response Message:


Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


11 of 302 7/7/2014 1:44 PM


5.1.4.1

Fluid heaters should be located with space Space should be provided above and on all sides forinspection and maintenance , maintenance, and operational purposes.




Street Address:

City:

State:

Zip:


Committee Statement

CommitteeStatement:

The Committee believes that space required for explosion venting and sprinklers is coveredby NFPA 68 and NFPA 13, respectively.

ResponseMessage:


Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


12 of 302 7/7/2014 1:44 PM


5.4.3.3*

Where ducts pass through fire resistance–rated or noncombustible walls, floors, or partitions, the spacearound the duct should be sealed with a material that will noncombustible material to maintain thefire-resistance rating of the barrier.




Street Address:

City:

State:

Zip:


Committee Statement


Response Message:


Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


13 of 302 7/7/2014 1:44 PM


5.4.3.11

Exhaust ducts should not discharge near openings or other air intakes where effluents can enter abuilding. be entrained and directed to locations creating a hazard.




Street Address:

City:

State:

Zip:


Committee Statement

Committee Statement: Revise to be consistent with NFPA 86-2011.

Response Message:


Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


14 of 302 7/7/2014 1:44 PM


5.5.1.3*

Flanged and threaded connections in the flow circuit should be minimized. In applications where fluidleakage creates a hazard, all pipe connections should be welded.

5.5.1.3.1

Flange connections should be limited to pump, valve, boundary limit, spool, and equipmentconnections.

5.5.1.3.2

Threaded connections should be limited to instruments and other miscellaneous connections less than1 in. (25 mm).




Street Address:

City:

State:

Zip:


Committee Statement

CommitteeStatement:

This revision and the new subtext (5.5.1.3.1 and 5.5.1.3.2) clarifies the Committee's intent thatwelded connections should be used as often as is practical.

ResponseMessage:




Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


15 of 302 7/7/2014 1:44 PM


6.2.4.1*

A remotely located shutoff valve should be provided to allow the fuel to be turned off in an emergencyand should be located so that fire or explosion at the fluid heater does not prevent access to the valve.An emergency shutoff valve should be provided that meets the following requirements:

(1) It should be remotely located away from the fluid heater so that fire or explosion at a fluid heaterdoes not prevent access to the valve.

(2) It should be readily accessible.

(3) It should have permanently affixed visual indication of the valve position.

(4) A removable handle should be permitted provided all the following requirements are satisfied:

(a) The valve position is clearly indicated whether the handle is attached or detached.

(b) The valve handle is tethered to the gas main no more than 3 ft (1 m) from the valve in amanner that does not cause personnel safety issues and that allows trouble-freereattachment of the handle and operation of the valve without untethering the handle.

(5) It should be able to be operated from full open to full close and return without the use of tools.




Street Address:

City:

State:

Zip:


Committee Statement

Committee Statement: Revised for consistency with NFPA 86.

Response Message:


Ballot Results


21 Eligible Voters

1 Not Returned

19 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,


16 of 302 7/7/2014 1:44 PM

Affirmative All


Hudson , James G.

An approved emergency shutoff valve.....


17 of 302 7/7/2014 1:44 PM



6.2.4.4

An equipment isolation valve should be provided.




Street Address:

City:

State:

Zip:


Committee Statement


Response Message:


Ballot Results


21 Eligible Voters

1 Not Returned

19 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


Hudson , James G.

An approved equipment isolation valve....


18 of 302 7/7/2014 1:44 PM


6.2.5.1 Equipment Isolation Valves.

Individual manual shutoff valves for equipment isolation should be provided for shutoff of the fuel to eachpiece of equipment. Equipment isolation valves should meet the following requirements:

(1) They should be provided for each piece of equipment.

(2) They should have permanently affixed visual indication of the valve position.

(3) They should be quarter-turn valves with stops.

(4) Wrenches or handles should remain affixed to valves and should be oriented with respect to thevalve port to indicate the following:

(a) An open valve when the handle is parallel to the pipe

(b) A closed valve when the handle is perpendicular to the pipe

(5) They should be readily accessible.

(6) Valves with removable wrenches should not allow the wrench handle to be installed perpendicularto the fuel gas line when the valve is open.

(7) They should be able to be operated from full open to full close and return without the use of tools.

(A)

Manual shutoff valves should have permanently affixed visual indication of the valve position.

(B)

Quarter-turn valves should not allow the wrench handle to be perpendicular to the fuel gas line whenthe valve is open.

(C)

Wrenches or handles should remain affixed to valves.




Street Address:

City:

State:

Zip:


Committee Statement

Committee Statement: Revised to be consistent with NFPA 86.

Response Message:


Ballot Results


21 Eligible Voters

1 Not Returned


19 of 302 7/7/2014 1:44 PM

19 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


Hudson, James G.

An approved equipment isolation valve....


20 of 302 7/7/2014 1:44 PM



6.2.8 Overpressure Protection.

6.2.8.1

Overpressure protection should be provided in either of the following cases:

(1) When the supply pressure exceeds the pressure rating of any downstream component

(2) When the failure of single upstream line regulator or service pressure regulator results in asupply pressure exceeding the pressure rating of any downstream component

6.2.8.2

Overpressure protection should be provided by any one of the following:

(1) A series regulator in combination with a line regulator or service pressure regulator

(2) A monitoring regulator installed in combination with a line regulator or service pressure regulator

(3) A full-capacity pressure relief valve

(4) An overpressure cutoff device, such as a slam-shut valve or a high pressure switch incombination with an adequately rated shutoff valve

6.2.8.3*

When a relief valve is used to comply with 8.7.1.10 , the relief valve should be a full-capacity relieftype.

6.2.8.4

Token relief valves and internal token relief valves should not be permitted to be used as anoverpressure prevention device.




Street Address:

City:

State:

Zip:


Committee Statement

Committee Statement: Revised to be consistent with NFPA 86.

Response Message:

Ballot Results


21 Eligible Voters

1 Not Returned

19 Affirmative All


21 of 302 7/7/2014 1:44 PM



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


Curry , Dan

Change 6.2.8.4 to "Token relief valves and internal token relief valves shall not be permitted to be used as theonly overpressure prevention device." The existing text would not allow use token relief even when monitoringregulator or other approved OPDs are in place.


22 of 302 7/7/2014 1:44 PM

First Revision No. 8-NFPA 87-2012 [ Sections 6.2.7.7, 6.2.7.8 ]

6.2.7.7

Vent lines from multiple regulators and switches of a single fluid heater, where manifolded together,should be piped in such a manner that diaphragm rupture of one vent line does not backload the others.

6.2.7.7.1

Vents from systems operating at different pressure levels should not be manifolded together.

6.2.7.7.2

Vents from systems served from different pressure reducing stations should not be manifoldedtogether.

6.2.7.7.3

Vents from systems using different fuel sources should not be manifolded together.

6.2.7.8

The size of the vent manifold specified in 6.2.7.7 should be not less than the area of the largest ventline plus 50 percent of the additional vent line area. The cross-sectional area of the manifold lineshould not be less than the greater of the following:

(1) The cross-sectional area of the largest vent plus 50 percent of the sum of the cross-sectionalareas of the additional vent lines

(2) The sum of the cross-sectional areas of the two largest vent lines




Street Address:

City:

State:

Zip:


Committee Statement

CommitteeStatement:

NFPA 87 doesn’t specifically prohibit manifolding vent lines from different pressure sources. It isgood engineering practice not to do this and it is not allowed in NFPA 85. This is something thatshould be addressed in more specifically in NFPA 87. The proposed subparagraphs are extractedfrom NFPA 85 (2011), Section 4.9.3.

ResponseMessage:

Public Input No. 31-NFPA 87-2012 [Sections 6.2.7.7, 6.2.7.8]


Ballot Results


21 Eligible Voters

1 Not Returned

19 Affirmative All



23 of 302 7/7/2014 1:44 PM


0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


Curry, Dan

6.2.7.7.1 What are different pressure levels? At what difference is this enforced? Can we delete because thisconcern is addressed by 6.2.7.7.2?


24 of 302 7/7/2014 1:44 PM





Street Address:

City:

State:

Zip:


Committee Statement


Response Message:


Ballot Results


21 Eligible Voters

1 Not Returned

19 Affirmative All



1 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All

Abstention

Mooney, Mark F.

No language to review.


25 of 302 7/7/2014 1:44 PM


6.3.4.2

The liquid fuel shutoff should be by either of the following:

(1) A remotely located liquid fuel shutoff valve Emergency shutoff valve that meets the followingrequirements:

(a) It should be remotely located away from the fluid heater so that fire or explosion at a fluidheater does not prevent access to this valve.

(b) It should be readily accessible.

(c) It should have permanently affixed visual indication of the valve position.

(d) A removable handle should be permitted provided all the following requirements are satisfied:

i. The valve position is clearly indicated whether the handle is attached or detached.

ii. The valve handle is tethered to the gas main no more than 3 ft (1 m) from the valve ina manner that does not cause personnel safety issues and that allows trouble-freereattachment of the handle and operation of the valve without untethering the handle.

(2) Means for removing power to the positive displacement liquid fuel pump




Street Address:

City:

State:

Zip:


Committee Statement

Committee Statement: Revised for consistency with NFPA 86-2011.

Response Message:


Ballot Results


21 Eligible Voters

1 Not Returned

19 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,


26 of 302 7/7/2014 1:44 PM

Affirmative All


Brown, Amy

It is not clear if you need to comply with one of the subsections or all of them.


27 of 302 7/7/2014 1:44 PM



6.3.4.7

An equipment isolation valve should be provided.




Street Address:

City:

State:

Zip:


Committee Statement


Response Message:


Ballot Results


21 Eligible Voters

1 Not Returned

19 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


Hudson, James G.

An approved equipment isolation valve......


28 of 302 7/7/2014 1:44 PM


6.3.5.3

Liquid fuel piping should be sized to provide flow rates and pressure to maintain a stable flame over theburner operating range.




Street Address:

City:

State:

Zip:


Committee Statement


Response Message:


Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


29 of 302 7/7/2014 1:44 PM



7.2.12*

A confirmed source of combustible gas should be provided to the inlet to the equipment isolationvalve(s) (see 6.2.5.1 ) each time a combustible gas supply is placed into service or restored toservice.




Street Address:

City:

State:

Zip:


Committee Statement

CommitteeStatement:

New Text added for consistency with NFPA 86 (TIA 11-3) and modifications to NFPA 54regarding purging of natural gas lines during commissioning. See FR-64-NFPA 87-2012 forannex material.

ResponseMessage:




Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


30 of 302 7/7/2014 1:44 PM


7.5.15*

Valve seat leakage testing of fuel gas safety shutoff valves should be performed in accordance with themanufacturer's instructions, and testing frequency should be Testing of fuel gas safety shutoff valve seatleakage and valve proving systems should be performed at least annually.




Street Address:

City:

State:

Zip:


Committee Statement

Committee Statement: Same as NFPA 86-2011.

Response Message:


Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


31 of 302 7/7/2014 1:44 PM



7.5.22*

Whenever combustible gas piping is placed into service or removed from service, any release ofcombustible gas should be vented to an approved location.




Street Address:

City:

State:

Zip:


Committee Statement

CommitteeStatement:

Related change to charging and purging of combustible gas systems as requested of NFPA dueto recent accidents. See See FR-65-NFPA 87-2012 for annex to this new section.

ResponseMessage:


Public Input No. 14-NFPA 87-2012 [New Section after A.7.5.17]


Ballot Results


21 Eligible Voters

1 Not Returned

19 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


Mooney , Mark F.

What is an "approved location". Who does the approving? What are the requirements for it being an approvedlocation?


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8.2.1

Thermal The recommendations of Chapter 8 should not apply to thermal liquid heaters with fuel inputratings less than 12,500,000 Btu/hr (3.7 MW) that conform with ASME CSD-1, Controls and SafetyDevices for Automatically Fired Boilers, and or with UL 795, Standard for Commercial-Industrial GasHeating Equipment , meet the recommendations of Chapter 8 .




Street Address:

City:

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Zip:


Committee Statement

CommitteeStatement:

The two documents cover the same scope, therefore conformance with one or the other isappropriate. Also a minor edit to conform to Manual of Style, the two documents meet therecommendations of chapter 8.

ResponseMessage:

Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


33 of 302 7/7/2014 1:44 PM


8.2.8.2

The recommendation in 8.2.8 should not prohibit a time delay applied to the action of a pressure-proving,flow-proving, or proof-of-closure safety switch as used in accordance with 8.7.1.3 (2)(c) , where thefollowing conditions exist:

(1) There is an operational need demonstrated for the time delay.

(2) The use of a time delay is approved.

(3) The time delay feature is not adjustable beyond 5 seconds.

(4) A single time delay does not serve more than one pressure-proving or flow-proving safety device.

(5) The time from an abnormal pressure or flow condition until the holding medium is removed from thesafety shutoff valves does not exceed 5 seconds.




Street Address:

City:

State:

Zip:


Committee Statement

Committee Statement: The Committee deleted 8.7.1.3 in FR-19-NFPA 87-2012.

Response Message:

Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


34 of 302 7/7/2014 1:44 PM



8.2.10

Shutdown of the heating system by any safety feature or safety device should require manualintervention of an operator for re-establishment of normal operation of the system.




Street Address:

City:

State:

Zip:


Committee Statement

Committee Statement: The new paragraph is added to be consistent with NFPA 86.

Response Message:


Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


35 of 302 7/7/2014 1:44 PM



8.2.11

Where transmitters are used in place of switches for safety functions, the following should apply:

(1) The transmitter should possess a safety integrity level (SIL) rating of 2.

(2) Transmitter failure should be detected and initiate a safety shutdown.

(3) The transmitter should be dedicated to safety service unless listed for simultaneous process andsafety service.




Street Address:

City:

State:

Zip:


Committee Statement

CommitteeStatement:

Relocated the transmitter requirement from PLC subsection and makes it generally applicable toall safety controls systems (including hardwired). Also see Public Comment to delete from 8.4.6.

ResponseMessage:


Ballot Results


21 Eligible Voters

1 Not Returned

19 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


Brown , Amy

I'm wondering how onerous providing a SIL2 rating to the combustion system will be particularly with regards to


36 of 302 7/7/2014 1:44 PM

cost. Should it apply to a certain size of system?


37 of 302 7/7/2014 1:44 PM


8.2.9*

A At least one hardwired manual emergency switch should be provided to initiate a safety shutdown.




Street Address:

City:

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Committee Statement

CommitteeStatement:

The 2011 Edition implies there is to be a single manual emergency switch. Depending upon the typeof fluid heater there maybe multiple manual emergency switches to address the multiple “safety”hazards of the fluid heater. All of the fluid heater's safety hazards should be evaluated and a manualemergency “system” should be designed/incorporated into the fluid heater design. The intent of thecommittee is to ensure that at least one emergency shutdown switch is hardwired and operationalwithout use of a PLC or other logic.

ResponseMessage:


Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


38 of 302 7/7/2014 1:44 PM

First Revision No. 49-NFPA 87-2012 [ Sections 8.3, 8.4 ]


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8.3* Logic Systems. Burner Management System Logic.


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8.3.1 General.


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8.3.1.1

Purge, ignition trials, and other burner safety sequencing should be performed using either devices listedfor such service or programmable controllers used in accordance with 8.4 .


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8.3.1.2

The activation of any safety interlock recommended in Chapter 8 should result in a safety shutdown.


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8.3.1.3

Safety interlocks should be in accordance with meet one or more of the following:

(1) Be connected to a combustion safeguard

(2) Hardwired Be hardwired without relays in series ahead of the controlled device

(3) Connected Be connected to an input of a programmable controller logic system complying withSection 8.4

(4) Connected Be connected to a relay that represents a single safety interlock configured to initiatesafety shutdown in the event of power loss

(5) Connected Be connected to a listed safety relay that represents one or more safety interlocksand initiates safety shutdown upon power loss


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8.3.1.4*

Electrical power for safety control circuits should be dc or single-phase ac, 250 volt maximum, one-sidegrounded, with all breaking contacts in the ungrounded, fuse-protected, or circuit breaker–protectedline.

8.3.2 Hardwired Logic Systems.


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8.4* Programmable Logic Controller (PLC) Systems.


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8.4.1

PLC-based Programmable logic controller (PLC)–based systems listed for combustion safety serviceshould be used in accordance with the listing requirements and the manufacturer's instructions.


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8.4.2

PLCs, except those For PLCs that are not listed for combustion safety service, should be used inaccordance with 8.4.2 through 8.4.4 safeguards, the PLC and its associated I/O used to performsafety functions should be certified to IEC 61508 for use in safety applications with a safety integritylevel of 3 or greater .


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8.4.3 General.


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(A)

Before the PLC is placed in operation, documentation should be provided that confirms that allrelated safety devices and safety logic are functional.


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(B)

All changes to hardware or software should be documented and maintained in a file that is separatefrom the fluid heater PLC.


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(C)

System operation should be tested and verified for compliance with the design criteria when thePLC is replaced, repaired, or updated.


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(D)

The control system should have at least one manual emergency switch that initiates a safetyshutdown.


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8.4.3.5

The PLC should detect the following conditions:

(1) Failure to execute any program or task containing safety logic

(2) Failure to communicate with any safety input or output

(3) Changes in software set points of safety functions

(4) Failure of outputs related to safety functions

(5) Failure of timing related to safety functions


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8.4.3.6

A safety shutdown should occur within 3 seconds of detecting any condition listed in 8.4.2.5 .


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8.4.3.7

A dedicated PLC output should initiate a safety shutdown for faults detected by the PLC.


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8.4.3.8

The following devices and logic should be hardwired external to the PLC as follows:

(1) Manual emergency switch

(2) Combustion safeguards

(3) Safe-start checks

(4) Ignition transformers

(5) Trial-for-ignition periods

(6) Excess-temperature controllers

(7) Valve-proving systems


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8.4.3.9

A combustion safeguard should directly control at least one safety shutoff valve between thefuel gas supply and the monitored burner.


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8.4.3.10

Where airflow-proving logic is performed in the PLC, the logic should include the following:

(1) Verification of a change of state in each airflow-proving device during the startup of therelated ventilation equipment

(2) Initiation of a safety shutdown if a change of state in an airflow-proving device is notdetected


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8.4.4 Hardware.


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8.4.4.1

Memory that retains information on loss of system power should be provided for software.


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8.4.4.2

The PLC should have a minimum mean-time-between-failure rating of 250,000 hours.

8.4.4.3

Only one safety device should be connected to a PLC input or output.

8.4.4.4

Output checking should be provided for PLC outputs controlling fuel safety shutoff valves.

8.4.4 Software.

8.4.4.1*

Access to the PLC and its logic should be restricted to authorized personnel. Safety-relatedsoftware should be logically independent from non-safety-related software.

8.4.4.2

Safety-related software should be password-protected or otherwise locked so that access islimited to the fluid heater manufacturer or the burner management system manufacturer.The following power supplies should be monitored:

Power supplies used to power PLC inputs and outputs that control fluid heater safetyfunctions

Power supplies used to power pressure and flow transmitters recommended by8.4.5

8.4.4.3

When any power supply recommended by 8.4.4.2 (1) fails, the dedicated PLC outputrecommended in 8.4.2.7 should be deactivated.

8.4.4.4

When the voltage of any power supply recommended by 8.4.4.2 (2) is detected outsidethe manufacturer's recommended range, the dedicated PLC output recommended in8.4.2.7 8.4.3.7 should be deactivated.

8.4.4.3

Software should be documented as follows:

(1) Labeled to identify elements or groups of elements containing safety software

(2) Labeled to describe the function of each element containing safety software

8.4.4.4

A listing of the programs with documentation should be available.

8.4.5

PLCs that do not comply with 8.4.1 or 8.4.1.1 should comply with the following:

(1) The PLC should not perform required safety functions.

(2) The PLC should not interfere with or prevent the operation of the safetyinterlocks.

(3) Only isolated PLC contacts should be used in the required safety circuits.

8.4.6

Where PLC-based systems use flow transmitters in place of flow switches andpressure transmitters in place of pressure switches for safety functions, the followingshould apply:

(1) The transmitter should be listed, possess a minimum mean-time-between-failurerating of 250,000 hours, or possess a safety integrity level rating of 2.

(2) Upon transmitter failure, the PLC should detect the failure and initiate a safetyshutdown.

(3) The transmitter should be dedicated to safety service unless listed forsimultaneous process and safety service.


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Supplemental Information

File Name Description

FR-49_Legislative_text.docx Showing the section changes in legislative text.

FR-49_Final.docx Showing the final text as the committee intends




Street Address:

City:

State:

Zip:


Committee Statement

CommitteeStatement:

General revisions to sections 8.3 and 8.4 to clarify Committee intent regarding logic systems andthe application of PLC’s.

SIL 3 was chosen because SIL 3 equipment inherently provides the separation and locking of thesafety functions from other functions.

The list of struck items from existing 8.4.2.5 are standard functions of SIL 3 PLCs. Therefore,listing them is redundant. The intent of the committee is to ensure that at least one emergencyshutdown switch is hardwired and operational without use of a PLC or other logic.

ResponseMessage:

Public Input No. 19-NFPA 87-2012 [Section No. 8.3]


Public Input No. 64-NFPA 87-2012 [Sections 8.4.1, 8.4.2]


Ballot Results


21 Eligible Voters

1 Not Returned

15 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


Brown , Amy


63 of 302 7/7/2014 1:44 PM

I'm wondering how onerous providing a SIL2 rating to the combustion system will be particularly with regards tocost. Should it apply to a certain size of system?

Jablkowski, Ted

Will submit PI to 1st revision to revise 8.4.2 to read: "8.4.2 For PLCs that are not listed for combustionsafeguards, the PLC and its associated I/O used to perform safety functions should be certified to IEC 61508 foruse in safety applications with a safety integrity level of 2 or greater and should be applied per the manufacturer’ssafety manual to meet a SIL-2 capable controller." Will submit PI to 1st revision to revise 8.4.4.1 to read: "8.4.4.1*Safety-related software should meet all of the following: (1) The BMS logic, memory, and I/O should beindependent from non-safety logic and memory (2) The BMS logic, memory, and I/O should be protected fromalteration by non-BMS logic or memory access (3) The BMS logic, memory, and I/O should be protected fromalteration by unauthorized users" In 8.4.2, change safety integrity level (SIL) 3 to 2. This is consistant with therequirement proposed in NFPA 86. A SIL 2 capable processor is capable of the secure separation of the BMSsafety logic from the process logic. A SIL 3 capability implies the need for redundancy which has not beendiscussed a new requirement. 8.4.4.1 will be proposed to be changed to the text above in the 2nd revision.Changes are intended to more clearly define the requirements. Annex A.8.4.4.1 may be more appropriate to linkto a hardware requirement.

Martin, Richard J.

This submitter recommended to the NFPA 86 Technical Committee that they should should review this firstrevision (NFPA 87 - FR49) and consider harmonizing their requirements for Section 8.3 (burner managementsystems) and Section 8.4 (programmable logic controllers) with the requirements proposed here. After NFPA 86has prepared its second revision of these sections, the NFPA 87 TC members should reconsider harmonizing theirrequirements to match NFPA 86, (assuming they are revised at the 2nd Draft Meeting).


Dauer, John

Proposed language suggests that PLC's used in combustion service as a flame safeguard and certified toIEC61508 and SIL 2 or greater do not need to meet the listing requirements of flame safeguards. Would prefer itto clearly state that any device used as a flame safeguard shall be approved to be used as a flame safeguard byat least one of the listing agencies. If using a PLC as a flame safeguard, then the PLC and Software need to beapproved, and no modifications can be made to the software without re-approval. This is what is required of flamesafeguard manufacturers whom have devises with internal software for operation.

Tanguay, Francois

I can't find this requirement from NFPA 87-2011 Edition at article 8.4.2.9 A combustion safeguard should directlycontrol at least one safety shutoff valve between the fuel gas supply and the monitored burner. My understandingof that requirement is that even when a PLC is used for combustion service, there is always a certified flamesafeguard in the circuit. But it seems that requirement has been removed??? Which agency will certify that a PLCused in combustion service is certified to IEC61508?


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First Revision No. 17-NFPA 87-2012 [ Section No. 8.5.1.1 [Excluding any Sub-Sections] ]

When a combustion air blower or exhaust blower is provided, a timed pre-ignition purge should beprovided that incorporates all of the following:

(1) At least 4 standard cubic feet (scf) of fresh air or inert gas per cubic foot (4 m 3 /m 3 ) of systemvolume is introduced during the purging cycle.

(2) The system volume includes the heating combustion chambers and all other passages that handlethe recirculation and exhaust of products of combustion to the stack inlet .

(3) All passages from the air inlet to the heater to the stack inlet should be purged.

(4) To begin the timed pre-ignition purge interval, both all of the following conditions are satisfied:

(a) The minimum required pre-ignition purge airflow is proved.

(b) The safety shutoff valve(s) is proved closed. Fluid heaters with total pilot capacity over400,000 Btu/hr should have at least one safety shutoff valve required by 8.7.2.2 proved closedbetween all pilot burners and the fuel supply.

(c) Fluid heaters with total capacity over 400,000 Btu/hr should have at least one safety shutoffvalve proved closed between all main burners and the fuel supply.

(5) The minimum required pre-ignition purge airflow is proved and maintained throughout the timedpre-ignition purge interval.

(6) Failure to maintain the minimum required pre-ignition purge airflow stops the pre-ignition purge andresets the purge timer.




Street Address:

City:

State:

Zip:


Committee Statement

CommitteeStatement:

Possible conflict with 8.7.7.2 if under 400,000 Btu/h. Proved closed is not required when under400,000 Btu/h. The committee also clarified the purge volume requirement.

ResponseMessage:

Public Input No. 73-NFPA 87-2012 [Section No. 8.5.1.1 [Excluding any Sub-Sections]]

Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



65 of 302 7/7/2014 1:44 PM


0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


66 of 302 7/7/2014 1:44 PM

First Revision No. 18-NFPA 87-2012 [ Section No. 8.5.1.1.2 ]

8.5.1.1.2

Repeating the pre-ignition purge on any fuel-fired system can be omitted where any one all of thefollowing conditions is are satisfied:

The heating chamber temperature is proved above 1400°F (760°C).

For any fuel-fired system, all of the following conditions are satisfied:

All of the following conditions are satisfied (does not apply to liquid fuel systems):

Each burner and pilot is supervised by a combustion safeguard in accordance with Section8.9 .

Each burner system is equipped with gas safety shutoff valves in accordance with Section8.7 .

It can be demonstrated that the combustible concentration in the heating chamber and allother passages that handle the recirculation and exhaust of products of combustion cannotexceed 25 percent of the LFL.

(1) Each burner and pilot is supervised by a combustion safeguard in accordance with Section 8.9 .

(2) Each burner system is equipped with safety shutoff valves in accordance with Section 8.7 .

(3) At least one burner remains operating in the common combustion chamber of the burner to bere-ignited.




Street Address:

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Zip:


Committee Statement

CommitteeStatement:

The committee deleted the 1400 deg threshold because it is impractical to maintain in the majorityof fluid heaters. There is no guidance in NFPA 87 that explains what the interlock would becomprised of. Option (3) was deleted because it allowed re-light without purge to occur without anyflame present.

ResponseMessage:

Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



67 of 302 7/7/2014 1:44 PM


0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


68 of 302 7/7/2014 1:44 PM


8.6.5*

Combustion air minimum pressure or flow should be interlocked into combustion safety circuitry . by anyof the following methods:

A low pressure switch that senses and monitors the combustion air source pressure

A differential pressure switch that senses the differential pressure across a fixed orifice in thecombustion air system

An airflow switch




Street Address:

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State:

Zip:


Committee Statement

CommitteeStatement:

There are many methods for proving minimum combustion airflow. The committee believes itshould not be limited to the three previously listed. Additional annex text was added to explainother possible methods.

ResponseMessage:

Ballot Results


21 Eligible Voters

1 Not Returned

19 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


Jablkowski, Ted

Change "combustion safety circuitry" to "Burner Management System". Burner Management System is proposedto be defined in the FR.


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First Revision No. 19-NFPA 87-2012 [ Sections 8.7.1.2, 8.7.1.3 ]

8.7.1.2*

Each safety shutoff valve recommended in 8.7.2.1 and 8.7.3.1 should automatically shut off the fuel tothe burner system after interruption of the holding medium (such as electric current or fluid pressure) byany one of the interlocking safety devices, combustion safeguards, or operating controls . , unlessotherwise permitted by 8.7.1.3 .

8.7.1.3

In fuel gas systems or liquid fuel systems only, where multiple burners or pilots operate as a burnersystem firing into a common heating chamber, the loss of flame signal at one or more burners shouldeither comply with 8.7.1.2 or shut off those burner(s) by closing a single safety shutoff valve, wherethe following conditions are satisfied:

(1) Individual burner safety shutoff valve meets one of the two following conditions:

(a) It is demonstrated, based on available airflow, that failure of the valve to close will resultin a fuel concentration not greater than 25 percent of the LFL.

(b) The safety shutoff valve has proof of closure acceptable to the authority havingjurisdiction.

(2) The safety shutoff valve upstream of the individual burner safety shutoff valves should closewhen any of the following conditions occurs:

(a) Upon activation of any operating control or interlocking safety device other than thecombustion safeguard

(b) Where the individual burner valves do not have proof of closure as described in 8.7.1.3(1)(b) and the number of failed burners is capable of exceeding 25 percent of the LFL ifsingle-burner safety shutoff valves fail in the open position

(c) Where individual burner valves have proof of closure as described in 8.7.1.3 (1)(b) andverification that the individual burner safety shutoff valve has closed following loss of flamesignal at the burner is not present

(d) Upon loss of flame signal at all burners in the burner system or at a number of burners inthe burner system that will result in a fuel concentration greater than 25 percent of the LFL

(e) When the heating chamber is proved at or above 1400°F (760°C) and both of thefollowing conditions exist:

i. Individual burners are shut off by closing a single safety shutoff valve equipped withproof-of-closure switch and proved closed.

ii. If a burner is shut off by closing one safety shutoff valve and that safety shutoffvalve is not proved closed, a second safety shutoff valve upstream closes within 5seconds.




Street Address:

City:

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Zip:



70 of 302 7/7/2014 1:44 PM

Committee Statement

Committee Statement: The Committee believes that two valves should be used on every burner.

Response Message:

Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


71 of 302 7/7/2014 1:44 PM



8.7.1.5

Safety shutoff valves should not be open-close cycled at a rate that exceeds that specified by itsmanufacturer.




Street Address:

City:

State:

Zip:


Committee Statement

Committee Statement: Added section to be consistent with NFPA86-2011.

Response Message:


Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


72 of 302 7/7/2014 1:44 PM

First Revision No. 41-NFPA 87-2012 [ Section No. 8.7.2.2(A) ]

(A)

A proved closed condition should be accomplished by either of the following means:

(1) A proof-of-closure switch incorporated in a listed safety shutoff valve assembly in accordance withthe terms of the listing

(2) A valve-proving system




Street Address:

City:

State:

Zip:


Committee Statement

Committee Statement: Same as NFPA 86-2011.

Response Message:

Public Input No. 68-NFPA 87-2012 [Section No. 8.7.2.2(A)]

Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


73 of 302 7/7/2014 1:44 PM

First Revision No. 50-NFPA 87-2012 [ Section No. 8.9 ]

8.9 Combustion Safeguards (Flame Supervision).

8.9.1

Each burner flame should have a combustion safeguard that has a maximum flame failure response timeof 4 seconds or less , that performs a safe-start check, and that is interlocked into the combustion safetycircuitry in accordance with the following: and that performs a safe-start check.

The flame supervision is not needed in the combustion safety circuitry of a fluid heater when thecombustion chamber temperature is greater than 1400°F (760°C), and the following criteria aremet:

When the combustion chamber temperature drops to less than 1400°F (760°C), the burneris interlocked to allow its operation only if flame supervision has been re-established.

A 1400°F (760°C) bypass controller is used to meet the recommendation in 8.9.1 (1)(a).

Burners without flame supervision are interlocked to prevent their operation when the combustionchamber temperature is less than 1400°F (760°C) by using a 1400°F (760°C) bypass controller.

8.9.2* Flame Supervision.

Each pilot and main burner flame should be equipped with flame supervision in one of the followingways:

(1) Main and pilot flames supervised with independent flame sensors

(2) Main and interrupted pilot flames supervised with a single flame sensor

(3)




Street Address:

City:

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Zip:


Committee Statement

CommitteeStatement:

The committee struck (1) and (2) because 1400 deg F is impractical to maintain in mostfluid heaters.

Response Message:





Ballot Results


21 Eligible Voters

* Self-piloted burner supervised with a single flame sensor


74 of 302 7/7/2014 1:44 PM

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


75 of 302 7/7/2014 1:44 PM



8.10.2.1

The low pressure switch used to supervise the atomizing medium should be permitted to be locatedupstream of atomizing media balancing orifices and balancing valves provided balancing devices areequipped with a locking device to prevent an unintentional change in the setting.




Street Address:

City:

State:

Zip:


Committee Statement

CommitteeStatement:

Taken from a public comment to move A.8.11.2.1 infomration into the mandatory text inNFPA 86-2014.

Response Message:


Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


76 of 302 7/7/2014 1:44 PM



8.15.6

The operating temperature controller and its temperature-sensing element should not be used as theexcess temperature limit interlock.




Street Address:

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Committee Statement

CommitteeStatement:

This is revised to be consistent with coverage for the excess fluid temperature interlock in8.16.9.

Response Message:


Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


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First Revision No. 38-NFPA 87-2012 [ Chapter 9 ]


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9.1* General.


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9.1.1

Class F heaters should be designed for relatively uniform to ensure that the required minimum fluid flowis achieved through parallel all tube passes.


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9.1.1.1*

Equal flow distribution When multiple parallel tube passes are used, balanced flow distribution betweenpasses should be ensured by piping geometry or fixed flow restrictions. , such that each parallel passmaintains the minimum design flow rate, so that maximum fluid film temperatures and maximumallowable material temperatures are not exceeded.


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9.1.1.2

Adjustable balancing trim valves should not be used in multipass Class F heaters.


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9.1.2

The maximum allowable bulk fluid temperature should be determined based on the maximum allowablefluid film temperature that will prevent rapid fluid degradation. and the maximum allowable materialtemperature.


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9.1.3*

The heater manufacturer should determine the minimum flow rate, taking into consideration themaximum allowable bulk fluid temperature and the maximum and film fluid temperature at the designflow rate and all heat input rate rates .


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9.1.4

Where backflow into the heater presents a hazard, a means to prevent backflow should be provided.


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9.1.5

The fluid system should be designed so that fluid cannot installation of a pressure relief valve, ofappropriate pressure and flow rating, should be installed if the fluid can be trapped in the heatedzone.


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9.1.5.1

Discharge from relief valves should be handled in accordance with 9.2.2.


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9.1.5.2

Vent lines should be sized to handle 150 percent of the maximum anticipated flow.


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9.1.6*

The fluid system should be designed to maintain at least the minimum required fluid flow , asdetermined in 9.1.3 , through the heater under all operating conditions.


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9.1.7



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9.1.8

A hard-wired manual emergency switch at a remote location should be provided to initiate a safetyshutdown of the entire fluid heater system at a remote location .


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9.1.9

A means of sampling for fluid contamination or degradation should be provided from the activeloop.


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9.2 Auxiliary Equipment.


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9.2.1 Pumps.


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9.2.1.1*

Air-cooled or water-cooled pumps with mechanical seals or magnetically coupled (seal-less)pumps Pumps that are specifically designed for fluid heater service should be used.


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9.2.1.2*

The pumps should be compatible with the fluid used as well as the operating pressures andtemperatures.


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9.2.1.3

The system should be designed such that there is sufficient net positive suction head availablefor the pump.


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9.2.1.4

Positive displacement pumping systems should incorporate features to ensure that the minimumflow through the heater is maintained. means of pressure relief.


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9.2.1.5*

If water-cooled pumps are used, a means of verifying cooling water flow should be provided.


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9.2.1.6*

Cold alignment of air- and water-cooled pumps should be done in accordance with the pumpmanufacturer’s recommendations prior to the pump being started.


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9.2.1.7*

Hot alignment of air- and water-cooled pumps should be done within the first 24 hours afteroperating temperature has been reached.


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9.2.1.8

Cold and hot alignment should be performed during commissioning and following pumpmaintenance.


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9.2.1.9*

Means should be provided to protect pumps from debris if required for the safe operation ofthe fluid heater.


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9.2.2* Catch Tank. Effluent Handling.

The All effluent from all pressure relief devices, vents from the expansion tank, and drainsfrom the expansion tank should be directed to a closed catch tank. an approved location.


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9.2.2.1


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9.2.2.2

The catch tank should have a vent to atmosphere, with the vent outlet located at anapproved location outside the heater room.


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9.2.2.3

The vent should be adequately sized to handle 150 percent of the maximum flow from theheater relief device.


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9.2.2.4

If the fluid being relieved is combustible, a flame arrester should be located in the ventline.


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9.2.2.5

The contents should not be reused in the fluid heating system.


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9.2.2.6

The catch tank inlets should be located to prevent siphoning of the contents back intothe system.


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9.2.2.7

A liquid level indicator should be provided on the tank.


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9.2.2.1 Gaseous Effluent.


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9.2.2.1.1

Gaseous effluents that are asphyxiants, toxic, or corrosive are outside the scope of thisrecommended practice, and other standards should be consulted for appropriateventing.


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9.2.2.1.2

Flammable gases and oxidizers should be vented to an approved location to preventfire or explosion hazards.


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9.2.2.1.3

When gaseous effluents are vented, the vent pipe should be located in accordancewith the following:

(1) Gaseous effluents should not impinge on equipment, support, building,windows, or materials because the gas could ignite and create a fire hazard.

(2) Gaseous effluents should not impinge on personnel at work in the area or in thevicinity of the exit of the vent pipe because the gas could ignite and create a firehazard.

(3) Gaseous effluents should not be vented in the vicinity of air intakes,compressor inlets, or other devices that utilize ambient air.


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9.2.2.1.4


(1) The pipe exit should not be subject to physical damage or foreign matter thatcould block the exit.

(2) The vent pipe should be sized to minimize the pressure drop associated withlength, fitting, and elbows at the maximum vent flow rate.



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9.2.2.1.5

If the gas is to be vented inside the building, the following additional guidance isoffered:

(1) If the gaseous effluents are flammable and lighter than air, the flammablegases should be vented to a location where the gas is diluted below its LFLbefore coming in contact with sources of ignition.

(2) The gaseous effluents should not re-enter the work area without extremedilution.


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9.2.2.2 Liquid Phase Effluent.


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9.2.2.2.1*

Liquid phase effluent should be directed to a containment vessel where the fluid maybe reused or discarded.


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9.2.2.2.2

The effluent containment vessel should have a vent to atmosphere, with the ventoutlet directed at an approved location.


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9.2.2.2.2.1

If the containment vessel vent has the potential to vent gaseous effluents, therequirements of 9.2.2.1 should apply.


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9.2.2.2.2.2

The vent from the effluent containment vessel should be adequately sized tohandle 150 percent of the maximum anticipated flow.


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9.2.2.2.3

The effluent containment vessel’s inlets should be located to prevent siphoning ofthe contents back into the system.


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9.2.2.2.4

Means for indicating liquid level should be provided on the effluent containmentvessel.


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9.2.2.2.5*

The effluent containment vessel should be designed for the intended service.


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9.2.3 Strainers.


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9.2.3.1

One strainer should be placed in the suction piping of each pump.


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9.2.3.2*

A minimum 60 mesh stainless steel strainer element should be used.


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9.2.3.3

Isolation valves should be placed in the suction and discharge piping of thepump to facilitate cleaning of the strainer.


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9.2.3.4

A means should be provided to drain the strainer prior to cleaning.


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9.2.3.5

A pressure gauge should be placed between the strainer and the pump inlet toindicate strainer blockage.


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9.2.3 Valves.


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9.2.3.1

Gate valves should be used for isolation purposes.


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9.2.3.2

Globe valves or wafer valves should be used for throttling purposes.


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9.2.3.1



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9.2.3.2

Where used, automatic process equipment bypass valves should fail openupon power loss.


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9.2.3.2*

Valves should be selected for the intended application.


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9.2.4.1

The expansion tank should be connected to the fluid system piping upstreamof the fluid pump.


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9.2.4.2*

The expansion tank should be compatible with the fluid being used and thesystem operating temperatures and pressures.


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9.2.4.3*

The expansion tank should be sized to accommodate the fluid expansion inthe entire system.


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9.2.4.4*

A low level switch The expansion tank should be provided equipped with alow-level interlock .


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9.2.4.4.1

The low level switch should be satisfied before the pumps and the heatercan be started.


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9.2.4.4.2

The low level switch should be interlocked to shut down the pump andheater if a low level occurs.


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9.2.4.4.2.1

In situations where maintaining flow is required to protect the heater dueto residual heat, an emergency pump should be used to circulate fluidthrough an emergency cooling system.


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9.2.4.4.3

Indication of low-level interlock activation should be provided.


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9.2.4.5

An Means of draining the expansion tank drain to an approved locationshould be provided.


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9.2.4.6

A means for sampling for water contamination should be provided at thelow point of the expansion tank. An expansion tank vent or an expansiontank pressure relief device should be provided and the effluent should bedirected to an approved location, in accordance to 9.2.2 .


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9.2.4.7

Local or remote indication of tank level should be provided.


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9.2.4.8

Expansion tanks should be vented to the catch tank.


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9.2.4.8*

An expansion tank pressurized with an inert gas should be used if any ofthe following conditions exists exist :


(2) The tank contents can be at a temperature such that exposure ofthe fluid to air would cause degradation of the fluid.



9.2.4.9

All pressurized expansion tanks should be equipped with a pressurerelief device piped to the catch tank.

9.2.4.9*

All expansion tanks that are pressurized over a gauge pressure of 15psi (100 kPa) should meet the requirements of ASME Boiler andPressure Vessel Code , Section VIII Division 1.

9.2.4.10*

Pressurized If pressurization of the expansion tanks tank is requireddue to the vapor pressure of the fluid, the expansion tank should havea blanket gas low inert gas pressure alarm set at a value determinedby the fluid supplier. above the vapor pressure of the fluid at theoperating temperature.

9.2.4.11*

If pressurization of the expansion tank is required due to the netpositive suction head (NPSH) of the pump, the expansion tankshould have a blanket gas low-pressure alarm set to satisfy theNPSH required by the pump.

9.3 Safety Devices for Class F Heaters.


9.3.1.1*

Means One or more interlocks should be provided to prove minimumfluid flow through the heater at all operating conditions.

9.3.1.2

The minimum flow–proving device should be interlocked into thecombustion safety circuitry.

9.3.1.3

Means should be provided to prove minimum fluid level in theexpansion tank at all operating conditions. The minimumflow–proving device should be interlocked to shut down the heater ifa low flow occurs.

9.3.2 Interlocks.

The combustion safety circuitry should incorporate the followinginterlocks:

(1) High stack temperature located upstream of the stack damperHigh flue gas temperature

(2) High process outlet temperature High fluid outlettemperature, measured as close as possible to exit of heatingchamber

(3) Process low flow limit Minimum flow limit


(5) Activation of the heater’s fire suppression system, whereprovided



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FR-38_Chapter_9_FD_Meeting_legislativetext.docx New Chapter 9 with legislative text.




Street Address:

City:

State:

Zip:


Committee Statement

CommitteeStatement:

Chapter 9 is deleted in its entirety to allow insertion of new Chapter 9 (complete), which isprovided in the attachment to this Public Input submission. Chapter 9 has been revised in itsentirety to correlate with newly added Chapter 10.

ResponseMessage:

Public Input No. 7-NFPA 87-2012 [Chapter 9]


Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


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10.1* General. (Reserved)


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10.1.1

Class G heaters should be designed to ensure that the required minimum fluid flow is achievedthrough all tube passes.


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10.1.1.1*

When multiple parallel tube passes are used, balanced flow distribution between passes should beensured, such that each parallel pass maintains the minimum design flow rate, so that maximum fluidfilm temperatures and maximum allowable material temperatures are not exceeded.


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10.1.2

The maximum allowable bulk fluid temperature should be determined based on the maximumallowable fluid film temperature and the maximum allowable material temperature.


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10.1.3*

The heater manufacturer should determine the minimum designed flow rate, taking into considerationthe maximum allowable bulk and film fluid temperature at all flow rates and heat input rates.


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10.1.4

Means of limiting the firing rate in accordance with the actual flow should be provided so thatmaximum fluid film temperature and maximum material temperature is not exceeded.


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10.1.5

Where backflow into the heater presents a hazard, a means to prevent backflow should beprovided.


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10.1.6

The installation of a pressure relief valve, of appropriate pressure and flow rating, should beinstalled if the fluid can be trapped in the heated zone.


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10.1.6.1

Discharge from relief valves should be handled in accordance with 10.2.2 .


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10.1.6.2



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10.1.7*

The fluid system should be designed to maintain at least the minimum required fluid flow (asdetermined in 10.1.3 ) through the heater under all operating conditions.


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10.1.8



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10.1.9

A hard-wired manual emergency switch at a remote location should be provided to initiate asafety shutdown of the entire fluid heater system.


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10.1.10



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10.2.1 Pumps.


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10.2.1.1*

Pumps that are specifically designed for fluid heater service should be used.


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10.2.1.2*



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10.2.1.3



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10.2.1.4

Positive displacement pumping systems should incorporate means of pressure relief.


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10.2.1.5*



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10.2.1.6*



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10.2.1.7*



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10.2.1.8



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10.2.1.9*



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10.2.2* Effluent Handling.

All effluent from relief valves, vents, and drains should be directed to an approved location.


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10.2.2.1.1

Gaseous effluents that are asphyxiants, toxic, or corrosive are outside the scope of thisrecommended practice, and other standards should be consulted for appropriate venting.


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10.2.2.1.2

Flammable gases and oxidizers should be vented to an approved location to prevent fireor explosion hazards.


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10.2.2.1.3

When gaseous effluents are vented, the vent pipe should be located in accordance withthe following:

(1) Gaseous effluents should not impinge on equipment, support, building, windows, ormaterials because the gas could ignite and create a fire hazard.


(3) Gaseous effluents should not be vented in the vicinity of air intakes, compressorinlets, or other devices that utilize ambient air.


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10.2.2.1.4


(1) The pipe exit should not be subject to physical damage or foreign matter that couldblock the exit.




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10.2.2.1.5

If the gas is to be vented inside the building, the following additional guidance is offered:

(1) If the gaseous effluents are flammable and lighter than air, the flammable gasesshould be vented to a location where the gas is diluted below its LFL beforecoming in contact with sources of ignition.



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10.2.2.2.1*

Liquid phase effluent should be directed to a containment vessel where the fluid can bereused or discarded.


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10.2.2.2.2

The effluent containment vessel should have a vent to atmosphere, with the vent outletdirected at an approved location.


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10.2.2.2.2.1



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10.2.2.2.2.2

The vent from the effluent containment vessel should be adequately sized to handle150 percent of the maximum anticipated flow.


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10.2.2.2.3

The effluent containment vessels inlets should be located to prevent siphoning of thecontents back into the system.


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10.2.2.2.4



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10.2.2.2.5*



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10.2.3 Valves.


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10.2.3.1



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10.2.3.2*



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10.2.4.1

The expansion tank should be connected to the fluid system piping upstream ofthe fluid pump.


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10.2.4.2*



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10.2.4.3*



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10.2.4.4*

The expansion tank should be equipped with a low-level interlock.


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10.2.4.4.1

The low-level interlock should be satisfied before the pumps and the heater canbe started.


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10.2.4.4.2

The low-level interlock should shut down the pump and heater if a low leveloccurs.


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10.2.4.4.2.1

In situations where maintaining flow is required to protect the heater due toresidual heat, an emergency pump should be used to circulate fluid through anemergency cooling system.


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10.2.4.4.3



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10.2.4.5

Means of draining the expansion tank to an approved location should beprovided.


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10.2.4.6

An expansion tank vent or an expansion tank pressure relief device should beprovided and the effluent should be directed to an approved location, inaccordance with 10.2.2 .

10.2.4.7

Local or remote indication of expansion tank level should be provided.

10.2.4.8*

An expansion tank pressurized with an inert gas should be used if any of thefollowing conditions exist:


(2) The tank contents can be at a temperature such that exposure of thefluid to air would cause degradation of the fluid.

(3) The fluid manufacturer requires use of an inert blanket.

(4) The fluid is operated at or above its atmospheric boiling point.

10.2.4.9*

All expansion tanks that are pressurized over a gauge pressure of 15 psi(100 kPa) should meet the requirements of ASME Boiler and PressureVessel Code , Section VIII Division 1.

10.2.4.10*

If pressurization of the expansion tank is required due to the vapor pressureof the fluid, the expansion tank should have a blanket gas low-pressurealarm set at a value above the vapor pressure of the fluid at the operatingtemperature.

10.2.4.11*

If pressurization of the expansion tank is required due to the net positivesuction head (NPSH) of the pump, the expansion tank should have ablanket gas low-pressure alarm set to satisfy the NPSH required by thepump.

10.3 Safety Devices for Class G Heaters. (Reserved)


10.3.1.1*

One or more interlocks should be provided to prove minimum fluid flowthrough the heater at all operating conditions.

10.3.1.2


10.3.1.3

The minimum flow-proving device should be interlocked to shut down theheater if a low flow occurs.

10.3.2 Interlocks.



(2) High fluid outlet temperature, measured as close as possible to exitof heating chamber



(5) Activation of the heater’s fire suppression system, where provided



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Chapter10_FD_Meeting.docx Chapter 10 rewrite with amendments from FD Meeting




Street Address:

City:

State:

Zip:


Committee Statement

CommitteeStatement:

New required and annex text for Class G fluid heaters, generated to replace reserved space.FR-60-NFPA 87-2012, contains the new annex for this chapter.

ResponseMessage:


Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


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11.1* General. (Reserved)


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11.1.1

Class H heaters should be designed to ensure that the required minimum fluid flow is achievedthrough all flow paths.


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11.1.1.1*

When multiple parallel flow paths are used, balanced flow distribution between flow paths should beensured, such that each parallel path maintains the minimum design flow rate, so that maximum fluidfilm temperatures and maximum allowable material temperatures are not exceeded.


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11.1.2

The maximum allowable bulk fluid temperature should be determined based on the maximumallowable fluid film temperature and the maximum allowable material temperature.


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11.1.3*

The heater manufacturer should determine the minimum designed flow rate, taking into considerationthe maximum allowable bulk and film fluid temperature at the design flow rate and all heat inputrates.


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11.1.4

The temperature of all heat transfer surfaces in contact with the fluid should be below thetemperature at which fluid degradation can occur under all operating conditions.


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11.1.5

Where backflow into the heater presents a hazard, a means to prevent backflow should beprovided.


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11.1.6

The installation of a pressure relief valve, of appropriate pressure and flow rating, should beinstalled if the fluid can be trapped in the heated zone.


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11.1.6.1

Discharge from relief valves should be handled in accordance with 11.2.2 .


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11.1.6.2



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11.1.7*

The fluid system should be designed to maintain at least the minimum required fluid flow (asdetermined in 11.1.3 ) through the heater under all operating conditions.


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11.1.8



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11.1.9

A hard-wired manual emergency switch at a remote location should be provided to initiate asafety shutdown of the entire fluid heater system.


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11.1.10



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11.2.1 Pumps.


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11.2.1.1*

Pumps that are specifically designed for fluid heater service should be used.


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11.2.1.2*



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11.2.1.3



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11.2.1.4

Positive displacement pumping systems should incorporate means of pressure relief.


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11.2.1.5*



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11.2.1.6*



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11.2.1.7



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11.2.1.8



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11.2.1.9*



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11.2.2* Effluent Handling.

All effluent from relief valves, vents, and drains should be directed to an approved location.


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11.2.2.1.1

Gaseous effluents that are asphyxiants, toxic, or corrosive are outside the scope of thisrecommended practice, and other standards should be consulted for appropriate venting.


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11.2.2.1.2

Flammable gases and oxidizers should be vented to an approved location to prevent fireor explosion hazards.


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11.2.2.1.3

When gaseous effluents are vented, the vent pipe should be located in accordance withthe following:

(1) Gaseous effluents should not impinge on equipment, support, building, windows, ormaterials because the gas could ignite and create a fire hazard.


(3) Gaseous effluents should not be vented in the vicinity of air intakes, compressorinlets, or other devices that utilize ambient air.


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11.2.2.1.4


(1) The pipe exit should not be subject to physical damage or foreign matter that couldblock the exit.




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11.2.2.1.5

If the gas is to be vented inside the building, the following additional guidance is offered:

(1) If the gaseous effluents are flammable and lighter than air, the flammable gasesshould be vented to a location where the gas is diluted below its LFL beforecoming in contact with sources of ignition.



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11.2.2.2.1*

Liquid phase effluent should be directed to a containment vessel where the fluid can bereused or discarded.


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11.2.2.2.2

The effluent containment vessel should have a vent to atmosphere, with the vent outletdirected at an approved location.


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11.2.2.2.2.1



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11.2.2.2.2.2

The vent from the effluent containment vessel should be adequately sized to handle150 percent of the maximum anticipated flow.


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11.2.2.2.3

The effluent containment vessel's inlets should be located to prevent siphoning of thecontents back into the system.


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11.2.2.2.4



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11.2.2.2.5*



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11.2.3 Valves.


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11.2.3.1



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11.2.3.2*



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11.2.4.1

The expansion tank should be connected to the fluid system piping upstream ofthe fluid pump.


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11.2.4.2*



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11.2.4.3*



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11.2.4.4*

The expansion tank should be equipped with a low-level interlock.


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11.2.4.4.1

The low-level interlock should be satisfied before the pumps and the heater canbe started.


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11.2.4.4.2

The low-level interlock should shut down the pump and heater if a low leveloccurs.


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11.2.4.4.2.1

In situations where maintaining flow is required to protect the heater due toresidual heat, an emergency pump should be used to circulate fluid through anemergency cooling system.


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11.2.4.4.3



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11.2.4.5

Means of draining the expansion tank to an approved location should beprovided.


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11.2.4.6

An expansion tank vent or an expansion tank pressure relief device should beprovided and the effluent should be directed to an approved location, inaccordance with 11.2.2 .

11.2.4.7

Local or remote indication of expansion tank level should be provided.

11.2.4.8*

An expansion tank pressurized with an inert gas should be used if any of thefollowing conditions exist:


(2) The tank contents can be at a temperature such that exposure of thefluid to air would cause degradation of the fluid.

(3) The fluid manufacturer requires use of an inert blanket.

(4) The fluid is operated at or above its atmospheric boiling point.

11.2.4.9*

All expansion tanks that are pressurized over a gauge pressure of 15 psi(100 kPa) should meet the requirements of ASME Boiler and PressureVessel Code , Section VIII Division 1.

11.2.4.10*

If pressurization of the expansion tank is required due to the vapor pressureof the fluid, the expansion tank should have a blanket gas low-pressurealarm set at a value above the vapor pressure of the fluid at the operatingtemperature.

11.2.4.11*

If pressurization of the expansion tank is required due to the net positivesuction head (NPSH) of the pump, the expansion tank should have ablanket gas low-pressure alarm set to satisfy the NPSH required by thepump.

11.3 Safety Devices for Class H Heaters. (Reserved)


11.3.1.1*

One or more interlocks should be provided to prove minimum fluid flowthrough the heater at all operating conditions.

11.3.1.2


11.3.1.3

The minimum flow-proving device should be interlocked to shut down theheater if a low flow occurs.

11.3.2 Interlocks.



(2) High fluid outlet temperature, measured as close as possible to exitof heating chamber



(5) Activation of the heater’s fire suppression system, where provided



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Chapter11_FD_Meeting.docx Chapter 11 rewrite with amendments from FD Meeting




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Committee Statement

CommitteeStatement:

The NFPA 87 Technical Committee wishes to compile a "complete" version of the RecommendedPractice during the current cycle so that the public can review and get to know the RP over the nextfour years, and provide input to the committee on all three types of fluid heaters (Class F, G, and H)before the following edition is put up for consideration as a Standard (instead of an RP). SeeFR-61-NFPA 87-2012 for the added annex material.

ResponseMessage:


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Hudson, James G.

Quiescent bath type heaters are not covered by the recommended practice.


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First Revision No. 63-NFPA 87-2013 [ New Section after A.3.2.4 ]


A.3.3.17 Hardwired.

When the term hardwired is applied to the logic system itself, it refers to the method of using individualdevices and interconnecting wiring to program and perform the logic functions without the use ofsoftware-based logic solvers.




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Submittal Date: Mon Jan 07 09:44:19 EST 2013

Committee Statement

Committee Statement: Annex material for FR-44-NFPA 87-2012, the term hardwired.

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First Revision No. 53-NFPA 87-2012 [ Section No. A.5.3 ]

A.5.3

For additional information regarding explosion protection of equipment and buildings, see NFPA 68 ,Standard on Explosion Protection by Deflagration Venting , and NFPA 69 , Standard on ExplosionPrevention Systems .

Where explosion relief is provided, its location is a critical concern and should be close to the ignitionsource. Personnel considerations and proximity to other obstructions can affect the location selected forthese vents. The intent of providing explosion relief in furnaces is to limit damage to the furnace and toreduce the risk of personnel injury due to explosions. To achieve those goals, relief panels and doorsshould be sized so that their inertia does not preclude their ability to relieve internal explosion pressures.

Damage-limiting construction could include exterior panels that are designed to become detached underthe influence of internal pressure from a deflagration. In such cases, tethering the panels is vitallyimportant to ensure dislodged panels don't cause injury or damage. NFPA 68 provides guidance fortethering doors and walls that can become dislodged in a deflagration event.




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Submittal Date: Wed Nov 28 23:12:01 EST 2012

Committee Statement

CommitteeStatement:

Fluid heaters are generally not designed to withstand internal pressures developed by adeflagration. As such, containment and explosion suppression are likely not viable options. Locationis not an ideal solution, because it is impossible to ensure personnel will never be working in thearea of an operating fluid heater especially during start-up and shutdown. By combining tethers witha -damage limiting construction" approach, the traditional design features of many fluid heaters canbe made safer.

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Public Input No. 17-NFPA 87-2012 [New Section after A.5.3]

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Wechsler, Tom ,

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270 of 302 7/7/2014 1:44 PM

First Revision No. 12-NFPA 87-2012 [ Section No. A.5.5.1.3 ]

A.5.5.1.3

Threaded connections in the flow circuit typically are not used on piping greater than 1 in. (25 mm) NPT.Flanged and threaded connections are not recommended for flammable or combustible liquids due topossible leakage. Additional guidance can be found in ASME B31.3, Process Piping .




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CommitteeStatement:

This explanatory input and the new text (5.5.1.3 and subsections) clarifies the committee'sintent that welded connections should be used as often as is practical.

ResponseMessage:

Public Input No. 5-NFPA 87-2012 [Section No. A.5.5.1.3]

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First Revision No. 55-NFPA 87-2012 [ New Section after A.6.2.7.5 ]

A.6.2.7.9

NFPA 87 does not address vents between safety shutoff valves, but they are sometimes installed.

A.6.2.8.3

Token relief valves only provide minimum pressure relief in cases where ambient temperaturesincrease the pressure inside the gas piping, which can occur during shutdown periods, or relieves asmall increase of pressure due to high lockup pressures that occur during a shutdown.




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Annex material added to clarify new section added by FR-31-NFPA 87-2012 andFR-36-NFPA 87-2012.

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A.7.2.12

The evacuation/purging, charging, and confirmation of the fuel or combustible gas supply in the pipingupstream of the equipment isolation valve is goverend by other codes, standards, and recommendedpractices. Examples are NFPA 54 , National Fuel Gas Code , which requires charging to be stoppedupon detection of combustible gas at the point of discharge, and NFPA 56PS , Standard for Fire andExplosion Prevention During Cleaning and Purging of Flammable Gas Piping Systems . Carefulconsideration should be given to the potential hazards that can be created in the surrounding area forany fuel or combustible gas discharge.

In NFPA 54 , the term Appliance Shutoff Valve is analogous to the term Equipment Isolation Valve inNFPA 86 and 87.




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Committee Statement: Annex material for FR-10-NFPA 87-2012.

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A.7.5.22

See A.6.2.7.3 .




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Committee Statement: Annex material for FR-13-NFPA 87-2012.

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274 of 302 7/7/2014 1:44 PM

First Revision No. 15-NFPA 87-2012 [ Section No. A.8.2.9 ]

A.8.2.9

For some applications, additional manual action might be required to bring the process to a safecondition. The actions resulting from a manual emergency switch action take into account the individualsystem design and the hazards (e.g., mechanical, combustion system, process fluid, thermal fluid, etc.)associated with changing the existing state to another state and initiates actions to cause the system torevert to a safe condition.




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Committee Statement: Annex text was added to further clarify the document text.

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Public Input No. 36-NFPA 87-2012 [Section No. A.8.2.9]

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First Revision No. 46-NFPA 87-2012 [ Section No. A.8.3 ]

A.8.3

Furnace controls Fluid heater controls that meet the performance-based requirements of standards suchas ANSI/ISA 84.00.01, Application of Safety Instrumented Systems for the Process Industries , or IEC61511, Functional Safety: Safety Instruments Systems for the Process Industry Sector , can beconsidered equivalent. The determination of equivalency involves complete conformance to the safety lifecycle, including risk analysis, safety integrity level selection, and safety integrity level verification, whichshould be submitted to the authority having jurisdiction.




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Committee Statement: IEC61511 is exactly equivalent to ANSI/ISA84.00.01.

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Public Input No. 27-NFPA 87-2012 [Section No. A.8.3]

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A.8.3.1.4

This control circuit and its non-furnace-mounted or furnace-mounted control and safety componentsshould be housed in a dusttight panel or cabinet, protected by partitions or secondary barriers, orseparated by sufficient spacing from electrical controls employed in the higher voltage furnace powersystem. Related instruments might or might not be installed in the same control cabinet. The doorproviding access to this control enclosure might include means for mechanical interlock with the maindisconnect device required in the furnace power supply circuit.

Temperatures within this control enclosure should be limited to 125°F (52°C) for suitable operation ofplastic components, thermal elements, fuses, and various mechanisms that are employed in the controlcircuit.




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Committee Statement: Section renumbered in FR-49-NFPA 87-2012.

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Could not find A.8.3.2.2 in the on-line revision.


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First Revision No. 58-NFPA 87-2012 [ New Section after A.8.4 ]


A.8.4.4.1

This recommended practice suggests that the signal from the safety device be directly transmitted tothe safety PLC input. Once the safety PLC processes the signal the resulting data can be used for anypurpose.




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Submittal Date: Thu Nov 29 15:12:16 EST 2012

Committee Statement

Committee Statement: Annex material added from FR-49-NFPA 87-2012.

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First Revision No. 26-NFPA 87-2012 [ New Section after A.8.5.1.2(1) ]


A.8.5.1.2.1(2)

Consideration should be given to the proximity of operating burners when the common combustionchamber exception to repeating purges is utilized. Accumulation of localized vapors or atmospheres ispossible even with an operating burner in a chamber, depending on the size of the chamber, thenumber of burners, and the proximity of operating burners to the accumulation. In addition to proximity,burner design and exposure of the flame can also impact the ability of the operating burner to mitigatevapor or gaseous accumulations.




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Committee Statement

Committee Statement: Annex material is added to be consistent with NFPA 86-2011.

Response Message:

Public Input No. 40-NFPA 87-2012 [New Section after A.8.5.1.2(1)]

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279 of 302 7/7/2014 1:44 PM


A.8.6.5

Interlocks for combustion air minimum pressure or flow can be provided by any of the following methods:

(1) A low-pressure switch that senses and monitors the combustion air source pressure. In industrialcombustion applications with modulating flow control valves downstream of the combustion airblower, it is most common to interlock the constant combustion air source pressure on single-burner and multiburner systems to meet the recommendations of 8.6.3 and 8.6.5 . Because thecombustion airflow is proved during each purge cycle along with the combustion air sourcepressure, the most common convention is to prove the combustion air source pressure duringburner operation following purge. In a multiburner system, the proof of combustion airflow duringpurge proves that any manual valves in the combustion air system are in an adequately openposition. These manual air valves are provided for maintenance and combustion airflow balancingamong burners in a temperature control zone. In combustion air supply systems that use either aninlet damper or a speed control, the combustion air pressure can fall below reliably repeatablelevels with listed pressure switch interlocks at low fire. For these systems, the proof of minimumairflow can be a more reliable interlock.

(2) A differential pressure switch that senses the differential pressure across a fixed orifice in thecombustion air system. In combustion air supply systems that use either an inlet damper or aspeed control, the combustion air pressure can fall below reliably repeatable levels with listedpressure switch interlocks at low fire. For these systems, the proof of minimum airflow by use of adifferential pressure switch across an orifice can be a more reliable interlock.

(3) An airflow switch. In combustion air supply systems that use either an inlet damper or a speedcontrol, the combustion air pressure can fall below reliably repeatable levels with listed pressureswitch interlocks at low fire. For these systems, the proof of minimum airflow by use of an airflowswitch can be a more reliable interlock.

(4) A pressure switch on the inlet (suction) side of an induced draft (I.D.) fan. For heaters whereairflow is induced by an I.D. fan, a pressure switch on the inlet of the I.D. fan can be used to provethat the minimum required suction pressure is available, which along with proof that air and stackdampers are not closed can be used as a minimum air flow interlock.

(5) For combustion systems that use high pressure gas/air to induce (inspirate) air locally at eachburner or that use natural draft to induce air into the burners or combustion champer, proof that airand stack dampers are not closed/open to at least a minimum position can be used to satisfy theintent of a low air flow interlock. It is not possible to monitor and prove the availability ofcombustion air for fluid heaters that use natural draft or air inspiriting burners.




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Committee Statement: The revision explains several methods for proving the minimum combustion airflow.

Response Message:


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Public Input No. 45-NFPA 87-2012 [Section No. A.8.6.5]

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A.8.7.1.3

Paragraph 8.7.1.3 addresses conditions under which only one safety shutoff valve is to close toisolate a burner from its fuel gas supply. Figure A.8.7.1.3 provides a summary of 8.7.1.3 in the formof a decision tree. See 8.5.1.1.2 for guidance regarding conditions that are needed to allow thatburner to be placed back in service. The requirements of 8.5.1.1.2 might not allow a burner shut off byclosing a single safety shutoff valve to be placed back in service without repeating a pre-ignition purge.

The requirements of 8.7.1.3 do not preclude opening of the safety shutoff valve located upstream ofthe individual burners using single safety shutoff valves during the trial for ignition for the first burnerbeing lighted.

Figure A.8.7.1.3 Safety Shutoff Decision Tree




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Response Message:

Public Input No. 66-NFPA 87-2012 [New Section after A.8.7.1.2]

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A.8.9.2

Ultraviolet detectors can fail in such a manner that the loss of flame is not detected. When these detectorsare placed in continuous service, failures can be detected by use of a self-checking ultraviolet detector orby periodic testing of the detector for proper operation.

Flame detectors (scanners) with combustion safeguards that continuously operate beyond the maximuminterval recommended by the combustion safeguard and flame detector manufacturer's instructionswould not be compliant.




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Committee Statement: The statement is added to reinforce compliance with manufacturer's instructions.

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Public Input No. 84-NFPA 87-2012 [New Section after A.8.7.3.3]

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First Revision No. 67-NFPA 87-2013 [ New Section after A.9.1 ]

A.9.1.1.1

Balanced flow is typically achieved by the piping geometry or fixed flow restrictions. If fluid flow ratesfall below the designed minimum flow rate, fluid overheating and subsequent degradation can occur.Some heater designs have one flow rate for tubes in the radiant section and another flow rate for tubesin the convective section.

If balancing trim valves are used, the flow through each pass should be monitored and interlocked intothe combustion safety circuitry. Manual balancing trim valves should also have provisions to lock thevalve to prevent inadvertent adjustment of the valve.

A.9.1.3

The maximum bulk fluid temperature is typically measured at the outlet of the heater.




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Committee Statement: Added annex material to reflect new changes in Chapter 9, from FR-38-NFPA 87-2012.

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A.9.1.5

The installation of a pressure relief valve between the blocking valves or of a block valve at the inlet tothe heater and a check valve at the outlet can be used.




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A.9.2.1.1

Air-cooled or water-cooled pumps with mechanical seals, canned motor pumps, seal-less pumps, andpumps that are magnetically coupled are examples of pumps that are used. If magnetically coupledpumps are used, over-temperature protection of the pump coupling location should be provided.Packing-based seals are prone to leakage and are not recommended. The pump material selectionshould take into account the possible thermal shock experienced under fire suppression scenarios.




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A.9.2.1.2

The fluid manufacturer and the heater manufacturer the person or company responsible for the design orsupply of the fluid heater should be consulted to provide recommendations on the appropriate pump forthe application.




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A.9.2.2

If the fluid being relieved is combustible, measures should be taken to prevent ignition of the vapors oraerosols from the vent. Additional guidance can be found in NFPA 30 , Flammable and CombustibleLiquids Code .

A.9.2.2.2.1

Containment vessels for liquids include drain tanks, fill tanks, supplemental storage tanks, and catchtanks.




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289 of 302 7/7/2014 1:44 PM

First Revision No. 72-NFPA 87-2013 [ Sections A.9.2.3.2, A.9.2.4.3 ]

A.9.2.3.2

Refer to the pump manufacturer’s manual for additional instructions.

A.9.2.4.3

Cast steel or ductile iron valves with steel or stainless steel trim are typically used.

A.9.2.2.2.5

Secondary containment of effluent containment vessel should be considered if the fluid is flammableor hazardous.

A.9.2.3.2

Gate and ball valves can be used for isolation purposes, and globe or wafer-style butterfly valvescan be used for throttling purposes.




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A.9.2.4.2

Expansion tanks are typically fabricated from carbon and stainless steel.




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291 of 302 7/7/2014 1:44 PM

First Revision No. 74-NFPA 87-2013 [ Section No. A.9.2.5.3, A.9.2.4.4 ]

A.9.2.4.3

Expansion tanks are typically 2.5 times the expansion volume of the system. The operating temperature,the expansion coefficient of the fluid, and the system volume are used to calculate this value the volumeof the expansion tank . Some vapor space should remain in the tank when the system is at operatingtemperature. If the tank is located outdoors, an inert blanket should be considered to minimize moistureingress into the system. For very large systems, where expansion tanks are elevated and workingvolume exceeds 1000 gallons, a secondary, ground-level catch/storage tank and refill pumps can beused to take up excess expansion volume.

A.9.2.4.4

In addition to the low-level interlock, on large volume systems, it is good practice to use dynamic leakdetection (rate of change monitoring) on expansion tanks. Dynamic leak detection is encouragedbecause it will detect abnormal fluid loss over time whereas a low-level switch is a single set point andoften located just above tank empty. In some situations, expansion tanks can be several thousandgallons in capacity. Therefore, if only low-level monitoring is provided, several thousand gallons couldescape the system before the alarm is sounded. With dynamic leak detection, alarm notification of thefalling oil level will be made much sooner.




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292 of 302 7/7/2014 1:44 PM

First Revision No. 75-NFPA 87-2013 [ Section No. A.9.2.5.9, A.9.2.4.9, A.9.2.4.10,

A.9.2.4.11 ]

A.9.2.4.8

Nitrogen is typically used as the inert blanket. Other gases, such as carbon dioxide, can be used. In theoil and gas industry it is common to use flammable gases. If using flammable gases, other precautionsshould be considered, such as area classification and explosion-proof electrical devices.

A.9.2.4.9

Consideration should be given to pressure surges that can occur during process upsets that canexpose the expansion tank to pressures greater than 15 psi. An example of a common process upsetis the rapid pressure rise due to water flashing to steam. For this reason, many users specifyexpansion tanks to meet the requirements of ASME Boiler and Pressure Vessel Code , Section VIIIDivision 1.

A.9.2.4.10

A blanket gas low-pressure interlock should be considered where low blanket gas pressure couldcreate a fluid heater system hazard.

A.9.2.4.11

See A.9.2.4.10 .




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1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


293 of 302 7/7/2014 1:44 PM


A.9.3.1.1

The required minimum fluid flow rate is based on design requirements. Detecting only flow/no flowconditions might be inadequate is not adequate . A pressure switch at the pump discharge , and apump rotation switch, and a flow paddle switch are examples of proving devices that are notrecommended to prove minimum flow as unexpected blockages in the heater tubes will not be detectedby these devices . For example, restriction of flow will result in an increase in the fluid outlet temperature,which in turn will drive a reduction in heat input (low fire). Low flow rates under this condition could causelaminar flow in the tubes, resulting in undetected localized fluid skin overtemperature conditions. Using avortex-shedding meter or similar flow measurement device can provide reliable minimum flow verification.However, a failure modes and effects analysis should be conducted to ensure that the implementation issufficiently reliable for a safety function implementation. Another option is to use a combination ofpressure differential measurements across a known restriction combined with low and high pressurelimits. The high pressure limits will detect blockage or other abnormal flow restrictions that maintain highdifferential pressures at low flow conditions. Conversely, low pressure limits can detect system leaks orbypass flows.

Orifice plate(s) located at the outlet of a fluid heater and used with differential pressure interlock(s) are areliable way of proving the minimum flow. If pressure drop across the heater is used, additional interlocksand precautions should be considered.




Street Address:

City:

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Zip:


Committee Statement


Response Message:

Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


294 of 302 7/7/2014 1:44 PM

First Revision No. 60-NFPA 87-2012 [ Section No. A.10.1, A.10.1.1.1, A.10.1.3, A.10.1.7,

A.10.2.1.1, A.10.2.1.2, A.10.2.1.5, A.10.2.1.6, A.10.2.1.7, A.10.2.1.9, A.10.2.2, A.10.2.2.2.1,A.10.2.2.2.5, A.10.2.3.2, A.10.2.4.2, A.10.2.4.3, A.10.2.4.4, A.10.2.4.8, A.10.2.4.9, A.10.2.4.10,A.10.2.4.11, A.10.3.1.1 ]

A.10.1

Class G heaters have fluid inside the tubes with modulated fluid flow rate (e.g., by process demand) andwhere the outlet temperature of the fluid is controlled by modulation of the heat input rate to the outside ofthe tubes.

Class G fluid heaters present the following two major hazards:

(1) Uncontrolled release of the fluid, which can cause tube cracking or rupture, pump seal failure, fire,or explosion which can result in fire or explosion

(2) Combustible accumulation and explosion Release and accumulation of combustible fuel gas orliquid, followed by ignition and explosion

A.10.1.1.1

Balanced flow is typically achieved by the piping geometry or fixed flow restrictions. If fluid flow ratesfall below the designed minimum flow rate, fluid overheating and subsequent degradation can occur.Some heater designs have one flow rate for tubes in the radiant section and another flow rate fortubes in the convective section.


A.10.1.3


A.10.1.7

The fluid flow control device should have mechanical stops or equivalent provisions to prevent theflow from dropping below the minimum design flow. Variable speed pumping systems should providea minimum motor speed limit to prevent flow less than the minimum required level in both automaticand manual operation.

A.10.2.1.1

Air-cooled or water-cooled pumps with mechanical seals, canned motor pumps, seal-less pumps,and pumps that are magnetically coupled are examples of pumps that are used. If magneticallycoupled pumps are used, over-temperature protection of the pump coupling location should beprovided. Packing-based seals are prone to leakage and are not recommended. The pump materialselection should take into account the possible thermal shock experienced under fire suppressionscenarios.

A.10.2.1.2

The fluid manufacturer and the heater manufacturer should be consulted to providerecommendations on the appropriate pump for the application.

A.10.2.1.5

Loss of cooling can cause seal failure and a subsequent fire hazard.

A.10.2.1.6

Misalignment can cause seal failure and a subsequent fire hazard.

A.10.2.1.7

The alignment of the pump can change during the transition from cold to operatingtemperatures.

A.10.2.1.9

Examples of devices to protect pumps can be drip legs, strainers, filters, and screens.


295 of 302 7/7/2014 1:44 PM

A.10.2.2

If the fluid being relieved is combustible, measures should be taken to prevent ignition of thevapors or aerosols from the vent. Additional guidance can be found in NFPA 30 , Flammableand Combustible Liquids Code .

A.10.2.2.2.1

Containment vessels for liquids include drain tanks, fill tanks, supplemental storage tanks,and catch tanks.

A.10.2.2.2.5

Secondary containment of effluent containment vessel should be considered if the fluid isflammable or hazardous.

A.10.2.3.2

Gate and ball valves can be used for isolation purposes, and globe or wafer-style butterflyvalves can be used for throttling purposes.

A.10.2.4.2


A.10.2.4.3

The operating temperature, the expansion coefficient of the fluid, and the system volumeare used to calculate the volume of the expansion tank. Some vapor space should remainin the tank when the system is at operating temperature. If the tank operates atatmospheric pressure and is located outdoors, an inert gas blanket should be consideredto minimize moisture ingress into the system. For very large systems, where expansiontanks are elevated and working volume exceeds 1000 gallons, a secondary, ground-levelcatch/storage tank and refill pumps can be used to take up excess expansion volume.

A.10.2.4.4

In addition to the low-level interlock, on large-volume systems, it is good practice to usedynamic leak detection (rate of change monitoring) on expansion tanks. Dynamic leakdetection is encouraged because it will detect abnormal fluid loss over time whereas alow-level switch is a single set point and often located just above tank empty. In somesituations, expansion tanks can be several thousand gallons in capacity. Therefore, ifonly low-level monitoring is provided, several thousand gallons could escape the systembefore the alarm is sounded. With dynamic leak detection, alarm notification of the fallingoil level will be made much sooner.

A.10.2.4.8

Nitrogen is typically used as the inert blanket. Other gases, such as carbon dioxide, canbe used. In the oil and gas industry it is common to use flammable gases. If usingflammable gases, other precautions can be required, such as area classification andexplosion-proof electrical devices.

A.10.2.4.9

Consideration should be given to pressure surges that can occur during processupsets that can expose the expansion tank to pressures greater than 15 psi. Anexample of a common process upset is the rapid pressure rise due to water flashing tosteam. For this reason, many users specify expansion tanks that meet therequirements of ASME Boiler and Pressure Vessel Code , Section VIII Division 1.

A.10.2.4.10

A blanket gas low-pressure interlock should be considered where low blanket gaspressure can create a fluid heater system hazard.

A.10.2.4.11

See A.10.2.4.10 .


296 of 302 7/7/2014 1:44 PM

A.10.3.1.1

Detecting only flow/no flow conditions is not adequate. A pressure switch at thepump discharge and a pump rotation switch are examples of proving devices thatare not recommended to prove minimum flow as unexpected blockages in theheater tubes will not be detected by these devices.

Orifice plate(s) located at the outlet of a fluid heater and used with differentialpressure interlock(s) are a reliable way of proving the minimum flow. If pressuredrop across the heater is used, additional interlocks and precautions should beconsidered.




Street Address:

City:

State:

Zip:


Committee Statement

Committee Statement: Revised and added annex material based on FR-39-NFPA 87-2012.

Response Message:

Ballot Results


21 Eligible Voters

1 Not Returned

19 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


Brown, Amy

I think it should be made clear that flammable gases are only to be used with a pressurized (air tight) system.


297 of 302 7/7/2014 1:44 PM

First Revision No. 61-NFPA 87-2012 [ Section No. A.11.1, A.11.1.1.1, A.11.1.3, A.11.1.7,

A.11.2.1.1, A.11.2.1.2, A.11.2.1.5, A.11.2.1.6, A.11.2.1.7, A.11.2.1.9, A.11.2.2, A.11.2.2.2.1,A.11.2.2.2.5, A.11.2.3.2, A.11.2.4.2, A.11.2.4.3, A.11.2.4.4, A.11.2.4.8, A.11.2.4.9, A.11.2.4.10,A.11.2.4.11, A.11.3.1.1 ]

A.11.1

Class H heaters have heat source (combustion or electricity) inside the tube(s) with fluid surrounding thetube.

Class H fluid heaters present the following two major hazards:

(1) Uncontrolled release of the fluid, which can cause tube cracking or rupture, or pump seal failure,fire, or explosion which can result in fire or explosion

(2) Combustible accumulation and explosion Release and accumulation of combustible fuel gas orliquid, followed by ignition and explosion

A.11.1.1.1

Balanced flow is typically achieved by the piping geometry or fixed flow restrictions. If fluid flow ratesfall below the designed minimum flow rate, fluid overheating and subsequent degradation can occur.


A.11.1.3


A.11.1.7

Three-way valves or an automatic process equipment bypass can be used to maintain the minimumflow through the heater.

A.11.2.1.1

Air-cooled or water-cooled pumps with mechanical seals, canned motor pumps, seal-less pumps,and pumps that are magnetically coupled are examples of pumps that are used. If magneticallycoupled pumps are used, over-temperature protection of the pump coupling location should beprovided. Packing-based seals are prone to leakage and are not recommended. The pump materialselection should take into account the possible thermal shock experienced under fire suppressionscenarios.

A.11.2.1.2

The fluid manufacturer and the heater manufacturer should be consulted to providerecommendations on the appropriate pump for the application.

A.11.2.1.5

Loss of cooling can cause seal failure and a subsequent fire hazard.

A.11.2.1.6

Misalignment can cause seal failure and a subsequent fire hazard.

A.11.2.1.7

The alignment of the pump can change during the transition from cold to operatingtemperatures.

A.11.2.1.9

Examples of devices to protect pumps can be drip legs, strainers, filters, and screens.

A.11.2.2

If the fluid being relieved is combustible, measures should be taken to prevent ignition of thevapors or aerosols from the vent. Additional guidance can be found in NFPA 30, Flammableand Combustible Liquids Code .

A.11.2.2.2.1

Containment vessels for liquids include drain tanks, fill tanks, supplemental storage tanks,and catch tanks.


298 of 302 7/7/2014 1:44 PM

A.11.2.2.2.5

Secondary containment of effluent containment vessel should be considered if the fluid isflammable or hazardous.

A.11.2.3.2

Gate and ball valves can be used for isolation purposes, and globe or wafer-style butterflyvalves can be used for throttling purposes.

A.11.2.4.2


A.11.2.4.3

The operating temperature, the expansion coefficient of the fluid, and the system volumeare used to calculate the volume of the expansion tank. Some vapor space should remainin the tank when the system is at operating temperature. If the tank operates atatmospheric pressure and is located outdoors, an inert gas blanket should be consideredto minimize moisture ingress into the system. For very large systems, where expansiontanks are elevated and working volume exceeds 1000 gallons, a secondary, ground-levelcatch/storage tank and refill pumps can be used to take up excess expansion volume.

A.11.2.4.4

In addition to the low-level interlock, on large-volume systems, it is good practice to usedynamic leak detection (rate of change monitoring) on expansion tanks. Dynamic leakdetection is encouraged because it will detect abnormal fluid loss over time whereas alow-level switch is a single set point and often located just above tank empty. In somesituations, expansion tanks can be several thousand gallons in capacity. Therefore, ifonly low-level monitoring is provided, several thousand gallons could escape the systembefore the alarm is sounded. With dynamic leak detection, alarm notification of the fallingoil level will be made much sooner.

A.11.2.4.8

Nitrogen is typically used as the inert blanket. Other gases, such as carbon dioxide,may be used. In the oil and gas industry it is common to use flammable gases. If usingflammable gases, other precautions can be required, such as area classification andexplosion-proof electrical devices.

A.11.2.4.9

Consideration should be given to pressure surges that can occur during processupsets that can expose the expansion tank to pressures greater than 15 psi. Anexample of a common process upset is the rapid pressure rise due to water flashing tosteam. For this reason, many users specify expansion tanks that meet therequirements of ASME Boiler and Pressure Vessel Code , Section VIII Division 1.

A.11.2.4.10

A blanket gas low-pressure interlock should be considered where low blanket gaspressure can create a fluid heater system hazard.

A.11.2.4.11

See A.11.2.4.10 .

A.11.3.1.1

Detecting only flow/no flow conditions is not adequate. A pressure switch at thepump discharge and a pump rotation switch are examples of proving devices thatare not recommended to prove minimum flow as unexpected blockages in theheater tubes will not be detected by these devices.

Orifice plate(s) located at the outlet of a fluid heater and used with differentialpressure interlock(s) are a reliable way of proving the minimum flow. If pressuredrop across the heater is used, additional interlocks and precautions should beconsidered.




Street Address:


299 of 302 7/7/2014 1:44 PM

City:

State:

Zip:


Committee Statement

Committee Statement: Revised and added annex material based on FR-40-NFPA 87-2012.

Response Message:

Ballot Results


21 Eligible Voters

1 Not Returned

18 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


Brown, Amy

I think it should be made clear that flammable gases are only to be used with a pressurized (air tight) system.

Hudson , James G.

Quiescent bath heaters are not covered by the recommended practice.


300 of 302 7/7/2014 1:44 PM

First Revision No. 54-NFPA 87-2012 [ New Section after D.1.2.1 ]


D.1.2.2 ASME Publications.

American Society of Mechanical Engineers, Three Park Avenue, New York, NY 10016-5990.

ANSI/ASME B31.3, Process Piping , 2008.




Street Address:

City:

State:

Zip:


Committee Statement

CommitteeStatement:

Added reference due to FR-12-NFPA 87-2012. This section is not replacing any section,renumber subsequent sections.

ResponseMessage:

Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


301 of 302 7/7/2014 1:44 PM

First Revision No. 56-NFPA 87-2012 [ New Section after D.1.2.3 ]


D.1.2.5 IEC Publications.

International Electrical Commission, 3 rue de Varembé, P.O. Box 131, CH - 1211, Geneva 20,Switzerland.

IEC 61511, Functional Safety: Safety Instruments Systems for the Process Industry Sector , 2004.




Street Address:

City:

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Zip:

Submittal Date: Thu Nov 29 00:04:24 EST 2012

Committee Statement

Committee Statement: Added reference in FR-46-NFPA 87-2012.

Response Message:

Ballot Results


21 Eligible Voters

1 Not Returned

20 Affirmative All



0 Abstention

Not Returned

Wechsler, Tom ,

Affirmative All


302 of 302 7/7/2014 1:44 PM

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