hot water supply requirements

7/28/2019 Hot Water Supply Requirements

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Rules and Regulations Food Service Chapter 290-5-14Manual for Design, Installation and Construction

SECTION K - HOT WATER SUPPLY REQUIREMENTS

I. Background:

1. Purpose:

A. A critical factor in preventing foodborne illnesses in a food facility is the provisionof an adequate supply of hot water for the washing of hands, utensils, equipment,and the facility itself. The installation of a properly sized water heater will ensurethat a sufficient amount of hot water will be available at all times.

B. The purpose of these guidelines is to provide a set of criteria that will assistarchitects, designers, contractors, establishment owners and food service permitapplicants in the proper sizing of water heaters to adequately meet the anticipated

hot water demands of food facilities in Georgia. Similarly, these guidelines areprovided to aid the Health Authority or the County Environmental Health Specialist(EHS) during the plan review process to obtain reasonable assurance of theadequacy of the food establishments water heating equipment capacity to meet thedemand of the establishment. Food facilities with water heaters sized according tothese criteria should be capable of complying with the requirements for providingan adequate hot water supply as required by the Georgia Food Service Rules andRegulations Chapter 290-5-14-.06 subsection (1) (h) 2.

2. General Requirements:

A. All newly constructed or existing buildings being converted into a food serviceestablishment shall be provided with a hot water supply dedicated to the foodservice operation sufficient to satisfy the continuous and peak hot water demands ofthe food establishment at all times the establishment is in operation. Hot water forhand washing shall be tempered water at a temperature between 100F and 110F(43C) through a mixing valve or combination faucet. Depending upon the designof the machine, the temperature of wash solution in spray-type warewashers thatuse hot water to sanitize must be 150F (66c) to 165F (74c) for washing and

REFERENCES (Chapter 290-5-14)

.06 Sanitary Facilities and Controls. Amended. (1) Water (h) Capacity 2

.06 Sanitary Facilities and Controls. Amended. (2) Plumbing (c) Hand Sink Installation.

.05 Equipment and Utensils. Amended. (6)Maintenance and Operation (j) Mechanical Warewashing 1& 2

.05 Equipment and Utensils. Amended. (2)Design and Construction (bb) 1

.05 Equipment and Utensils. Amended. (6) Maintenance and Operation (l) Mechanical Warewashing 1

.05 Equipment and Utensils. Amended. (6) Maintenance and Operation (n) Manual & Mechanical Warewashing.


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165F (74c) to 180F (82c), not to exceed 194F (90c), for sanitizing. Themaximum sanitizing temperatures of 165F (74c) to 180F (82c), not to exceed

194F (90c) do not apply to high pressure and temperature systems with wand-type, hand-held, spraying devices used for in-place cleaning and sanitizing ofequipment such as meat saws. The temperature of the wash solution in spray-typewarewashers that use chemicals to sanitize shall not be less than 120F (49c). Thewater temperature for manual hot water sanitization must be at least 171F (77c).For the purposes of sizing hot water generating capability of the food serviceestablishment, a supply temperature requirement of 140F must be provided at eachfixture and to the mechanical dishwashing machines. This is needed to enablewarewashing machine booster heaters to operate satisfactory and to ensure adequatehot water for cleaning and sanitizing operations. Further, water heaters and theirinstallation must be in compliance with all Federal, State and local building and

plumbing code requirements and water heaters that use reclaimed heat fromequipment to heat water must be evaluated on a case-by-case basis.

I I. Storage Tank Type Water Heaters:

1. Sizing Requirements for Storage Tank Water Heaters:

A. For food facilities that utilize multi-service eating and drinking utensils, the waterheater shall have the ability to provide hot water at a rate equal to or greater than100% of the computed peak hourly hot water demand of the establishment, in gallonsper hour (GPH).

B. For food facilities that use only single-service eating and drinking utensils, or do notuse utensils at all, the water heater shall have the ability to provide hot water at a rateequal to or greater than 80% of the computed hourly peak hot water demand of theestablishment, in GPH.

C. The hourly hot water demand for the food facility, in GPH, is based upon a twenty-four hour basis and it is calculated by adding together the estimated hot waterdemands for all sinks and other equipment, such as dishmachines, which utilize hotwater. In the absence of specific hot water usage figures for equipment, as givenwithin manufacturers equipment specification sheets, Table K-1 and notes to TableK-1 shall be used to calculate peak hot water demand See Appendix J within PART-

II of this Manual for Peal Hourly Hot Water Demand Calculation Worksheet.The hotwater demands for automatic warewashers, such as dishmachines, glasswashers, andpotwashers are found in NSF International listings or listings established by othernationally recognized testing laboratories.


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TABLE K-1

PEAK HOURLY ESTABLISHMENT HOT WATER DEMAND

Equipment Type Gallons Per Hour Quantity Gallons/hour/day Totals

Vegetable sink _____ X 15 = ______Single food prep sink _____ X 20 = ______Double food prep sink _____ X 40 = ______3 - Compartment Pot sink _____ X 60 = ______4-Compartment Pot Sink _____ X 80 = ______Pre-rinse for dishes-shower head type _____ X 45 = ______Bar sink three-compartment _____ X 25 = ______Chemical sanitizing glasswasher _____ X 60 = ______Lavatory _____ X 5 = ______

Cook sink _____ X 10 = ______Hot water filling faucet _____ X 15 = ______Bain Marie _____ X 10 = ______Coffee urn _____ X 5 = ______Kettle stand _____ X 5 = ______Garbage can washer _____ X 50 = ______

Janitors sink _____ X 15 = ______Utility or Curbed cleaning facility _____ X 20 = ______Nine and twelve pound clothes washer _____ X 45 = ______Sixteen pound clothes washer _____ X 60 = ______**(Clothes washers See Note #2)Employee shower _____ X 20 = ______**Warewashing machine (See note #1) _____ X ________ = ______**Hose Reels (See note #3) _____ X ________ = ______Other Equipment (See note #4) _____ X ________ = ______

Peak Hourly Hot Water Demand =(_________)


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Notes to Table K-1Note #1: Hot water demand for warewashing machines shall be 100% as per ANSI/NSFI listings.Note #2: Clothes Washer Calculation:

A. Limited Use/Clothes washer used one to two times per day; beginning orending of day operation GPH =[60 (for16lb.) & 45 (for 9lb. to 12 lb.)] GPH x 25%.

B. Intermediate Use/Clothes washer used three to four times per day;GPH =[60 (for16lb.) & 45 (for 9lb. to 12 lb.)] GPH x 45%.

C. Heavy Use/Clothes washer used once every two hours; GPH =[60 (for16lb.)& 45 (for 9lb. to 12 lb.)] GPH x 80%.

D. Continuous Use/Clothes washer used every hour; GPH =[60 (for16lb.)& 45 (for 9lb. to 12 lb.)] GPH x 100%.

Note #3: Hose reels @ 20 GPH for first reel & 10 GPH for each additional reel.

Note #4: Other equipment not listed in Table E-1 shall be as per the manufacturersequipment specification sheets.

D. The following examples are provided to explain how to calculate the total hourly hotwater demand:

(1). Food facility that utilizes only single service eating and drinking utensils:

Assume:

1 X Three compartment sink @ 60 GPH = 60 GPH2 X Hand lavatories @ 5 GPH each = 10 GPH (5 GPH each)1 X Janitorial sink @ 15 GPH = 15 GPH

Total hourly hot water demand = (85 GPH)

(85 GPH) X 80% allowance for single-service utensils = (68 GPH)

For the food facility in this example, a water heater would be required, which willhave enough British Thermal Units (BTU) (if gas operated) or Kilowatts (KW) (ifelectrically operated) size rating to recover 68 Gallons per Hour (GPH).


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(2).Food facility that utilizes multi-service eating and drinking utensils:

Assume:1 X Three-compartment sink @ 60 GPH = 60 GPH1 X Warewashing dish machine @ 80 GPH = 80 GPH1 X Hand spray pre-rinse @ 45 GPH = 45 GPH1 X One-Compartment food prep sink (20 GPH) = 20 GPH2 X Hand lavatories @ 5 GPH each = 10 GPH1 X Janitorial sink @ 15 GPH = 15 GPH

Total hourly hot water demand = (230 GPH)

Since the food facility in this example uses multiservice eating and drinkingutensils, 100% of the computed hourly hot water demand must be provided.

Therefore, a water heater would be required that has the capability to recover230 Gallons Per Day (GPH).

E. The following are examples for determining the energy input (BTU for gas waterheaters) and KW (kilowatts for electric water heaters):

(1). Electric Water Heater Sizing:

Given: The peak hot water demand for an establishment has been calculated to be68 GPH. An electric water heater with a kilowatt (KW) input rating of 14 KWhas been specified within the food service plans for review. We need to verify

whether or not the proposed water heater is correctly sized.

Formula: KW input =GPH X 100F Rise X 8.33 lb. per gallon of waterThermal Efficiency (See Note#1) X 3412 BTUs/ KW

Note #1: The thermal efficiency for electric water heaters, unless otherwiselisted by ANSI/NSFI will be assumed to be 98% or.98.

Example: KW input =68 X 100 X 8.33.98 X 3412

=16.9402 or (17 KW)

In this example, you will need an electric water heaterwith a kilowatt rating of atleast 17 KW. The foodservice plans for review did not specify such a water heateras calculated. Therefore, the heater would not be compatible with the demands ofthe establishment. A water heater with at least 3 KW (17 KW 14 KW = 3 KW)additional KW capacity will be needed to meet the establishment hot water peakdemand.


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(2). Gas Water Heater Sizing:

Given: The peak hourly hot water demand for an establishment has beencalculated to be 230 GPH. A gas water heater with a BTU input of rating of218,802 BTUs has been specified within the food service plans for review.We need to verify whether or not the proposed water heater is correctly sized.

Formula: BTU input =GPH X 100F Rise X 8.33 lb. per gallon of waterThermal Efficiency (See Note#2)

Note #2: The thermal efficiency for gas water heaters, unless otherwise listed byANSI/NSFI will be assumed to be 75% or.75.

Example: BTU input =230 X 100 X 8.33 =255,453.3333 or (255,453 BTU input).75

In this example, you will need a gas water heater with a BTU input energy ratingof255,453 BTUs. The foodservice plans for review did not specify the waterheater as calculated; therefore, you cannot assume the heater would be compatiblewith the demand of the establishment. A water heater withat least 36,651(255,453 BTU 218,802 BTU = 36,651 BTU) additional BTU capacitywill beneeded to meet the establishments hot water peak demand.

II I. Requirements for Booster Heaters:

1. General Requirements:

A. When a hot water sanitizing warewashing machine is used, a booster heater must beprovided that will raise the incoming general-purpose hot water at a temperature of140 Fahrenheit up to at least 180 Fahrenheit for the final sanitizing rinse cycle.Booster heaters shall be sized at a 40 Fahrenheit rise. Booster heaters may beincorporated within the design of the warewasher or be added as a separate unit atthe warewashing machine.

B. When sizing a booster heater, the hot water demand for the warewashing finalsanitizing rinse cycle should be obtained from the NSF International listings or

listings established by other nationally recognized testing laboratories.

C. Use the following formulas when sizing warewashing machine booster heaters:

(1). Electric Booster Heater Sizing:


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Given: A hot water sanitizer warewashing machine with a final rinse hot waterdemand of 100 gallons per hour (GPH) is specified in plans for review.

An electric booster heater with a kilowatt (KW) input rating of 10 KWhas been specified within the food service plans for review. We needto verify whether or not the proposed booster heater is correctly sized.

Formula: KW input =GPH X 40F Rise X 8.33 lb. per gallon of waterThermal Efficiency (Note#3) X 3412 BTUs/ KW

Note#3 The thermal efficiency for electric booster heaters, unless otherwiselisted by ANSI/NSFI will be assumed to be 98% or.98.

Example: KW input =100 X 40 X 8.33

.98 X 3412

=9.964 or 10 KW

In this example you would need an electric booster heater with a kilowattrating of 10 KW. The foodservice plans for review specified such a boosterheater for the warewasher specified as calculated. You can now assume thebooster heater would be compatible with the demand of the warewasher.

2. Gas Water Heater Sizing:

Given: A hot water sanitizer warewashing machine with a final rinse hotwater demand of 100 gallons per hour (GPH) is specified in plans forreview. A gas booster heater with a BTU input rating of 10 KW hasbeen specified within the food service plans for review. We need toverify whether or not the proposed booster heater is correctly sized.

Formula: BTU input =GPH X 40F Rise X 8.33 lb. per gallon of waterThermal Efficiency (See Note#4)

Note #4 The thermal efficiency for gas booster heaters, unless otherwiselisted by ANSI/NSFI will be assumed to be 75% or.75.

Example: BTU input =100 X 40 X 8.33.75

=44,426.6666 or 44,427 BTU input


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In this example, you would need a gas booster heater witha BTU input energyrating of at least 44,427 BTUs. The foodservice plans for review specified

such a booster heater for the warewasher specified as calculated. You cannow assume the booster heater would be compatible with the demand of thewarewasher.

D. When a booster heater is installed below a drainboard, it shall be installed at least sixinches above the floor and away from the wall, and in a manner that will allowaccessibility for proper cleaning and servicing.

IV. Installation Requirements:

1. Recirculation Pump:

A. Where fixtures are located more than sixty feet from the water heater, it maybecome necessary to install a recirculation pump, in order to ensure that waterreaches the fixture at required temperatures. Should it be shown by food serviceestablishment planner to the satisfaction of the health authority that piping fromwater heaters can be effectively insulated to prevent significant heat loss beforereaching fixtures, the requirement of a recirculation pump will not be necessary.

2. Water heaters shall be mounted in one of the following manners:

A. On six-inch high, easily cleanable legs.

B. On a four inch high coved curb base. All openings between the water heater and thebase must be sealed in a watertight manner.

C. On a properly finished and installed wall pedestal, positioned so that it is out of thework and traffic space.

D. In an easily accessible location above a suspended ceiling. A permanently installedladder will be required to access water heaters located above suspended ceilings;the ladder shall not be installed above food or utensil handling areas.

Note: The Health Authority may allow alternate installation methods when awater heater is installed in an area separated from food and utensilhandling areas, such as in a mechanical room. Local Building Codes shouldbe consulted.

3. Common Mistakes Residential Water Heaters:


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A. A common mistake with electric water heaters is the ordering and installing of awater heater with an upper element of 4500 watts, a bottom element of 4500 watts,and a total connected (or maximum) wattage of 4500 watts. On such a water heater

only one element is operating at any one time. Many individuals do not observe thetotal connected wattage and assume that because each of the elements is 4500 wattstheir water heater has an input rating of 9000 watts. Water heater manufacturershave specific procedures for rewiring an electric water heater so that the upper andlower elements are operating simultaneously. Some manufacturers only permitrewiring in the factory. Field modifications will normally void warranties and anylistings that the unit comes with. Prior to acceptance of a field modified waterheater, the local health agency should ensure that the modifications were performedaccording to the manufacturer's recommendations and with the approval of the localbuilding officials. The data plate on a field modified water heater must be changedto reflect the total connected wattage rating with both elements operating

simultaneously.

V. Instantaneous-Tankless-Water-Heaters:

1. Background:

A. It is common for food service establishments to use appliances and equipment thatutilize natural gas as a source of energy to operate. Equipment such as grills, deepfryers and water heaters commonly use gas to cook foods and to heat water. Overthe recent years, the cost of natural gas and other energy resources coupled withrising food production cost has brought to bare an increase in the operational cost ofmost food service establishments. As a result, these establishments, existing and

proposed, are searching to find ways to lower these costs so they can better competein todays market. One of the ways food service establishments can cut operationalcost is to utilize equipment and appliances that are energy efficient.

B. Just like in the home, the cost of heating water is only second to that of operatingair-conditioning. This pressure to reduce the cost of heating water within the homehas created a need for innovation and as a result, industry has responded bydeveloping a different kind of water heating appliance - one that only operates asresult of demand, meaning it only heats water when it is requested to do so by thehomeowner. And how does this new kind of water heating appliance reduce cost ofheating water? The conventional water heater stores water in a tank and

continuously consumes energy to maintain a set water temperature until the heatedwater is needed. The arrival of the instantaneous-tankless-water-heater only usesenough energy to heat water as it is needed; thereby, it utilizes far less energy thanthe traditional standard storage tank style water heater, providing the homeownerwith substantial energy cost savings over time. It is this substantial energy costsavings that makes instantaneous-tankless-water-heaters attractive to current andprospective food service establishment operators and the industry has responded bymanufacturing models for use in their establishments.


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C. One of the advantages of an instantaneous-tankless-water-heater is its ability toprovide a continuous supply of hot water. However, since the water passes through

a heat exchanger, the water must flow through the unit slowly to assure proper heattransfer. Therefore, the quantity or rate at which the hot water is delivered can besignificantly less than that provided by a storage-tank-style-water-heater. When hotwater is utilized at several locations of the food facility at the same time, the flow ofhot water to each fixture can be severely restricted. As a result and depending onthe numbers and types of sinks and equipment utilizing hot water being present,more than one of these types of water heaters may be required to keep up withestablishment demand for hot water.

D. Instantaneous-tankless-water-heaters are designed to operate by injecting enoughBTUs (British Thermal Units) into water as it flows by a heating coil or exchanger

at a given rate. As such, their ability to meet demands placed on them for hot waterdepends on the design flow rates of equipment and fixtures utilizing hot water tooperate properly. Therefore, it is imperative that instantaneous-tankless-water-heaters be sized to meet the peak hot water flow rate and volume demand of the hotwater side of the potable water plumbing system of the proposed establishment.Once these systems have been designed to meet this stated peak demand in hotwater, any future changes in equipment and fixtures, such as the act of removingaerators from faucets or the installation of a piece of equipment with a higher GPMrating by the establishment operator, will cause such systems to be undersized and aresulting inadequate hot water supply for the establishment. This occurrence of thelack of adequate hot water generation ability within the establishment will cause

cleaning and sanitization problems for the establishment. To correct any undersizing effects due to an increase within the peak demand flow and volume rate ofthe hot water side of the establishments potable water plumbing system, it maybecome necessary to increase the water heating systems design flow and volumerate to meet this new demand. The food service inspector must realize that it is themanufacturer of the food service equipment, such as warewasher and or fixturesthat are installed on sinks, who determine the flow and volume rates for theirequipment and fixtures. These manufacturer flow and volume rates are dependentupon the equipment and or fixture design and configuration as shipped from themanufacture and any changes made in the field could have an adverse effect on howthe water heating system functions. Once an instantaneous-tankless-water-heatersystem has been properly designed by its manufacturer and or distributor and hasbeen shown by the establishments professional plans and specification preparer tomeet the peak demand of the hot water side of the potable water system of theproposed food service establishment, close observation of changes made to fixturesand equipment is noted during inspections where such instantaneous-tankless-water-heaters are installed.


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2. General Sizing and Installation Requirements:

A. If utilized instead of the traditional storage tank type water heaters and/or whether

configured in single or combined units, instantaneous-tankless-water-heaters andassociated distribution systems shall be sized appropriately. They shall be sized soas to be capable of generating a supply of hot water at a temperature of at least 140Fahrenheit to all sinks, janitorial facilities, and other equipment and fixtures that usehot water, at all times. This hot water supply being generated must meet or exceedthe peak hot water flow and volume rate demand, expressed as GPM (Gallons perMinute), throughout the food service establishment. Hot water at a temperaturebetween 100 and 110 Fahrenheit shall be provided to each hand-washing lavatorythrough a mixing valve or combination faucet. Peak hot water flow and volumerate demand of the hot water side of the potable water plumbing system is definedas being equal to the combined total of the manufacturers design flow and volume

rate specification(s) for each piece of equipment and fixture at the potable waterplumbing systems designed operating pressure in psi (pounds per square inch)utilizing hot water within the proposed establishment.

B. When sizing instantaneous, tankless style water heater systems, specialconsideration must be given to certain fixtures, such as, pre-rinse nozzles at threecompartment sinks and warewashers, mop sinks or hosebibbs, used for cleaningoperations whereby hot water is used in flushing or rinsing operations. For suchdescribed fixtures, a minimum of 1 GPM will be used for each such fixture whencalculating the peak demand flow and volume rate of the hot water side of theestablishments potable water plumbing system. Should more specific gallon perminute (GPM) flow and volume rate be listed within the manufacturers

specification documentation for fixtures and equipment that is greater than theminimum 1 GPM, then the greater figure will be used in sizing the water heatingsystem.

(Note: Hand lavatories and hand sinks must receive at least GPM flow rate.)The following example is provided to explain how this sizing criterion isapplied:

(Example #1)

Assume:

1 Three compartment Sink 2.0 GPM2 Hand Lavatories @ 0.5 GPM 1.0 GPM1 Janitorial Sink 1.0 GPM1 Vegetable Sink 2.0 GPM

Total Peak Demand (6. 0 GPM)


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In the Example #1, it is possible that one instantaneous-tankless-water-heater couldbe provided in order to supply a total peak flow and volume demand of not less than6.0 GPM with a N-132 Model Unit.

(Example #2)

Assume:

1 Three compartment sink 2.0 GPM5 Hand lavatories @ GPM 2.5 GPM1 Janitorial sink 1.0 GPM1 vegetable sink 2.0 GPM1 Warewasher (rated at 3.6 GPM) 3.6 GPM

Total Peak Demand (11.1 GPM)

In the Example #2, a bank of units consisting of two or more instantaneous-tankless-water-heaters would have to be provided in order to supply a total peak flow andvolume demandof not less than 11.1 GPM.

C. To insure whether or not instantaneous-tankless-water-heater systems will meet hotwater peak flow and volume demand throughout the food service establishment,food service plans for review must be provided with the water systemmanufacturer's specification sheets. These sheets must indicate the graphicalperformance curve(s) based on specific models, the degree rise (defined as 140

Fahrenheit water at equipment and fixtures) minus the degree Fahrenheittemperature of incoming water to the establishment at the coldest season of anyyear, as reported by the local water authority and gallons per minute flow rates. SeeFigure K-1 for an example of an instantaneous-tankless-water-heater performanceflow chart. Further and in conjunction with the required graphical representation ofmodel performance, a spreadsheet indicating numerical values for flow rates permodel must be included within the instantaneous water heater specificationdocumentation. (See Figure K-2 for an example).


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Flow Chart

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

12.0

13.0

14.0

20 30 40 50 60 70 80 90 100

110

120

130

Temperature Rise (F)

Flow

Rate(GPM)

N-132M

N-084

N-069M

N-063S

6.2 gpm

FIGURE K-1

FIGURE K-2

FIGURE K-1


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FIGURE K-2

Temp Rinse N-132M N-084 N-069M N-063S

20 13.2 8.4 7.9 6.3

25 13.2 8.4 7.9 6.3

30 13.2 8.4 7.9 6.3

35 13.2 8.4 7.9 6.3

40 13.2 8.4 7.9 6.3

45 13.2 8.4 6.9 6.350 12.5 7.8 6.3 6.3

55 11.3 7.1 5.6 5.6

60 10.4 6.5 5.2 5.2

65 9.6 6.0 4.8 4.8

70 8.9 5.5 4.4 4.4

75 8.3 5.2 4.1 4.1

80 7.8 4.8 3.9 3.985 7.3 4.6 3.7 3.7

90 6.9 4.3 3.5 3.5

95 6.6 4.1 3.3 3.3

100 6.2 3.9 3.1 3.1

105 5.9 3.7 3.0 3.0

110 5.7 3.5 2.8 2.8

115 5.4 3.4 2.7 2.7

120 5.2 3.2 2.6 2.6

125 5.0 3.1 2.5 2.5

130 4.8 3.0 2.4 2.4


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D. It should be noted that by examining the typical performancegraph in Figure K-1

and the chart in Figure K-2, that each unit model of instantaneous-tankless-water-heaters tend to drop-off in hot water production (gallons per minute flow andvolume rate) at various rates with each increase in degree rise variation. This drop-off in hot water production with each increase in degree rise variation per unitmodel is why you must know what the lowest temperature of incoming water to theunit or bank of units is at the coldest time of the year. Without this degree risetemperature determination, the water heating systemcannot be correctly sized. It isstrongly recommended that planers of these stated water-heating systems consultwith the local water distribution authority servicing the location of the proposedfood service establishment to document the incoming water temperature enteringthe establishment. In areas of Georgia where there is no water distribution system

authority to consult with and or where an approved well is utilized as theestablishments potable water supply, it may become necessary to rely on publishedground water data or actually measure incoming water temperature at theestablishment. In these stated cases where wells are utilized for water supply to theproposed establishment, an engineer, an architect, a master plumber or well drillercontractor, all licensed by the State of Georgia, will need to verify and documentthe incoming water temperature to the establishment and this documentation mustbe included within the food service plans and specifications upon submittal to thehealth authority for review.

E. Food facilities that install an automatic warewashing machine that utilizes a large

quantity of hot water may be required to provide an instantaneous-tankless-water-heater exclusively for the warewashing machine or incorporate a hot waterrecirculation system from the water heating system to the warewasher.instantaneous-tankless-water-heaters shall not be substituted for ware washingmachine booster heaters for hot water sanitizing. ANSI/NSFI (American NationalStandards Institute/National Sanitation Foundation International) listings are used todetermine the minimum GPM hot water demand for automatic warewashingmachines - see Figure K-3or while on the Internet, click ontohttp://www.nsf.org/business/search_listings/index.aspfor an example of suchlistings. Should these stated listings not be available for a particular make andmodel of warewashing machine or other equipment utilizing hot water, it shall bethe responsibility of the food service plans preparer to provide the manufacturersspecification sheets giving the equipment design GPM flow rate operatingrequirements for hot water.


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FIGURE K-3

HOBART CORPORATIONWORLD HEADQUARTERS

701 SOUTH RIDGE AVENUE

TROY, OH 45374937-332-2836

Facility: DANVILLE, KY

STATIONARY RACK DISHWASHING MACHINESFinal Rinse

(20 psi) Operating Time Model Rack Size Flow Usage (seconds) Footnotes

Number Width gpm gph Wash Rinse Dwell

Single Tank Chemical Sanitizing DoorAM-14 20x20 8 96 27 9 4 [4] [5] [6] [7]AM-14 20x20 8 74.4 40 9 4 [4] [5] [6]AM-14C 20x20 8 72 40 9 4 [4] [5] [6]AM-14C 20x20 8 91.2 27 9 4 [4] [5] [6] [7]

AM-14F 20x20 5.67 56.8 40 15 4 [4] [5] [6]AM-14F 20x20 5.67 66.7 27 15 4 [4] [5] [6] [7]AM-14T 20x20 5.67 79.5 40 15 4 [4] [5] [6]AM-14T 20x20 5.67 99.4 27 15 4 [4] [5] [6] [7]AM-14TC 20x20 5.67 95.1 27 15 4 [4] [5] [6] [7]AM-14TC 20x20 5.67 76.7 40 15 4 [4] [5] [6]LT-1 20x20 62 70.3 41 22 27 [4] [6]

[4] Optional tabling and shelving fully complying with NSF Standard 2 may be provided.[5] Unit specified must have letter "L" following serial number on machine data plate.[6] Final rinse must contain 50 ppm minimum available chlorine.

[7] Models with a shorter wash cycle (reduced 12 seconds) require a minimum wash temperatureof 130F.


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3. Recirculation Pumps:

A. The term cold water sandwich effect is a term that is used to describe the

introduction of cold water into the hot water supply line during frequent on/offoperation of an instantaneous-tankless-water-heater. The cold-water sandwicheffect, when present, appears as a momentary drop in hot water temperature as it isdischarged from a hot water supply outlet (i.e. restaurant hand lavatories, mopsinks, warewashing machines, etc.). This phenomenon is present in the operation ofall instantaneous-tankless-water-heaters and it is a direct result of their operatingprinciples used to heat water.

B. The development of instantaneous-tankless-water-heaters required a departure fromthe common tank type storage water heater. Tank type water heaters heat a storedvolume of water slowly over a long period of time (approximately 1 hour) and then

maintain this stored water at a high temperature until used. It is the elimination ofstored water from hot water systems that has resulted in the cold-water sandwicheffect.

C. For a better understanding of why a cold-water sandwich effect exists withinstantaneous-tankless-water-heaters, the operating principles and safetymechanisms involved in their operation must be understood. The basic operation ofall instantaneous-tankless-water-heaters as follows:

(1.) Water flow sensor senses water flow through the heater.

(2.)

Burner ignition is initiated resulting in the production of hot water.

(3.) Water flow and temperature is monitored and used to adjust the flow of gas tothe burner, so that the outlet set point temperature is maintained.

(4.) When water flow ceases, the water heater shuts off. To maintain a safeignition sequence, steps (A) and (B) typically take up to 10 seconds. Duringthis ignition sequence, a small amount of cold-water flows through the waterheater. When hot water usage is stopped briefly and then started up again, thisignition sequence is repeated, and the small amount of cold water that passesthrough the water heater forms a cold water sandwich. It is this sequence ofoperations with these water-heating systems that cause a brief cold-waterdischarge at sinks and equipment until the unit has caught-up with the hotwater demand at the point of discharge(s) from within the hot water side of thepotable water plumbing system. It should be noted that the cold-watersandwich effect cannot be removed completely from instantaneous, tanklessstyle water heater systems. The safety standards developed to insure the safeoperation of water heaters require a delay in the ignition sequence of all gas


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water heaters. In addition, electric type, instantaneous-tankless-water-heatersystems too can experience this cold-water sandwich effect due to the time it

takes the heating elements to be energized and reach heating temperatures.

(5.) It is for the cold water sandwich affect that where fixtures are located morethan sixty feet from the water heater, a recirculation pump with reserve tankmay be considered as part of the instantaneous-tankless-water-heater systeminstallation, in order to ensure that water reaches the fixture at a temperatureof at least 140F. This requirement is applicable to all applications, unless theinstantaneous-tankless-water-heating system designer can satisfactorilyincorporate other means within the system design to insure a constant flow ofhot water at each hot water discharge point within the hot water side of thepotable water plumbing system at the plumbing systems design operating

pressure. On a case- by-case basis, it may be more practical to install aseparate, water heater for high hot water flow demand equipment. In othercases, it may be more practical to install a separate, smaller instantaneous-tankless-water-heater at remote fixtures, such as for restroom hand sinks.

4. Installation Requirements:

A. The installation of instantaneous-tankless-water-heaters must follow the followingguidelines:

(1). instantaneous-tankless-water-heater systems are site fixture and specific in

their design; therefore, they must be designed based on equipment and fixturesspecified to be installed within the proposed or for those already installedwithin existing food service establishment.

(2). Where feasible, instantaneous-tankless-water-heaters should be located in anarea of the food facility separated from all food and utensil handling areas insuch a way it will not impede routine cleaning of the establishment or harborvermin. They must be installed in a location that facilitates the ease of accessto the unit or units for servicing and monitoring.

(3). Instantaneous-tankless-water-heaters must be installed according to anyapplicable codes or laws (Federal, State, Local, etc.).

(4). Instantaneous-tankless-water-heaters must be designed and built according tostandards set by American National Standards Institute (ANSI) accreditedcertification programs and others as per applicable plumbing or building codesor laws (Federal, State, Local) this will be determined by the water heatinginstallation passing applicable building and or plumbing inspections.


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(5). Instantaneous-tankless-water-heaters are properly sized when the total GPMof a single unit or the combined GPM of several units (bank of units) is equal

to or exceeds the peak hot water flow and volume, expressed as GPM(Gallons per Minute), demand throughout the food service establishment atthe designed operating pressure of the establishments potable water plumbingsystem.

(6). A Flow Meter shall be permanently installed adjacent to or incorporatedwithin the designed instantaneous-tankless-water-heater unit or units so as toprovide a means to monitor the flow rate in gallons per minute (GPM) withinthe food service establishments hot water side of the potable water plumbingsystem. The flow meter must give a numerical readout of the flow of water asit passes through the instantaneous-tankless-water-heater. The flow meter

must be durable and capable of maintaining its accuracy and of withstandingthe design operational temperatures and design pressures of the hot water sideof the potable water plumbing system. The purpose of this flow meter is toensure the continued compatibility of the water heating system with the hotwater peak demand flow and volume rate of the establishment.

(7). In the event of the replacement of a tank type water heater; or during theplanning of a new proposed food service establishment with an instantaneous-tankless-water-heater system;or where no data isavailable for existingfixtures and equipment that uses hot water, the health authority may request areport from an engineer, architect or master plumber who is licensed to do

work in the State of Georgia. Within this report, the licensed professional willlist each fixture and piece of equipment utilizing hot water by common name,make and model along with its corresponding flow rates in gallons per minute.In addition, said report will give the total combined gallons per minute flowrate of listed fixtures and equipment utilizing hot water at the establishmentspotable water systems designed operating pressure expressed as pounds persquare inch (PSI). The report will begenerated on the design professionalsletterhead and it will bare the designers name, title, date of report and hisState of Georgia professional license number.

hot water supply requirements

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