Confined Spaces

Confined Space Entry

•Construction Industry Standard 1926.21(b)(6)

•General Industry Standard1910.146

•Best Practices for all Industries

Typical Confined Spaces

• Boiler, Degreaser, Furnace• Pipeline, Pit, Pumping Station• Reaction or Process Vessel, Mills• Septic Tank, Sewage Digestor• Silo, Storage Tank, Barges• Sewer, Utility Vault, Manhole• Trenches, Shafts, Caissons

The Three Elements of a Confined Space

• Is large enough and so configured that an employee can bodily enter and perform assigned work; and

• Has limited openings for entry and exit, and

• Is not designed for continuous worker occupancy

Categorizing Work Space

* Space large enough to enter &;* Limited or Restricted entry or exit &;* Not designed for continuous worker occupancy.

NONot a confined Space

YES Confined Space

Hazardous Atmosphere

Engulfment Hazard

Configuration Hazard

Any other recognized serious hazard

Permit-

Required

Confined

Space

Non

Permit

Required

Space

YES NO

Or

Or

Or

Limited Openings for Entry/Exit

•Openings as small as 18 inches in diameter.

•Difficult to enter with SCBA or other life-saving equipment.

•Difficult to remove downed worker in folded up or bent over position.

•Exit from large openings may be difficult due to presence of ladders, hoists, etc.

Unfavorable Natural Ventilation

•Lack of air movement in and out of the space can create an atmosphere much different than the outside atmosphere.

•Deadly gases can be trapped inside.

•Organic materials can decompose.

•May not be enough oxygen due to presence of other gases or chemical reactions such as rusting.

Not Designed for Continuous Worker Occupancy

• Most confined spaces are not designed to enter and work in on a regular basis.

• Designed to store a product.• Enclose materials or processes.• Transport products or substances.• Occasional worker entry for inspection,

repair, cleanup, maintenance, etc.

Dangerous Combinations

•Presence of all three confined space characteristics can complicate the situation.

•Working in and around the space.

•Rescue operations during emergencies.

•Worsened conditions due to work activities: Welding and cutting, use of bonding agents Cleaning with solvents, use of other chemicals Use of gas-powered equipment

Hazards of Confined Spaces

•Oxygen Deficient Atmospheres

•Oxygen Enriched Atmospheres

•Flammable Atmospheres

•Toxic Atmospheres

•Temperature Extremes

•Engulfment Hazards

•Noise, Slick/Wet Surfaces, Falling Objects

Oxygen Deficient Atmospheres

19.5 % Minimum acceptable oxygen level.15 - 19% Decreased ability to work

strenuously. Impair coordination. Early symptoms.

12-14%Respiration increases. Poor judgment.10-12%Respiration increases. Lips blue.8-10% Mental failure. Fainting. Nausea

Unconsciousness. Vomiting.6-8% 8 minutes - fatal, 6 minutes - 50% fatal

4-5 minutes - possible recovery.4-6% Coma in 40 seconds. Death

Oxygen Enriched Atmospheres

•Oxygen level above 21%.

•Causes flammable and combustible materials to burn violently when ignited.

•Hair, clothing, materials, etc.

•Oil soaked clothing and materials.

•Never use pure oxygen to ventilate.

•Never store or place compressed tanks in a confined space.

Flammable Atmospheres

•2 Critical Factors: Oxygen content in the air. Presence of a flammable gas, or vapor Presence of dust (visibility of 5’ or less)

•Proper air/gas mixture can lead to explosion

•Typical Ignition Sources: Sparking or electric tool. Welding / cutting operations. Smoking

Toxic Atmospheres

•Product stored in a confined space: Gases released when cleaning. Materials absorbed into walls of confined space. Decomposition of materials in the confined space.

•Work performed in a confined space: Welding, cutting, brazing, soldering. Painting, scraping, sanding, degreasing. Sealing, bonding, melting.

•Areas adjacent to a confined space.

Hydrogen Sulfide

•Decomposition of materials. Human waste.

•Rotten egg odor at low concentrations.

•Possibly no warning at high concentrations.

PPM Effect Time10 ppm Permissible Exposure Level 8 Hours50 - 100 Mild Irritation - eyes, throat 1 Hour

200 - 300 Significant Irritation 1 Hour 500 -700 Unconsciousness, Death 1/2 - 1 Hour >1000 Unconsciousness, Death Minutes

Carbon MonoxideCarbon Monoxide

• Odorless, Colorless Gas.Odorless, Colorless Gas.

• Combustion By-Product.Combustion By-Product.

• Quickly collapse at high concentrations.Quickly collapse at high concentrations.

PPMPPM EffectEffect TimeTime 5050 Permissible Exposure LevelPermissible Exposure Level 8 Hours8 Hours

200200 Slight headache, discomfortSlight headache, discomfort 3 Hours3 Hours

600600 Headache, discomfortHeadache, discomfort 1 Hour1 Hour

1000-20001000-2000 Confusion, nausea, headacheConfusion, nausea, headache 2 Hours2 Hours

1000-20001000-2000 Tendency to staggerTendency to stagger 1 1/2 Hours1 1/2 Hours

1000-20001000-2000 Slight heart palpitationSlight heart palpitation 30 Min.30 Min.

2000-25002000-2500 UnconsciousnessUnconsciousness 30 Min.30 Min.

Temperature Extremes

•Extremely hot or cold temperatures.

•Steam cleaning of confined spaces.

•Humidity factors.

•Extremely cold liquids.

•Work processes inside the confined space can increase temperature extremes.

•Personal protective equipment.

Engulfment Hazards

• Loose, granular materials stored in bins and hoppers - grain, sand, coal, etc.

• Crusting and bridging below a worker.

• Flooding of confined space.• Water or sewage flow.

Other Hazards

•Noise Amplified due to acoustics within the

space. Damaged hearing, affect communication.

•Slick / Wet Surfaces Slips and falls. Increased chance of electric shock.

•Falling Objects Topside openings expose workers inside

confined space to falling objects.

Internal Configuration

Testing The Atmosphere

•Verify presence of safe work atmosphere.

•Test all areas of a confined space. Top, Middle, Bottom

•Methane is lighter than air.

•Carbon Monoxide is the same as air.

•Hydrogen Sulfide is heavier than air.

•Oxygen Deficiency.

Ventilation

•First option to correct problems.

•Must be aware of hazards you are trying to correct in the confined space.

•Air intake in a safe location to draw fresh air only.

•Continuous ventilation whenever possible.

•Retest the confined space before entry.

Isolation

•Locking and tagging out electrical sources.

•Blanking and bleeding pneumatic and hydraulic lines.

•Disconnecting mechanical drives and shafts.

•Securing mechanical parts.

•Blanking sewer and water flow.

•Locking and tagging out shutoff valves.

Respirators

•Air-Purifying Respirators Filter dangerous substances from the air. Must know the type and amount of hazardous

substance present in the confined space. NEVER use with oxygen deficiency!

•Air-Supplying Respirators Deliver a safe supply of breathing air from a

tank or an uncontaminated area nearby. Must be adequately monitored.

Permit Entry Systems

•Written permit signed by entry supervisor.

•Verifies pre-entry precautions have been taken and the space is safe to enter.

•Posted at entry to confined space.

•Specifies apparent hazards and corrective actions taken prior to entry.

•Requires termination of permit when task is completed or when new conditions exist.

Entry Permit Requirements

•Date, location, and name of confined space.

•Purpose of entry and known hazards.

•Duration of entry permit time.

•Authorized entrants, attendants, supervisors.

•Air testing results - signature of tester.

•Protective measures to be taken. Ventilation, Isolation, Flushing Lockout / Tagout, Purging

Entry Permit Requirements

•Name and phone numbers of rescue and emergency services.

•Communication procedures.

•Special equipment and procedures. Personal protective equipment. Alarm procedures. Rescue equipment. Respirators.

Standby / Rescue

•Worker assigned to remain outside the confined space and be in constant contact with the workers inside.

•Know emergency rescue procedures.

•50% of workers who die in confined spaces are would-be rescuers.

•Trained in use of emergency rescue equipment and PPE.

Training and Education

•All workers who must enter confined spaces

•All attendants and rescue team members.

•Prior to initial work assignment.

•Retraining: Job duties change. Change in permit-space program. New hazards are present. Job performance indicates deficiencies.

Confined Space Rescue Training Compliance

Issues

Most confined space fatalities are poorly trained rescuers…

Many of these heroes died because their employer unintentionally broke the law-OSHA regulations!

OSHA’s 3 levels of protection for confined space entrants:

1) Permitting procedure identifies

hazards and addresses protective

measures

2) Retrieval equipment required for

quick external rescue

3) Rescue services required to be

available to perform internal rescue

Employer shall ensure...

(i) The outside rescuer can effectively respond in a timely manner to rescue summons.(ii) The outside rescuer is equipped, trained, and capable of functioning appropriately to perform permit space rescues…(iii) …rescuer is aware of the hazards…(iv) …provide access...

Response Vs Rescue Time...

(1) React Time: Attendant recognizes that the Entrant has a problem.(2) Contact Time: Attendant contacts the Rescue Service.(3) Response Time:Rescue Service arrives at the scene.

Rescue Vs Response Time...

(4) Assessment Time:Size-up and strategy determination.(5) Preparation Time:Rescue equipment set-up.(6) Rescue Time:Reaching, treating, packaging, and evacuation of the victim.

Rescue Stand-by

Goal: 4-Minute Rescue ResponsePossible only if rescuers are rigged and ready while the entry is taking place. This is defined as Rescue Stand-by.

Rescue Available

Appropriate (and Approximate!) Goals: Respond To CS Scene / 10 MinutesReach The Victim(s) / 5-10 Minutes Later

Case law update….10 minute response held to be not timely in a Nov. 1997 case!

Choosing the Appropriate Response

Decision: Stand-by Vs. AvailableEach entry must be evaluated to determine the appropriate response mode.The evaluation must be done by a qualified person (rescuer and/or entry supervisor).Factors to be considered include the severity of the hazard, required PPE, and the ability of the entrant to self-rescue.

Timely Response, Training, and

Equipment

Rescue Retrieval Ventilation & Atmospheric Monitoring BarriersAccess/Egress (ladders, etc...)LightingCommunication

Timely Response, Training, and Equipment

Documented training by each team member via simulated rescues in every type of confined space (Rescue training)Authorized Entrant/Attendant First Aid & CPR (Blood-borne pathogens)Haz Com, PPE, Respiratory, Lockout, PSMEquipment training (Fall Protection)

CSR Training:

Each rescue team member must be trained to safely perform all assigned rescue duties.

- Rigging - Entry (claustrophobia)- PPE utilized outside the space- Equipment maintenance- Individual skills (IPE)

Hands-on Rescue Training:

Each member must practice simulated rescue operations at least once every 12 months in the actual PRCS or representative spaces that simulate the types of spaces based on opening size, configuration, and accessibility….

Rescue in Confined Space

What are the requirements for What are the requirements for practice rescue exercises?practice rescue exercises?

1. Practice exercise must involve the actual removal of dummies or persons from the actual permit spaces or from representative spaces.

2. Representative spaces need to simulate the types of permit spaces from which rescues may be performed with respect to:

· Opening size

· Configuration

· Accessibility

Ventilation of Confined Spaces

Confined Space Ventilation

Confined spaces are not normally designed for convenient ventilationMust take steps to: ensure air is breathable before

entering confined space maintain acceptable air quality in the

confined space during entry

Hotwork in Confined Spaces

Presents additional ventilation challenges in confined spacesIncludes torch cutting, welding, brazing and soldering, arch gouging

Hotwork in Confined Spaces

Remember… confined spaces concentrate hazards!Hotwork can create atmospheric hazards in confined spaces from fumes, gasses and vaporsEffective ventilation sometimes may only be accomplished by mechanical ventilation

Natural Ventilation in Confined Spaces

“Chimney Effect” convection process created by

temperature changes

Occurs by sunlight heating vessel walls and air withinIf there is an opening in bottom and top of vessel, upward draft created

Natural Ventilation Problems

Confined spaces rarely experience uniform thermal conditionsVarious sources of heat in confined spaces human bodies lighting hotwork processes

Natural Ventilation Problems

Factors such as sunlight, body heat, lighting and hotwork are usually not sufficient to move enough air to provide an acceptable atmosphere

Use of Mechanical Ventilation

Properly installed, can reduce or eliminate respiratory protection requirementsEffective engineering controls usually less dependent on worker attention than respiratory protection

When is ventilation necessary?

If atmosphere: contains insufficient oxygen or is

oxygen rich contains flammable dusts or vapors contains hazardous or toxic vapors,

mists, fumes, gases, or fibers

When is ventilation necessary?

If atmosphere: is subject to activities that may

generate hazardous mists, vapors, fumes or gases, or may create either an oxygen deficiency or oxygen excess, and

increases heat stress on workers to unacceptable levels

CAUTIONS

Many people resist wearing PPE, including respiratory protectionTangle of supplied air hoses in vessel with many welders can present a hazard

Ventilation- 29 CFR 1910.252(c)

Spaces that require ventilation work space less than 16 feet high volume less than 10,000 cubic feet

per welder work areas with partitions, structural

barriers, or other barriers that significantly obstruct airflow

Ventilation- 29 CFR 1910.252

Ventilation options: provide at least 2000 cfm of airflow

for each active welder; or provide each welder with a local

exhaust device local exhaust devices must be capable of

maintaining a velocity of 100 fpm toward the air intake

Ventilation Requirements

29 CFR 1910.252 and 29 CFR 1926.353 require use of local exhaust ventilation or supplied air respiratory protection when performing hotwork using certain substances

Air Moving Devices

Two types: Fans Venturi-type eductors

Can be air, steam or electrically driven

Eductors

Sometimes called “air horns”Air powered and rely on venturi effects to move air

Criteria for Rating Air Movers

Free Air DeliveryEffective Blower CapacityQuantity of air and air pressure required (air-driven devices)Electrical power requirements (electrically driven devices)

Factors Reducing Performance

Equipment components in confined space Maintenance/construction materials erected in space Obstructions in make-up air manway Insufficient number of make-up air manways

Factors Reducing Performance

More restrictions to overcome = less air moved Air moving into space equals amount of air leaving the space

Air Driven Devices- Poor Performance

Reduced pressure and volume to air driven devices from multiple usersExcessively long air hoses

Increasing Performance

Supplemental air compressors dedicated to air mover use (air driven devices)Supplemental air compressors connected directly to plant air systemEliminate “short-circuiting” of airflow

Designing Ventilation Systems

Configuration, contents and tasks determine type of ventilation opening configuration properties of expected atmospheric

hazards type of work being performed

Electrically Driven Centrifugal Fans

Designed to overcome higher static pressuresUsually heavier than air-driven equipmentCan be used remotely to reduce noiseDue to power, can suck up debris

Local Exhaust

Single manway vesselsInterior obstructions that create “dead spots”Lack of feasible way to attach air-moving deviceWork with toxic metals

Local Exhaust

Effective only when it captures and removes welding fumes and gasses at the source as they are emitted100 fpm capture velocity at the source of fumes or gasses

Local Exhaust- Considerations

Long runs reduce airflowAirflow loss minimized by use of smooth ducting with large radius bendsRun flexible ducting as straight as possibleConsider using plenums for multiple weldersField test flow/personal air monitors

Make-up air quality

Mechanical ventilation uses surrounding airMake sure the make-up air is not a source of airborne contaminants

Confined Spaces

Pre Entry

Consider the following:

Piping systems

Electrical hazards

Illumination

Ventilation

Means of access

Fall protection

Pre Entry

Visual Inspection (Competent Person)Employee TrainingExchanging InformationAtmospheric Testing Shipyard Competent Person Certified Marine Chemist Certified Industrial Hygienist Coast Guard Authorized Person

Rescue Teams

Entry

Atmospheric TestingWarning Signs and LabelsVisual InspectionVentilationPPE for EntryRescue Teams

Work

Hot WorkCleaning