Confined Space Entry

Confined Space

(1) Large enough for an employee to bodily enter and perform work AND(2) Has limited or restricted entry or exit AND(3) Is not designed for continuous employee occupancy

Permit Required Confined Space

A confined space that:(1) contains or has a potential to contain a hazardous atmosphere OR(2) has the potential for engulfment OR(3) Has an internal configuration that could trap or asphyxiate OR(4) Contains any other recognized serious safety or health hazard

Confined Space Question…

• Why are we entering this space?

Limited Or Restricted Entry• Any space where an occupant

o Must crawl, climb, twisto Be constrained in a narrow openingo Follow a lengthy patho Exert unusual effort to enter or leaveo May become trapped

Entrance may become sealed or secured against opening from inside

Confined Spaces

Hazardous Atmosphere

• Potential exposure too Risk of deatho Incapacitationo Impairment of ability to self-rescue o Injuryo Acute illness

• If none of the aboveoDoes not apply to this standard

Reclassify• Reclassify to a non-permit space if

o All potential for a hazardous atmosphere is eliminated AND

o All other hazards and potential hazards are eliminated/controlled

Air & Oxygen• Air and oxygen are NOT synonymous.• Air contains

o 20.9% oxygeno 78.1% nitrogeno 1% argono Trace amounts of other gases

Hazardous Atmosphere

• Flammable gas, vapor, or mist in excess of 10 percent of its lower flammable limit (LFL)

• Airborne combustible dust at a concentration that meets or exceeds its LFLo Or visibility 5’ or less

Hazardous Atmosphere

• Atmospheric oxygen concentration below 19.5 percent or above 23.5 percent

• Atmospheric concentration of any toxic substance for which a dose or a permissible exposure limit is published

• Any other atmospheric condition that is IMMEDIATELY DANGEROUS TO LIFE OR HEALTH. (IDLH)

Delayed Threat• Cadmium vapor and hydrogen fluoride

oMay seem ok; immediate symptoms go away

oFatal 12 to 72 hours later

Conditions That Can Cause Oxygen Deficiency

• Adsorption by porous surfaceso Activated charcoal

• Consumed by chemical reactionso Rustingo Fermentation

• Displacedo Inert gasses

Argon CO2 Nitrogen

Conditions That Can Cause Oxygen Enrichment

• Poorly designed or malfunctioning O2 storage or dispensing equipment

• Leaks from oxy-acetylene welding or cutting equipmento Couplings, fittings hoses

• Ventilating with pure oxygen

Flammable Atmospheres• Vapor burns, not liquid• Flammability based on

o Amount of vaporo Temperature

Tank Residue• Explosions often caused by residue in

“empty” tanks or spaces

Residue In Tanks 99% EmptyTANK SIZE (GALLONS)

50,00040,00030,00020,00010,0005,0002,5001,000

RESIDUE (GALLONS)500400300200100502510

Upper & Lower Flammable Limits

AIR100% 0%

GAS0% 100%

LEAN RICHEXPLOSIVE

RANGE

LEL UEL

Flammable Atmosphere: Propane

Flammable Atmospheres

Ignition Sources• Open flame• Electrical arcing• Hot surfaces

o Light bulbs• Static electricity• Frictional sparks• Chemical reactions

230o C

Control Of Ignition Sources• Non-sparking tools• Approved electrical equipment• Purged & pressurized equipment• Intrinsically safe equipment• Explosion proof equipment• Vessel inerting

Control Of Ignition Sources: Hot Work Precautions

• Hot work permits• Welding & cutting precautions

o Control of torches & control valveso Hoses & regulators

In good condition Inspected Minimal tape

o Fire prevention & protection

Toxic Atmospheres

TOXIC:

• Harmful, destructive• Deadly• Poisonous

(THE AMERICAN HERITAGE DICTIONARY)

Sources of Toxic Atmospheres• Products stored in space• Work being performed in space

o Painting, cleaning & degreasingo Welding, cutting & brazing

• Adjacent areas oToxins enter & accumulateoLeaching oChemicals dumped into sewers,

streams

Toxic Gasses• Irritant Gas

o Serious effects may be delayedo Examples

Ammonia, chlorine, sulfur dioxide, ozone, nitrogen dioxide

• Asphyxiate Gaso Smothers due to lack of oxygeno Two classes

Simple asphyxiates Chemical asphyxiates

Simple AsphyxiatesDisplaces oxygen:• Acetylene• Argon• Ethane• Ethylene• Helium

• Hydrogen• LP gas• Methane• Neon• Nitrogen

Chemical AsphyxiatesCause asphyxiation through biochemical reaction• Hydrogen sulfide• Carbon monoxide• Hydrogen cyanide

Engulfment

"The surrounding and effective capture of a person" by• A liquid

• Finely divided (flowable) solid

OR

Engulfment• Quicksand effect• Material drawn from bottom• Bridges created by air pockets

Air Pocket

Mechanical Hazards• Manually isolate each piece of

equipmento Prevent vapor leaks, flashbacks, etc.

• All pipes must be physically disconnected or isolation blanks bolted in placeo Closing valves not sufficiento Inspect & test for leakage

• Also consider steam valves, pressure lines, chemical transfer pipes

Lockout - Tagout• Render ALL hazardous equipment

related to space inoperableo Including accidental startup by others

Refer to Lockout/Tagout Standard: 1910.147

Control, Isolation Methods

• Lockout/tagout • Purging• Block & bleed• Inerting• Ventilating• Flushing

Noise• Noise usually intensified in spaces

o Exposure may be higher than in open environment

• May disrupt verbal communicationo Especially with attendant

Air Testing Instruments• Many different kinds of instruments• Results not instantaneous

o Delay for portable instruments 30-60 seconds

• Assure properly calibrated• Proper care & maintenance

o Per manufacturer

Air Testing Instruments

• Understand use & limitationso Accuracy may be +/- 2%, 5%…o May be affected by extremes of

temperatureo May be affected by rich CO2 atmosphereo May only operate properly within certain

temperatures and relative humidity

Air Testing• Test in order

o Oxygeno Flammableso Toxins

• Test at various levels• Test various places• Continuously monitor• Test around cover before opening

Air Testing

Alarm Devices• ”Alarm only" devices which do not

provide readings are not acceptable o For initial (pre‑entry) or o Periodic (assurance) testing

• Not enough information to establish acceptable entry conditions

• Combination units may be acceptable o Benefit of automatic alarming at

predetermined value.

Ventilation Equipment• Wide variety of types of ventilation

equipmento Size & portabilityo Air volume capabilitieso Power sources

Ventilation Only EntryRequired• Demonstrate: only hazard is actual or

potential hazardous atmosphere• Demonstrate: continuous forced air

ventilation alone is sufficient to maintain safe entry

• Develop monitoring and inspection data to support these demonstrations

Hazard Control Hierarchy• Eliminate hazard

o Engineering controlso Process modification

• Substitute less hazardouso Materialso Methodso Techniques

• Personal protective equipment

Personal Protective Equipment• Proper fit• Cleaning & maintenance• Replacement• Proper use• Will not interfere with movement within

space• Employee training

Respiratory Protection• Vast selection

o Types, styleso Limitationso Specific uses

• Have selection made by qualified person

Permit-required SpacesGeneral Requirements• Evaluate:• Identify all confined spaces• Evaluate to determine if any spaces are

permit required confined spaces.

Permit-required SpacesGeneral Requirements

• Notify employees ofo Existenceo Location ando Danger

• Post signs

There, and there, and over there...

Permit-required SpacesGeneral Requirements

• If employees will enter permit spaces:o Develop & implement a written permit space

program

Written Program

• Ensure that EVERY confined space iso Evaluated as a possible permit spaceo Reevaluated when its uses or surroundings

change.

Entry

“IS CONSIDERED TO HAVE OCCURRED AS SOON AS ANY PART OF THE ENTRANT'S BODY BREAKS THE PLANE OF AN OPENING INTO THE SPACE”

Permit Required Confined Space Entry Team

• Entrant• Attendant• Entry supervisor• Rescuers

Rescuers• 60% OF CONFINED SPACE VICTIMS

ARE WOULD BE RESCUERS (NIOSH STUDY)

Dial 911 - ?• Must be informed of hazards• Must have access to all permit spaces• Must be trained• Should be available

o Make arrangements BEFORE need arises

Non-entry Rescue• Use non-entry rescue whenever

possible• Use retrieval systems or methods

whenever an entrant enters a permit spaceo Unless the retrieval equipment would

increase the overall risk of entry or would not contribute to the rescue of the entrant

Non-entry Rescue• A mechanical device

must be available for rescue for vertical type permit spaces more than 5 feet deep.

Entry Permit

• Actual document• Contains specific required information

about entry• Provides history of entry• Retain for at least 1 year Enter

space #12

QUESTIONS

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SANDRA A. MIHALIKSafety & Health SpecialistMontana Safety & Health

Bureau406.444.6418

e-mail: smihalik@mt.gov