HVACR416 - Design

Confined Spaces

Confined Space Entry Definitions:

The entrant is the person who enters a confined space.

The attendant is the person who stays with the entrantoutside the confined space, and is responsible for assisting the entrant in exiting the confined space, and calling for emergency assistance when required.

The safety representative is the qualified person whoevaluates the hazards, prescribes required equipmentand precautions and issues the Confined Space Entry Permit.

Confined Space Entry Goals and Objectives:

At the end of this session you will:

Be familiar with the hazards and requirementsof “safe” confined space entry.

Pass a 10 question quiz with a score of 100%.

Confined Space Entry - Hazards

Both animal and plant liferequire oxygen to live. One of theprimary hazards of enteringconfined spaces is oxygendeficiency.

When oxygen is present inconcentrations less than 19.5%the atmosphere is said to beoxygen deficient.

O2

O2

Confined Space Entry - Hazards

Oxygen can also be presentin concentrations that aretoo high.

Oxygen in concentrationsgreater than 23% is toooxygen rich and can causecombustible materials to ignite very quickly.

Confined Space Entry - Hazards

Oxygen Deficiency

Can be caused by several processes:

Consumption: oxygen is used up by the person who is in the confined space and turned into carbon dioxide.

Displacement: denser materials push the oxygen out ofthe occupied space.

Reaction: oxygen is reacted with other materialsto make other compounds.

Confined Space Entry - Hazards

The human body requiresoxygen to carry out cellular metabolism. Oxygen is brought in through the lungs and transported to cells ofbody organs by the redblood cells. When blood isrich in oxygen it turns red.

O2

CO2

After oxygen is deliveredto body organs and usedby organ cells, it reactswith carbon to makecarbon dioxide. Redblood cells carryingcarbon dioxide turnblue. Carbon dioxide iscarried back to the lungsby the red blood cellsand exhaled into the surrounding atmosphere.

Confined Space Entry - Hazards

CO2

O2

Given a fixed amount of oxygenas you would have in a confinedspace, respiration of oxygencauses carbon dioxide toincrease. When oxygendecreases to less than 19.5%.the atmosphere is said to be oxygen deficient, putting occupants of the confined space at risk oflosing consciousness and death.

Confined Space Entry - Hazards

Processes which operate by theprinciple of combustion use upoxygen much faster than thehuman respiration.

Products of combustion varywith the fuel that is present andthe temperature of the combustion reaction. Welding, burning natural gas, propane, gasoline, and diesel engines are examples of combustion processes.

CO2

H20

NOxCO

O2

fuel

Confined Space Entry - Hazards

Manholes often remaincovered for long periods of time. Naturally occurring toxins, such as hydrogen sulfidecan accumulate inside of manholes.

H2S

Manholes may alsoaccumulate highlyflammable gassessuch as methaneand ethane. Unlikethe gas we receive athome, we cannot detect some of these gases with our sense of smell.

CH4

Confined Space Entry - Hazards

Toxic and flammablematerials are sometimesillegally put into sanitaryand storm sewers.Leaking tanks or spillsmay migrate underground causing seepageinto manholes.

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Material can leachthrough soil frommany miles away.

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Confined Space Entry - Hazards

Sudden releases offluid solids, such asgranulated salt, sugar, or sand, liquids, and dense gases can cause engulfment of persons inside underground tanks, or pits.

When torrential forcesare suddenly released, people may be struck by moving objects , or be pushed helplessly downstream.

Confined Space Entry - Hazards

Trenches, ravines and other excavations may also be considered confined spaces, if there is a potential for accumulation of toxic gases, engulfment and/or the depletion of oxygen.

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Confined Space Entry - Hazards

Many confined spaceentries involve acomplex set of exposuresto mechanical, electrical,pressure and chemicalhazards.

Confined Space EntryThe entry of a confined space begins with a

Confined Space Entry Permit.

Confined Space Entry Permit

Location and Description of Confined Space:

Reason for Entry:

Permit Issued to (Name of Company/Organization):

The permit system requiresthat a qualified safetyrepresentative visit thework location and evaluatethe conditions under whichentry will be made.

Confined Space Entry

Each process hazard to whichthe entrant may be exposed,adjacent operations or processes,and scheduled activityare reviewed. For each hazardidentified, countermeasuresare detailed on the ConfinedSpace Entry Permit.

Confined Space EntryThe safety representativetests the space for hazardous concentrations of known harmful substances, such as hydrogen sulfide,carbon monoxide, and flammable liquid or gas.The concentrationof oxygen is measuredat the same time.

Confined Space Entry - Hazards

If concentrations ofmaterials are found tobe at harmful levels,the confined spacemust be ventilated toremove them beforeentry.

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Fresh Air

Fresh outsideair is blown intothe space to dilute and remove contaminants,andsupply oxygen.

O2 O2

O2

O2

Confined Space Entry - Hazards

Should the concentrationof contaminants remainat harmful levels,respirators may have tobe worn to assure a safeair supply.

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Fresh Air

O2 O2

O2

O2

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Confined Space EntryMeans of emergency rescue must be readily available to the confined space entry attendant for emergency extrication ofentrants.

Confined Space Entry

A means must be providedfor both safe normal entryor exit , and emergencyextrication. Tripods with hoist,lifeline, and full body harness are often used for emergency extrication. Ladders may be used for ordinary entry and exit.

Confined Space Entry

Barriers to prevent passers-by and the curious from falling into the opening must be put in place.Holes and openings must be closed or guarded when not attended.

Confined Space Entry

Place warning signs where pedestrians can see them.

Signs must state the hazard and the required action.

CAUTIONOpening in

GroundKeep Out !

Confined Space EntryConfined Space Entry Permit

Requirements

Eye protection yes noRespiratory protection yes noContinuous Ventilation yes noBody Protection yes noHand Protection yes noFoot Protection yes noWeather Protection yes no

Required countermeasures include personal protective equipment for hazards expected to be found within the confined space.

Eye and head injuries are always a potential, therefore safety glasses and hard hats are required wear for entrants.

Other conditions may require theuse of respirators, safety shoes,protective gloves, and otherpersonal protective equipment.

o

Danger

Do not use!

Confined Space EntryConfined Space Entry Permit

Requirements

Ground Fault Interruption yes noLockout of HazardousEnergy Sources yes no

Required countermeasures alsoinclude prevention of electricalshock hazards due to loss of earth ground for portable tools.GFCI’s are required for portableelectric tooling.

There may also be a need tolockout and tag equipment bothin the confined space and onadjacent equipment and processes.

Confined Space Entry

H2S

HCN

Entrants must leave theconfined space when themonitor alarm is activated.

It is the attendant’sresponsibility to see that the entrant leaves thespace during an alarm.CH4

CO

CO2

O2

Entrants must constantly monitorthe confined space for toxic gases,oxygen, and combustible gases.Entrants will be issued a personal monitor to wearfor this purpose.

Confined Space Entry

Should conditions developwhich require extrication,and the entrant cannotget out of the confined space on their own,the attendant mustcall for emergencyassistance at once!

Confined Space Entry

The attendant shouldattempt to remove theentrant from the confinedspace using tripods, hoist, and lifelines. Attendants are NOT TO ENTER CONFINED SPACES. Lethal hazards may be present within the confinedspace. Only properly equipped and trained emergency rescuepersonnel may enter confined spaces to make rescues.

Confined Space Entry - SummaryConfined space entry hazards can include:

- the presence of toxic substances- insufficient oxygen, or too much oxygen- engulfment- presence of combustible gases and liquids- process or equipment related hazards.- conditions changing from nonhazardousto hazardous.

Confined Space Entry - Summary

Confined Space Entry Permit

Location and description of confined space:Reason for entry:Permit issued to:Supervisor’s Name:Attendant’s name:Permit issuer’s name:% oxygen: % lower explosive limit: ppm CO: H2S:

Requirements

Emergency Rescuer yes noContinuous Gas Monitor yes noBarrier for ground openings yes noWarning Signs yes noSafety Harness withlife line yes noTripod / Hoist / Pulley yes noAccess (ladders/other) yes noEye protection yes noRespiratory protection yes noContinuous Ventilation yes noBody Protection yes noHand Protection yes noFoot Protection yes noWeather Protection yes noGround Fault CircuitInterrupters yes noLockout of HazardousEnergy yes no

Required countermeasures aredetermined by a qualified safetyprofessional.

Once the required countermeasuresare in place, a permit is issued by the safety representative and the confined space may be safely entered.

Should an emergency arise during the entry, the attendant notifies an emergency response team and attempts to extricate the entrant.

Confined Space Entry -Summary

Confined Space

Safe Work Permit Required

CAUTION

Confined spaces are required to be labeled. Some spacesmay have been overlooked. Contact your safety representative when in doubt.It is up to you to obey signs and to follow permit procedures before entry.

Where to Get Help?

The supervisor of a confined space entry should be contacted for any equipment necessary to complete the task at hand.

Safety Representatives are responsible for answering questions about the confined space entry permit, countermeasures, sampling methods, and instrumentation.

References and Sources

More Information

OSHA 29CFR 1910.146 Permit - Required Confined Spaces