Safety in confined space

Safety in Confined Space by The Apprentiicewww.theapprentiice.com

INTRODUCTION
If you are required to construct or
work in a :
BOILER , CUPOLA , DEGREASER,
FURNACE, PIPELINE,PIT,PUMPING
STATION,REACTION OR PROCESS
VESSEL,SEPTIC TANK,SEWAGE
DIGESTER,SEWER,SILO,STORAGE
TANK,SHIP’S HOLD,UTILITY VAULT
or similar type enclosure,
You are working in a confined space
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How Can you Identify a Confined
Space?
• Limited openings for entry
and exit
• Unfavorable natural
ventilation
• Not designed for continuous
worker occupancy

Limited openings for entry and exit:
• Confined space openings are limited primarily by
size or location.
• Openings are usually small in size , perhaps as
small as 18 inches in diameter, and are difficult to
move through easily.
• In some cases openings may be very large , for
example open-topped spaces may require the
use of ladders, hoists, or other devices, and
escape from such areas may be very difficult in
emergency situations.

Unfavorable natural ventilation:
• No free movement of air
• Deadly gases may be trapped
inside
• Not enough or
• The air could be so oxygen-rich
that it is likely to increase the
chance of fire or explosion if a
source of ignition is present

Not designed for continuous worker
occupancy:
• Most confined spaces are not designed for
workers to enter and work in them on a routine
basis.
• They are designed to store a product, enclose
materials and processes, or transport products or
substances.
• Therefore, occasional worker entry for inspection,
maintenance, repair, clean up, or similar tasks is
often difficult and dangerous due to chemical or
physical hazards within the space.
•

What are the Hazards Involved in
Entering and working in Confined
Spaces

• Oxygen-deficient atmospheres,
• Flammable atmospheres, and / or
• Toxic atmospheres.
Hazards Involved in Entering and working in
Confined Spaces

OXYGEN-DEFICIENT ATMOSPHERES:
Less than 19.5% available oxygen (O2)
The oxygen level in a confined space can decrease
because of
• work being done, such as welding, cutting, or brazing;
or, it can be decreased by certain chemical reactions
(rusting) or through bacterial action (fermentation).
• Oxygen is displaced by another gas, such as carbon
dioxide or nitrogen.
• Total displacement of oxygen by another gas, such as
carbon dioxide, will result in unconsciousness, followed
by death.

FLAMMABLE ATMOSPHERES:
• Two things make an atmosphere flammable:
1) the oxygen in air; and
2)a flammable gas, vapor, or dust in the proper mixture.
• Different gases have different flammable ranges. If a source
of ignition is introduced into a space containing a
flammable atmosphere , an explosion will result.
• An oxygen-enriched atmosphere (above 21%) will cause
flammable materials , such as clothing and hair, to burn
violently when ignited.

TOXIC ATMOSPHERES:
• Most substances should be
considered hazardous in a confined
space. Toxic substances can come
from the following:
– The product stored in the space:
The product can be absorbed into
the walls and give off toxic gases
when removed or when cleaning out
the residue of a stored product, toxic
gases can be given off. Example:

Actions to taken / Preparation before
entering a confined space

TESTING THE ATMOSPHERE

VENTILATION
• Ventilation by a blower or fan may be
necessary to remove harmful gases and
vapors from a confined space.
• Under certain conditions where
flammable gases or vapors have
displaced the oxygen level, but are too
rich to burn, forced air ventilation may
dilute them until they are within the
explosive range.
• If inert gases(e.g. carbon dioxide ,
nitrogen , argon) are used in the
confined space, the space should be well
ventilated and re-tested before a worker
may enter. www.theapprentiice.com

ISOLATION
Isolation of a confined space is a process
where the space is removed from service
by:
• Locking out - Electrical sources , preferably
at disconnect switches remote from the
equipment.
• Blanking and bleeding- Pneumatic and
hydraulic lines
• Disconnecting - Belt and chain drives ,
and mechanical linkages on shaft – driven
equipment where possible and
• Securing Mechanical moving parts within
confined spaces with latches , chains,
blocks

RESPIRATORS
• Respirators are devices that can allow workers to
safely breathe without inhaling toxic gases or
particles. Two basic types are air-purifying, which
filter dangerous substances from the air, and air-
supplying, which deliver a supply of safe breathing
air from a tank or an uncontaminated area nearby.
• ONLY AIR- SUPPLYING RESPIRATORS SHOULD BE
USED IN CONFINED SPACES WHERE THERE IS NOT
ENOUGH OXYGEN.
• Selecting the proper respirator for the job, the
hazard, and the person is very important , as is
thorough training in the use and limitations of
respirators.

STANDBY/RESCUE
• A standby person should be assigned to remain on the outside
of the confined space and be in constant contact (visual or
speech) with the workers inside.
• Over 50% of the workers who die in confined spaces are
attempting to rescue other workers. Rescuers must be trained
in and follow established emergency procedures and use
appropriate equipment and techniques
• Rescue should be well planned and drills should be frequently
conducted on emergency procedures.
• Unplanned rescue, such as when someone instinctively rushes
in to help a downed co-worker, can easily result in a double
fatality, or even multiple fatalities if there are more than one
would – be rescuers.

GENERAL / PHYSICAL HAZARDS
• TEMPERATURE EXTREMES:
Extremely hot or cold temperatures can present
problems for workers. For example , if the space
has been steamed , it should be allowed to cool
before any entry is made.
• ENGULFMENT HAZARDS:
Lose , granular material stored in bins and
hoppers , such as grain , sand, coal or similar
material , can engulf and suffocate a worker. The
loose material can crust or bridge over in a bin
and break loose under the weight of a worker.

GENERAL / PHYSICAL HAZARDS
• NOISE:
Noise within a confined space can be amplified because of the
design and acoustic properties of the space. Excessive noise can not
only damage hearing, but can also affect communication, such as
causing a shouted warning to go unheard.
• SLICK/WET SURFACES:
Slips and falls can occur on a wet surface causing injury or death to
workers. Also , a wet surface will increase the likelihood for and
effect of electric shock in areas where electrical circuits, equipment ,
and tools are used.
• FALLING OBJECTS :
Workers in confined spaces should be mindful of the possibility of
falling objects, particularly in spaces which have topside openings
for entry , and where work is being done above the worker.www.theapprentiice.com

CHECKLIST TO EVALUATE THE
CONFINED SPACE

TESTING
• Are the instruments used in atmospheric testing properly
calibrated?
• Was the atmosphere in the confined space tested?
• Was oxygen at least 19.5% - not more than 21%?
• Were toxic , flammable, or oxygen – displacing gases / vapors
present?
• Hydrogen Sulfide
• Carbon Monoxide
• Methane
• Carbon Dioxide
• Other (list) )______

MONITORING
• Will the atmosphere in the space be monitored while
work is going on?
– Continuously ?
– Periodically? (If yes , give
interval:________________________)
• REMEMBER – ATMOSPHERIC CHANGES OCCUR DUE
TO THE WORK
• PROCEDURE OR THE PRODUCT STORED.THE
ATMOSPHERE MAY BE SAFE
• WHEN YOU ENTER, BUT CAN CHANGE VERY QUICKLY.

CLEANING
• Has the space been cleaned before
entry is made?
• Was the space steamed?
• If so , was it allowed to cool?

VENTILATION
• Has the space been ventilated before entry?
• Will ventilation be continued during entry?
• Is the air intake for the ventilation system
located in an area that is free of combustible
dusts and vapors and toxic substances?
• If atmosphere was found unacceptable and
then ventilated, was it re-tested before
entry?

ISOLATION
• Has the space been isolated from other systems?
• Has electrical equipment been locked out?
• Have disconnects been used where possible?
• Has mechanical equipment been blocked , chocked, and
disengaged where necessary?
• Have lines under pressure been blanked and bled ?

CLOTHING / EQUIPMENT
• Is special clothing required (boots, chemical suits, glasses, etc.)?
(If so , specify : ______________________________________)
• Is special equipment required (e.g.. rescue equipment,
communications equipment ,etc.)?
(If so , specify :_________________________________)
• Are special tools required (e.g., sparkproof)?
(If so , specify :_______________________________)

RESPIRATORY PROTECTION
• Are approved respirators of the type required available at the
worksite?
• Is respiratory protection required (e.g., air – purifying
,supplied air, self – contained breathing apparatus etc.)?
• (If so , specify type :
_______________________________________)
• Can you get through the opening with a respirator on ? (If you
don’t know , find out before you try to enter.)www.theapprentiice.com

TRAINING
• Have you been trained in proper use of a
respirator?
• Have you received first aid / CPR training ?
• Have you been trained in confined space entry and
do you know what to look for?

STANDBY/ RESCUE
• Will there be a standby person on the outside in constant visual or auditory
communication with the person on the inside?
• Will the standby person be able to see and / or hear the person inside at all times?
• Has the standby person(s) been trained in rescue procedures?
• Will safety lines and harness be required to remove a person?
• Are company rescue procedures available to be followed in the event of an
emergency?
• Are you familiar with emergency rescue procedures?
• Do you know who to notify and how in the event of an emergency?www.theapprentiice.com

WORK PERMIT
The work permit is an authorization in writing that states
that the space has been tested by a qualified person, that
the space is safe for entry ; what precautions, equipment ,
etc. are required; and what work is to be done.
• Has a confined space entry permit been issued?
• Does the permit include a list of emergency telephone
numbers?

Summary
• What is a confined space?
• Hazards of entering and working in Confined
Spaces
• Actions to taken / Preparation before entering
a confined space
• Checklist prior to commencing work in a
confined space

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Safety in confined space

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