YES NO
([J [2] Can you get through the opening with a respirator

on? (If you don’t know, find out before you try to
enter.)

TRAINING
(7) (5) Harve you been trained in proper use of a respirator?
CJ (2) Fave you received first aid/CPR training?

CI [] 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?

CJ ([) Wilt the standby person be able to see and/or hear the
person inside at all times?

C1 (() Has the standby person(s) been trained in rescue
procedures?

(J (2D Wil safety lines and harness be required to remove a
person?

(7 LC Are company rescue procedures available to be
followed in the event of an emergency?

() (1) Are you familiar with emergency rescue procedures?

[1 CL) Do you know who to notify and how in the event of an
emergency?


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. The standby
person should not have any other duties but to serve as
standby and know who should be notified in case of emergency.
Standby personnel should not enter a confined space until

help arrives, and then only with proper protective

equipment, life lines, and respirators.

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
(lifelines, respiratory
protection, standby
persons, etc.). Steps
for safe rescue should
be included in all
confined space entry
procedures. 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 Entry with Hoist and
there are more than one Standby Personnel
would-be rescuers.

REMEMBER: AN UNPLANNED RESCUE WILL
PROBABLY BE YOUR LAST .

~12-


iy @D

Storage Tank

Examples of
Confined Spaces



CIC
CoO

(The 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?

For further information on confined spaces, occupational hazards,
safe work practices, and other topics which could affect your
wellbeing, write to:

PUBLICATIONS DISSEMINATION
National Institute for Occupational
Safety and Health

Robert A. Taft Laboratories

4676 Columbia Parkway
Cincinnati, OH 45226

-19-


YES NO
Mi RIN

(J (J Will the atmosphere in the space be monitored while
work is going on?

C7) (2 Continuousty?

[7] (1 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.

C) (Kas the space been cleaned before entry is made?

C7) (Was the space steamed?

CJ [2] If so, was it allowed to cool?
VENTILATION

(-) (Aas the space been ventilated before entry?

(7) (JWill ventilation be continued during entry?

(J CJIs 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?

16-


VENTILATION

Ventilation by a blower or fan may be necessary to remove
harmful gases and vapors from a confined space. There are
several methods for ventilating a confined space. The method
and equipment chosen are dependent upon the size of the
confined space openings, the gases to be exhausted (e.g., are
they flammable?), and the source of makeup air.

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. Also, 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.

A common method of ventilation requires a large hose, one end
attached to a fan and the other lowered into a manhole or
opening. For example, a manhole would have the ventilating
hose run to the bottom to blow out all harmful gases and
vapors (see diagram). The air intake should be placed in an
area that will draw in fresh air only. Ventilation should be
continuous where possible, because in many confined spaces
the hazardous atmosphere will form again when the flow of air
is stopped.

Ventilating with Fan and Trunk Hose


2. 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 (e.g., a sparking or electrical tool) 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. Therefore, never use pure oxygen to ventilate a confined
space. Ventilate with normal air.

AIR

FLAMUBLE ATHOSPHER

N

Gas, Vapor,

or bust Source of

Ignition

The Ignition Triangle

-5-


What are the Hazards Involved in Entering and Working in

Confined Spaces?

Hazardous Atmospheres

As mentioned, the atmosphere in a confined space may be
extremely hazardous because of the lack of natural air
movement. This characteristic of confined spaces can result in
1) oxygen-deficient atmospheres, 2) flammable atmospheres,

and/or 3) toxic atmospheres.

1. OXYGEN-DEFICIENT ATMOSPHERES:

An oxygen-deficient atmosphere
has less than 19.5% available
oxygen (Oy). Any atmosphere
with less than 19.5% oxygen
should not be entered without
an approved self-contained
breathing apparatus (SCBA).

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).

The oxygen level is also
decreased if 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.

-4-

AN oO, Enriched
21% ——_______
19.5% Minimum fer
Sate Entry
16% —— impaired Judgement
—+ & Breathing

14% —— Faulty Jedg
Rapid Fatigue

at

6% —— Difficult Breathing
Death in Minutes

Oxygen Scale


TION
| Co Has the space been isolated from other systems?
C7] ) Has electrical equipment been locked out?
(J C2) Have disconnects been used where possible?

CT) CL) Has mechanical equipment been blocked, chocked,
and disengaged where necessary?

[J] (2) Have lines under pressure been blanked and bled?
CLOTHING/E: [PMENT

(J (21 Is special clothing required (boots, chemical suits,
glasses, etc.)?

(If so, specify: )

C1) (1) Is special equipment required (e.g., rescue equipment,
communications equipment, etc.)?

(If so, specify:

C () Are special tools required (e.g., sparkproof)?

Cf so, specify: )

RESPIRATORY PROTECTION

[J () Are MSHA/NIOSH -approved respirators of the
type required available at the worksite?

(7) © 3s respiratory protection required (e.g., air-purifying,
supplied air, self-contained breathing apparatus,
ete.)?

Cf so, specify type: )

-17-


TESTING THE ATMOSPHERE

It is important to understand that some gases or vapors are
heavier than air and will settle to the bottom of a confined
space. Also, some gases are lighter than air and will be
found around the top of the confined space. Therefore, it is
necessary to test all areas (top, middle, bottom) of a
confined space with properly calibrated testing instruments
to determine what gases are present. If testing reveals
oxygen-deficiency, or the presence of toxic gases or vapors,
the space must be ventilated and re-tested before workers
enter. If ventilation is not possible and entry is necessary
(for emergency rescue, for example), workers must have
appropriate respiratory protection.

NEVER TRUST YOUR SENSES TO DETERMINE
IF THE AIR IN A CONFINED SPACE IS

SAFE! YOU CAN NOT SEE OR SMELL MANY
TOXIC GASES AND VAPORS, NOR CAN YOU
DETERMINE THE LEVEL OF OXYGEN
PRESENT.

piatyt

Methane
(lighter than air)

Carbon Menexide
(same as air)

Hydrogen Salfide
(oeavier than air)

pheytyt

From the Outside, Top te Scttem

-7-


A Guide to Safety
in Confined Spaces

by

Ted Pettit and Herb Linn

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
Public Health Service

Centers for Disease Control

National Institute for Occupational Safety and Health

July 1987

For sale by the Superintendent of Documents, Congreasional Sales Office
US. Government Printing Office, Washington, DC 20402


donoh

Method of Blanking Hydraulic/Poeumatic Lines

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. Questions

regarding the proper selection and use of respirators

should be addressed to a certified industrial hygienist, or

to the NIOSH Division of Safety Resarch, 944 Chestnut Ridge
Rd., Morgantown, West Virginia 26505.

-10-


ISOLATION

Isolation of a confined space is a process where the space is
removed from service by:

- locking out
electrical sources, preferrably 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, chocks, blocks,
or other devices.

“@) (HH

. DINGER
DO NOT
= OPERATE

Examples of Lockout


3. TOXIC ATMOSPHERES:

Most substances (liquids, vapors, gases, mists, solid
materials, and dusts) 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: Removal

of sludge from a tank -
decomposed material can
give off deadly hydrogen

sulfide gas.

The work being performed

in a confined space:

Examples of such include

welding, cutting, brazing,
painting, scraping,
sanding, degreasing, etc.
Toxic atmospheres are
generated in various
Processes. For example,
cleaning solvents are
used in many industries
for cleaning/degreasing.
The vapors from these
solvents are very toxic
in a confined space.

- Areas adjacent to the confined space:

Toxicants produced by work in the area of confined spaces can
enter and accumulate in confined spaces.

-6-


Lack of hazard awareness and unplanned rescue attempts
led to the following deaths:

On July 23, 1985, a city worker was removing an inspection plate
from a sewer line in a 50-foot deep pump station, when the plate
blew off allowing raw sewage to enter the room. Two fellow
workers and a policeman attempted to rescue the worker from the
sludge filled room and were unsuccessful. All four were dead
when removed from the pumping station.

On February 21, 1986, a self-employed truck driver died after
entering the top of a 22-foot high x 15-foot square sawdust bin.
He suffocated when the sawdust inside the bin collapsed and
buried him.

On July 5, 1986, a worker entered a chemical degreaser tank to
clean out the bottom and collapsed. Two fellow workers noticed
the man down and went in to rescue him. All three workers died.

On July 16, 1986, a worker entered a septic tank to clean out the
residue at the bottom and collapsed shortly afterward. Two
workers on the outside went in to rescue the downed worker. All
three were dead when removed from the tank.

On October 10, 1986, a self-employed plumbing contractor entered
an underground water line vault to inspect a backflow device. The
contractor collapsed shortly after entering the vault. A supervisor
noticed the man down, and entered the vault in a rescue attempt.
Both men had entered an untested oxygen -deficient atmosphere,
and died as a result.

On February 6, 1987, two workers (father and son) at a wastewater
plant were working on a digester that was being drained. They
went on top of the digester and opened a hatch to check the sludge
level. To provide light in the digester, they lowered an extension
cord with an exposed 200 watt light bulb into the digester. The
light broke and caused the methane gas in the digester to explode,
killing both men instantly.

If the guidelines in this pamphlet had been followed, these fatalities
would have been prevented.

-20-


Unfavorable natural ventilation:

Because air may not move in and out of confined spaces freely
due to the design, the atmosphere inside a confined space can

be very different from the atmosphere outside. Deadly gases
may be trapped inside, particularly if the space is used to

store or process chemicals or organic substances which may
decompose. There may not be enough oxygen inside the confined
space to support life, 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, cleanup, or similar tasks is

often difficult and dangerous due to chemical or physical hazards
within the space.

A confined space found in the workplace may have a combination
of these three characteristics, which can complicate working in
and around these spaces as well as rescue operations during
emergencies. If a survey of your working area identifies one

or more work spaces with the characteristics listed above,

READ THE FOLLOWING INFORMATION - SOMEDAY IT MAY
SAVE YOUR LIFE, OR THE LIFE OF A CO-WORKER.

~2-


GENERAL/PHYSICAL HAZARDS

In addition to the areas discussed above, evaluation of a
confined space should consider the following potential

hazards:
1, 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.

2. ENGULFMENT HAZARDS:

Loose, 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.

ie
\s

1 2 °3

The Hazard of Engulfment in Unstable Material

-13-



RECOMMENDATIONS FOR SAFE ENTRY: A CHECKLIST
Use the following checklist to evaluate the confined space.
DO NOT ENTER A CONFINED SPACE UNTIL YOU

HAVE CONSIDERED EVERY QUESTION, AND HAVE
DETERMINED THE SPACE TO BE SAFE.

YES NO

©) (J 5s entry necessary?
TESTING

| [JAre the instruments used in atmospheric testing
properly calibrated?

() L JW as the atmosphere in the confined space tested?
(J C JWas Oxygen at least 19.5% - not more than 21%?

oO (JWere toxic, flammable, or oxygen-displacing
gases/vapors present?

-Hydrogen Sulfide
- Carbon Monoxide
- Methane

- Carbon Dioxide

~ Other (list)

-15-


INTRODUCTION

If you are required to construct or work in 2

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, VAT, or similar type enclosure,

you are working in a confined space (See examples on page 3).
How Can You Identify a Confined Space?

A confined space is a space which has any one of the following
characteristics:

« limited openings for entry and exit
e unfavorable natural ventilation

e 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. Small openings may make it very difficult to get
needed equipment in or out of the spaces, especially protective
equipment such as respirators needed for entry into spaces with
hazardous atmospheres, or life-saving equipment when rescue is
needed. However, in some cases openings may be very large, for
example open-topped spaces such as pits, degreasers,
excavations, and ships’ holds. Access to 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.


What is NIOSH?

The National Institute for Occupational Safety and Health
(NIOSH) was formed in 1971 to conduct research, develop
educational and training resources, and develop criteria for
recommended standards in the area of occupational safety and
health. NIOSH is part of the Centers for Disease Control
(CDC), and the Public Health Service under the Department of
Health and Human Services in the executive branch of the U.S.
Federal Government.

NIOSH employs about 850 administrators, scientists, engineers,
technicians, and support staff at its headquarters in Atlanta,
Georgia, and its laboratories and offices in Cincinnati, Ohio
and Morgantown, West Virginia.

This guide was developed by the NIOSH Division of Safety
Research in Morgantown, West Virginia.

DHHS (NIOSH) PUBLICATION NO. 87-113


Air-Purifying Respirators
(Do Not Use in Oxygen-Deficient Atmosphere)

Half-mask Full-Facepiece

Air-Supplying Respirators

Supplied Air Respirator with Self-contained Breathing
Auxiliary, Escape-only SCBA Apparatus (SCBA)


3. 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.

4. 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.

5. 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.

-14-