New England
Roofing Industry
Partnership
Confined Space
Controlling Associated Hazards
SUBPART
C
Confined Space
Training Objectives
 After
completing this unit, you will:
– Be aware of the potential dangers of
confined & enclosed spaces that roofers
may encounter.
– Be able to recognize potential hazards in
these work areas.
– Understand that you will need special
training and equipment before working in
an area that meets the characteristics of a
confined space.
1
SUBPART
C
Confined Space
References
 Construction
Industry- 29 CFR
1926.21 (b)(6)(i) & (ii); Subpart C
 General Industry- 29 CFR 1910.146
2
SUBPART
C
Confined Space
Construction vs. General Industry

OSHA Construction Standards apply when
a contractor is building a new confined
space or reconfiguring an old space

If existing confined space, and performing
relining, repainting, cleaning, etc., then
General Industry (1910.146 - Permit
Required) regulations apply.

Host employer (owner) should have permit
required confined space program.
3
SUBPART
C
Confined Space
Typical Confined Spaces
 Vent
Gas Stack, Boiler, Furnace
 Pipeline, Pit, Pumping Station
 Reaction or Process Vessel, Mills
 Septic Tank, Sewage Digester
 Silo, Storage Tank, Barge
 Sewer, Utility Vault, Manhole
 Trenches, Shafts, Caissons
4
SUBPART
C
Confined Space
How to Identify
Confined Spaces
 Limited
Openings for Entry and Exit
 Unfavorable
 Not
Natural Ventilation
Designed for Worker Occupancy
5
SUBPART
C
Confined Space
Potentially Hazardous
Roofing “Spaces”

Some roofing work spaces may meet several of
the hazardous characteristics, but not be defined
as Confined Spaces:
– Bottoms of drainage pits and other areas where you
may be applying waterproofing coatings
– In corners against walls
– Crawl spaces
– Under and around tanks and AC units
– Any place where you are cramped, and generating
solvent vapors and there is little or no air movement!
6
SUBPART
C
Confined Space
Limited Openings for Entry/Exit
 Openings
can often be as small as 18
inches in diameter.
 Difficult to enter with Self Containing
Breathing Apparatus (SCBA) or other
life-saving equipment.
 Difficult to remove downed worker.
 Exit from large openings may be
difficult due to presence of ladders,
hoists, etc.
7
SUBPART
C
Confined Space
Unfavorable Natural Ventilation
 Lack
of air movement can create an
atmosphere much different than the
outside atmosphere.
 Deadly gases can be trapped inside.
 May not be enough oxygen due to
presence of other gases or chemical
reactions such as rusting.
8
SUBPART
C
Confined Space
Not Designed for Worker
Occupancy
 Most
confined spaces are not designed
to enter and work inside on a regular
basis.
 They are designed:
– To store a product.
– To enclose processes.
– To transport products or substances.
– For occasional worker entry for inspection,
repair, cleanup, and maintenance.
9
SUBPART
C
Confined Space
Hazards of Confined Spaces
 Not
enough Oxygen
 Too much Oxygen
 Flammable Atmospheres
 Toxic Atmospheres
 Temperature Extremes
 Engulfment, Mechanical, Electrical
 Noise, Slick/Wet Surfaces, Falling
Objects
10
SUBPART
C
Confined Space
Not Enough Oxygen
19.5 %
15 - 19%
12-14%
10-12%
8-10%
6-8%
4-6%
Minimum acceptable oxygen level.
Decreased ability to work strenuously.
Impaired coordination. Early symptoms.
Respiration increases. Poor judgment.
Respiration increases. Lips blue.
Mental failure. Fainting. Nausea
Unconsciousness. Vomiting.
8 minutes - fatal, 6 minutes - 50% fatal
4- 5 minutes - possible recovery.
Coma in 40 seconds. Death.
11
SUBPART
C
Confined Space
Too Much Oxygen
 When
Oxygen level is above 23.5%:
– Flammable & combustible materials
burn violently when ignited.
– This could mean hair, clothing,
materials, and just about anything.
 Never
use pure oxygen to ventilate.
 Never store or place compressed gas
tanks in a confined space.
12
SUBPART
C
Confined Space
Flammable Atmospheres
 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.
– Explosive mixtures occur between the
Lower Explosive Limit (LEL) & the Upper
Explosive Limit (UEL)
 Typical
Ignition Sources:
– Sparking or electric tool; Welding/Cutting
– Smoking
13
SUBPART
C
Confined Space
Toxic Atmospheres Can Form
 Due
to product stored in a confined
space:
–Gases released when cleaning.
–Materials absorbed into walls of
confined space.
–Decomposition of materials in the
confined space.
 Due
to work being done:
–Welding, cutting, brazing, soldering.
–Painting, scraping, sanding, degreasing.
–Sealing, bonding, melting.
14
SUBPART
C
Confined Space
Acceptable Safe Atmospheres
 Oxygen:
19.5% - 23.5%
 Explosive
gases and vapors less
than 10% of the LEL.
 Toxic
gases and vapors less than
OSHA’s permissible exposure limits.
15
SUBPART
C
Confined Space
16
Hydrogen Sulfide Gas
Decomposition of materials. Human waste.
 Rotten egg odor at low concentrations.
 Possibly no warning at high concentrations.

PPM
10 ppm
50 - 100
200 - 300
500 -700
>1000
Effect
Permissible Exposure Level
Mild Irritation - eyes, throat
Significant Irritation
Unconsciousness, Death
Unconsciousness, Death
Time
8 Hours
1 Hour
1 Hour
1/2 - 1 Hour
Minutes
SUBPART
C
Confined Space
17
Carbon Monoxide
 Odorless,
colorless gas.
 Combustion by-product.
 Quickly collapse at high concentrations.
PPM
50 ppm
200
600
1000-2000
2000-2500
Effect
Permissible Exposure Level
Slight Headache, discomfort
Significant Irritation
Confusion, nausea, stagger
Unconsciousness
Time
8 Hrs.
3 Hrs.
1 Hr.
2 Hrs.
30min.
SUBPART
C
Confined Space
What Makes This A Confined Space?
18
SUBPART
C
Confined Space
19
Causes of Confined Space Accidents
– Bringing a known hazard into the space.
– Failing to test, monitor & ventilate spaces.
– Entering spaces without a permit program.
– Failure to block, blind, bleed or isolate energy
sources.
– Failure to guard live electrical parts.
– Failure to implement Lock-out/Tag-out.
– Entry by unqualified & untrained personnel.
SUBPART
C
Confined Space
Who is Responsible?
 Contractor
doing work.
 Owner
of the space (the building
owner).
 Shared
responsibility.
20
SUBPART
C
Confined Space
Shared Responsibility
Construction Construction Contractor:
Must comply with Construction
Standards & General Duty Clause.
Existing
Building Owner:
(Modify Space)
Must inform contractor of hazards,
precautions.
Must answer contractor’s questions.
Must discuss entry with contractor.
May require use of company entry
program.
Contractor must train you in Owner
program.
Contractor is responsible for safety.
21
SUBPART
C
Confined Space
22
Permit-Required vs. Non-PermitRequired Confined Spaces
 Permit-Required: Space meets definitions,
multiple hazards are present, work is not
construction and/or Owner requires compliance
with 1910.146 Standard.
 Non
Permit-Required: Space meets
definitions, but only atmospheric hazards are
present and are controllable by ventilation and
continuous monitoring is conducted.
SUBPART
C
Confined Space
Construction Regulations

Construction - 1926.21(b)(6)(I): Requires
instructions to employees who enter
confined spaces.

Construction - 1926.21(b)(6)(ii): Defines the
confined and enclosed spaces which require
instruction.

Construction - 1926.352(g): Requires fire
prevention measures when using fuel gas
and oxygen in enclosed spaces.
23
SUBPART
C
Confined Space
Construction Regulations

Construction - 1926.353(b)(1): Requires
exhaust ventilation when welding, cutting,
or heating is performed in confined
spaces.

Construction - 1926.353(b)(2): Requires
air line respirators and standby person
whenever the means of access is blocked
by ventilation equipment.
24
SUBPART
C
Confined Space
Case Study: What went wrong?
A worker sitting in a
looped chain was
lowered approximately
17 feet into a 21-foot
deep vessel. Twenty
seconds later he started
gasping for air and fell
from the chain seat face
down into the
accumulated water at the
bottom of the manhole.
An autopsy determined
oxygen deficiency as the
cause of death.
25
SUBPART
C
Confined Space
26
Review Questions
 True
or False?
1. The most common type of hazard is
atmospheric.
2. A confined space has limited openings for
entry and exit, unfavorable natural
ventilation, and is not designed for worker
occupancy.
3. Oxygen at levels of 19.5% - 23.5%, and
explosive gases and vapors less that 50% of
the LEL, are acceptable atmospheres to
enter.
4. You can’t have too much oxygen in a
confined space.
SUBPART
C
Confined Space
Review Questions
 True
or False?
5. Using a flammable solvent and a drop light
in a confined space may lead to a potential
explosion.
6. OSHA requires training for confined space
entry.
7. OSHA does not require exhaust ventilation
when welding, cutting, or heating is
performed in confined spaces.
8. Monitoring the atmosphere before a worker
enters and while they are inside is
necessary to ensure a safe entry.
27
SUBPART
C
Confined Space
Review Questions
 True
or False?
9. Workers outside the space should never
enter the space to rescue a fellow worker.
10. Before a space can be entered, all
mechanical hazards and pipes which feed
into the space must be locked and tagged
out in a zero energy state.
28