9. What is a Confined Space?
A space that:
Is large enough and so
configured that an
employee can enter
bodily and perform work;
Has limited or restricted
means of entry or exit;
Is not designed for
continuous human
occupancy. 9
10. A space must meet all three of these criteria in order to
be classified as a confined space. 10
24. Oxygen Enriched Atmospheres
•Oxygen level above 23.5%.
•Causes flammable and combustible
materials to burn violently when
ignited.
•Hair, clothing, materials, etc.
•Oil soaked clothing and materials.
•Never use pure oxygen to ventilate.
•Never store or place compressed
tanks in a confined space.
24
25. Flammable Atmospheres
• 2 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
• Typical Ignition Sources:
– Sparking or electric tool.
– Welding / cutting operations.
– Smoking
25
27. Flammable
Atmospheres
Non-flammable
(Too “Rich”)
Flammable Flammable
Region
V
A
P Non-flammable
O (Too “Lean”)
R
Temperature
27
28. Toxic Atmospheres
• Product stored in a confined space:
Gases released when cleaning.
Materials absorbed into walls of confined space.
Decomposition of materials in the confined space.
• Work performed in a confined space:
Welding, cutting, brazing, soldering.
Painting, scraping, sanding, degreasing.
Sealing, bonding, melting.
• Areas adjacent to a confined space.
28
29. Hydrogen Sulfide
• Decomposition of materials. Human
waste.
• Rotten egg odor at low concentrations.
• Possibly no warning at high
concentrations.
PPM Effect Time
10 ppm Permissible Exposure Level 8 Hours
50 - 100 Mild Irritation - eyes, throat 1 Hour
200 - 300 Significant Irritation 1 Hour
500 -700 Unconsciousness, Death 1/2 - 1 Hour
>1000 Unconsciousness, Death Minutes
29
30. Carbon Monoxide
• Odorless, Colorless Gas.
• Combustion By-Product.
• Quickly collapse at high concentrations.
PPM Effect Time
35 Permissible Exposure Level 8 Hours
200 Slight headache, discomfort 3 Hours
600 Headache, discomfort 1 Hour
1000-2000 Confusion, nausea, headache 2 Hours
1000-2000 Tendency to stagger 1 1/2 Hours
1000-2000 Slight heart palpitation 30 Min.
2000-2500 Unconsciousness 30
30 Min.
31. Engulfment Hazards
•Loose, granular materials stored in
bins and hoppers - grain, sand, coal,
etc.
•Crusting and bridging below a
worker.
•Flooding of confined space.
•Water or sewage flow.
31
32. Engulfment
Examples of flowable solids
that may present an
engulfment hazard include
grain, sand, sawdust, gravel,
and plastic pellets.
32
33. Confined Space Entry - Hazards
Sudden releases of
fluid solids, such as When torrential forces
granulated salt, sugar, are suddenly released,
or sand, liquids, and people may be struck
dense gases can cause by moving objects , or
engulfment of persons be pushed helplessly
inside underground downstream.
tanks, or pits.
33
34. Other Hazards
•Noise
Amplified due to acoustics within the space.
Damaged hearing, affect communication.
•Slick / Wet Surfaces
Slips and falls.
Increased chance of electric shock.
•Falling Objects
Topside openings expose workers inside
confined space to falling objects.
34
36. Testing The Atmosphere
•Verify presence of safe work
atmosphere.
•Test all areas of a confined space.
– Top, Middle, Bottom
•Methane is lighter than air.
•Carbon Monoxide is the same as air.
•Hydrogen Sulfide is heavier than air.
•Oxygen Deficiency.
36
37. Test the Atmosphere
In this order:
Check for Oxygen Content:
– At least 19.5% and less than 23.5%
Check for Combustibles:
– Less than 10% of the LEL
Check for Toxic Gasses:
– Most commonly carbon monoxide
(PEL <35 ppm)
– or any other hazardous materials as
determined by the use of the space.
37
39. Ventilation
•First option to correct problems.
•Must be aware of hazards you are
trying to correct in the confined
space.
•Air intake in a safe location to draw
fresh air only.
•Continuous ventilation whenever
possible.
•Retest the confined space before
entry. 39
40. Ventilate the Space
Use mechanical ventilation
– Fans
– Air horns
Ventilate at the rate of at
least twenty (20) volumes
per hour
– Larger spaces require more
ventilation
Make sure air supply is not
contaminated
– Ventilation air supply must be
from fresh air uncontaminated
with flammables, toxins, etc. 40
41. LESSON 3
VENTILATING THE SPACE
Use mechanical
ventilation - such as fans
or forced air blowers
Make sure air supply is
not contaminated -
ventilation air supply
must be from fresh air
uncontaminated with
flammables, toxins, etc.
48. Other Control Techniques
Inerting (Note: Inerting with a gas
such as nitrogen or carbon dioxide
will result in an oxygen deficient
atmosphere)
Flushing
48
49. Isolate the Space
from all hazards
Close Valves
– Double block & bleed, or
– Blank flange
Empty the Space
– Depressurize, vent & drain
Lockout/Tagout Equipment
– Electrical sources
– Rotating/reciprocating parts
– Hazardous materials
Clean residue from the space49
54. Conduct a Tailboard Briefing
Entire crew must attend
– Attendants, entrants, entry supervisor
Review hazards of entry and work
Review PPE
Review procedure for contacting
rescue
– verify rescue available
Complete permit
54
55. Complete Entry Permit Form
Permit must be correctly and
completely filled out prior to
entry.
Permit must be activated by
Entry Supervisor’s signature to
be valid.
No entry is allowed without a
valid permit.
Permits are valid for up to 12
hours.
When work is completed,
permit and tailboard form
should be returned to safety.
Cancelled permits must be kept
on file for at least one year.
55
57. Test the Atmosphere
In this order:
Check for Oxygen Content:
– At least 19.5% and less than 23.5%
Check for Combustibles:
– Less than 10% of the LEL
Check for Toxic Gasses:
– Most commonly carbon monoxide
(PEL <35 ppm)
– or any other hazardous materials as
determined by the use of the space.
57
58. NOTICE:
Any time a limit is
exceeded, no matter what
the reason, all personnel
shall immediately exit the
space, and no others shall
enter until atmospheric
conditions are returned to
safe levels.
THERE ARE NO EXCEPTIONS TO THIS!
58
59. Atmosphere Testing Shall
Be Performed:
Prior to every entry when the
space is vacant;
After a 10 minute ventilation
period (if ventilation is
necessary);
At least hourly for permit-
required confined spaces.
More frequently, if conditions or
suspicions warrant.
59
60. Enter the Space and
Proceed with work:
An attendant shall be posted near
the entrance for the duration of the
work. He shall be in constant
communication with the entrants
while the job is in progress.
All entrants shall sign the sign in
log when entering the space and
sign out when exiting.
The attendant shall maintain the
permit and sign in log for the
duration of the work. 60
62. When the Job is Done:
Remove all personnel, tools,
and debris from the space.
Sign off the log.
Close the space.
Cancel the permit.
Review the job with the host
employer (hazards, problems,
other employers, etc.)
62
71. Entrant Responsibilities
To assure that the space has been
adequately ventilated, isolated,
emptied, or otherwise made safe for
entry.
To immediately exit a space, without
question, upon word of the attendant,
no matter what the reason.
To follow all safety rules and
procedures that apply to the job.
To be familiar with the work to be
performed and the procedures that
apply to the job.
To use the appropriate PPE whenever
necessary.
71
72. Attendant
An individual stationed outside one or
more permit spaces who monitors the
authorized entrants and performs all
attendant’s duties assigned in the
employer’s permit space program
72
73. Duties of Attendants
Knowledge of the hazards of the
space
Aware of possible behavioral effects
of hazard exposure in authorized
entrants
Continuously maintains an accurate
count of authorized entrants
73
74. Duties of Attendants
Remains outside the space
during operations until relieved
by another attendant
Communicates with authorized
entrants
Monitors activities inside and
outside the space
74
75. Duties of Attendants
Summons rescue and other
emergency services
Performs non-entry rescues as
specified by the employer's rescue
procedure
Performs NO duties that might
interfere with monitoring and
protecting the entrants 75
76. Supervisor Responsibilities
To assure adequate protection is
provided to the entrants by
verifying adequate
lockout/tagout and that all
hazards are securely isolated.
To support the attendant’s
authority in controlling access to
a confined space.
To verify that all personnel have
exited prior to closing the space.
To assure that all personnel
involved are aware of the hazards
associated with the space.
To assure that rescue services are
available prior to entry.
76
80. Confined Space Entry
Means of emergency rescue
must be readily available
to the confined space
entry attendant for
emergency
extrication of
entrants.
80
