ONLINE SELF-STUDY
Permit Required Confined Spaces
OSHA 29 CFR 1910.146
Objectives
In this course, we will cover the following:
Definition of a confined space
Identify the difference between a confined
space and permit required confined space
Discuss potential confined space hazards
Outline responsibilities for the entrant, attendant
and entry supervisor
Identify rescue options
Identifying a Confined Space
What is a confined space?
A confined space is a space that:
is large enough to get the whole
body inside and perform work,
is not designed for continuous
occupancy (i.e., primary function is
not for human occupancy), and
has limited or restricted entrance or
exit.
It must have all three characteristics to be a confined space.
Identifying a Confined Space
What is limited or restricted entry or exit?
Physical configuration that requires
a person to twist or contort the
body or use hands to enter or exit
the space.
Safe egress is restricted by
obstructions within the space or by
the distance to reach the exit.
Note: Entry is defined as
breaking the plane of a confined
space with any part of the body.
Restricted exit
Exit not restricted
Identifying Confined Spaces
Examples of confined spaces
Manholes &
Sewers
Tanks
Boilers
Grain storage bins
Other examples include vaults, pipelines, tunnels, and open top spaces >4 feet deep
Identifying Confined Spaces
UNC-CH departments shall identify each space under their
jurisdiction which meets the definition of a confined space,
if any exist, and shall provide a list of such spaces to EHS.
The hazards of each permit space shall be catalogued on
the list.
Contact EHS (962-5507) for assistance with classifying
confined spaces.
Confined spaces shall be considered hazardous until an
evaluation is completed.
Hazards of Confined Spaces
Confined spaces can be deadly.
Some confined spaces are more hazardous than others.
Confined space conditions can change rapidly from
no hazards to life-threatening hazards.
Some confined spaces are so hazardous, a written
permit system is required for entry.
The hazards of confined spaces can often be
controlled or eliminated before entering.
Hazards of Confined Spaces
What are the main hazards of confined spaces?
• Hazardous atmospheres
• Engulfing materials
• Entrapment
• Mechanical (moving parts)
• Electricity
Hazards of Confined Spaces
What makes confined spaces so hazardous?
Analysis of 10 years of oxygen deficiency fatalities related
to nitrogen asphyxiation revealed:
In 80% of the incidents, the confined space had been entered before
without any problems by the same person who died.
In 40% of the incidents, the hazard was not present at the time of
initial entry.
In 89% of the incidents, the entries were authorized by supervisors.
In 35% of the incidents, the fatalities were supervisors.
Source: AIHA-Challenging Confined Spaces Teleweb
Hazard of Confined Spaces
When is a confined space so dangerous a written
entry permit system is required?
• When there is an actual or potential
“hazardous atmosphere”, or
• When the space contains material that can
engulf a person, or
• When the space is configured in a way that
can trap a person, or
• When there is any other recognized serious
safety and health hazard.
Hazard Identification
A “hazardous atmosphere” in a confined space has one or
more of the following:
Flammable gas, mist or vapor
Flammable dusts
Oxygen content below 19.5% or above 23.5%
Air contaminant concentrations that would cause
death, incapacitation, or permanent health problems
You must do air monitoring to
determine if a hazardous
atmosphere exists.
Hazard Identification
Hazardous Atmospheres – Flammable Gases,
Vapors and Dusts
Flammable gases, vapors or dusts will ignite
from a spark or flame if above a level in the
air called the “lower flammable limit” (LFL).
Gas or vapor levels higher than 10% of the
LFL are considered hazardous and the
confined space cannot be entered until levels
are reduced.
The LFL and upper flammable limit (UFL) set
the boundaries of the flammable range.
LFL is sometimes called “LEL” – “lower explosive limit”
Hazard Identification
Example of flammable gas levels - Methane
Air
0%
Air
100%
Too Rich
Too Lean
Boom!
Methane
0%
5.3%
LFL
Methane
100%
15.0%
UFL
An open flame or a spark will cause an explosion when the methane amount is
between 5.3% and 15% (i.e., the LFL and UFL for methane).
Hazard Identification
Hazardous Atmospheres – Oxygen Deficiency
A reduction in oxygen may be caused by lack of ventilation, rusting,
microbe activity, or replacement by another gas.
Lack of oxygen can cause a person to immediately collapse and die.
Normal air contains 21% oxygen. A space with oxygen content
below 19.5 % is considered “oxygen deficient”.
21% 19.5%
0%
Oxygen content
Oxygen deficiency exists
Hazard Identification
Effects of Oxygen Deficiency
% Oxygen
Symptoms
19.5% - 16%
Fatigue, mild impaired coordination
16% - 12%
Increased breathing rate and pulse; impaired
coordination, perception or judgment
12% - 10%
Further increased breathing rate, blue lips, mental
confusion
10% - 8%
Fainting, nausea, vomiting, mental confusion within few
minutes
8% - 6%
Collapse, death within 8 minutes
6% - 0%
Coma within 40 seconds, death
Using an “inerting gas” like nitrogen to counteract flammable
vapors will result in an oxygen deficiency.
Hazard Identification
A word about oxygen-enriched atmospheres
A confined space with an oxygen
amount above 23.5% is considered
“oxygen-enriched”.
A potential source of “extra” oxygen
is a leaking oxygen cylinder used for
an oxy-acetylene torch.
Oxygen above 23.5% is a fire or
explosion hazard.
Green tanks contain oxygen
Hazard Identification
Hazardous Atmospheres – Toxic Chemicals
At very high levels, chemicals in the air can
be immediately life-threatening or cause
permanent bodily harm.
Even at lower levels, chemicals in the
air can still cause harm.
Some chemicals have “occupational
exposure limits” (OELs) which will cause
harm if exceeded.
Even non-toxic or low-toxic chemicals can replace
oxygen if levels are high enough.
Hazard Identification
Hazardous Atmosphere – Toxic Chemicals
The most common toxic chemicals in confined
spaces fatalities are hydrogen sulfide and
carbon monoxide.
Other toxic chemicals can include welding
fumes, vapors from liquid residues in storage
tanks, or chemical products used in the confined
space.
Chemicals can quickly reach toxic levels in the
air of a confined space, especially gases, solvent
vapors or sprayed products.
Contact EHS (962-5507) for more information on toxic chemicals.
Hazard Identification
Hazardous Atmospheres–Hydrogen Sulfide (H2S)
Hydrogen sulfide gas is produced by decaying matter and is
commonly found in sewers.
It can be instantly fatal at higher levels in a confined space.
The OELs for H2S prescribed by EHS are 1 ppm as a 8-hr
TWA1 and 5 ppm as a 15-min STEL2.
30
100
200
600
1000
2000
H2S in parts per million (ppm)
Smell
strong
odor
Loss of
smell
Coughing,
red eyes
Unconscious in
30 min.
Instant
collapse
Death in
minutes
1 Time-Weighted Average, 2 Short-Term
Exposure Limit
Hazard Identification
Hazardous Atmospheres – Carbon Monoxide (CO)
Carbon monoxide comes from
operating internal combustion
engines in or near a confined space.
Propane-powered engines also emit
carbon monoxide.
Fatal levels of CO are quickly
reached in confined spaces.
The OEL for CO is 25 ppm
as an 8-hr TWA. To see the
effects of CO, click here
Hazard Identification
What are the Hazards of Engulfing Material?
Engulfing materials include liquids or loose
solids such as grain, sand or other granular
material.
People cannot escape when caught in
moving loose solids and can suffocate.
Workers often get engulfed when inlet or
outlet lines are inadvertently opened or
activated.
Hazard Identification
What is Entrapment?
The space is configured in a way that can trap a worker, for
example, sides sloping towards the center
Gravel hopper
Sawdust Cyclone
Hazard Identification
Other Recognized Hazards
Electrical lines, steam lines or
hydraulic lines
Mechanical hazards
(moving parts)
Hazards caused by the work
(welding, painting etc.)
Controlling the Space
The hazards of a confined space can be controlled in
the following ways:
• Prevent employee entry.
• Remove or reduce hazards in the space
first, before a person enters.
• If hazard cannot be removed or
controlled, you must use a written permit
system to enter safely.
Controlling the Space
Warning employees and controlling access
Post warning signs at the entrance of
confined spaces.
Limit employee access to confined spaces by
using entry barriers or locks.
Make sure that unauthorized workers do not
enter the confined space.
Hazard Control
How To Control Hazardous Atmospheres
Drain or pump out liquid contents, if
any.
Blank off all in-feeding lines.
Test air and ventilate.
Continue ventilating constantly.
If possible, remove any sludge from
outside the confined space.
Exit space if conditions deteriorate.
Hazard Control
Hazardous Atmospheres Dangers
It is difficult to eliminate hazardous
atmospheres in most sewers lines.
Tank sludge or sewer sludge can
release toxic gases during cleanup.
Toxic or flammable gases can exist
in pockets or layers within the space.
Hazard Elimination
How To Eliminate Physical Hazards
Lock-out and Tag-out moving parts
Blank or block steam pipes and
product in-feeding pipes.
De-energize electrical parts or wiring
If Hazards Can’t Be Eliminated
If hazards cannot be completely eliminated, there are
only two options:
a complete written permit system, or
“alternate procedures.”
Both require training of employees.
Entry into a Confined Space
How is entry into a confined space classified?
Written Permit System – required for any high
hazard entry
Alternate Entry Procedures – allowed for
controlled atmospheric hazards only
Reclassified Non Permit – allowed only if all
hazards are eliminated
Hazards must be determined before entering a confined space.
Confined Spaces Entry Procedures
What Determines Your Options
If the atmosphere can’t be controlled or there
are other uncontrolled hazards, you must use
the written permit system for entry into a
confined space.
If you are unsure about the hazards, you must
assume a high hazard and use a written permit
system for entry.
Only if you are sure there are no hazardous
atmospheres or other hazards, can you avoid
the required permit procedures for entry.
Confined Space Entry Procedures
What are “alternate entry procedures”?
If the only hazard is atmospheric (toxic gas or oxygen
deficiency) and it is controlled by continuous ventilation, then
you may use less restrictive alternate entry procedures.
These procedures have fewer requirements.
Don’t assume that the only hazard is atmospheric without
investigation and reliable information.
Confined Space Entry Procedures
What are alternate entry requirements?
Employees must be trained on confined
space hazards,
The atmosphere in the confined space
must be tested before and during entry,
Continuous ventilation must be used,
If a hazardous atmosphere is detected,
or ventilation stops, the space must be
promptly exited.
Confined Space Entry Procedures
What are alternate entry requirements?
The acceptable concentration for LEL is
lowered to <5% as a protection factor.
Provide vehicle and pedestrian barriers.
No harness or lifeline required.
However, EHS recommends entrants wear
a harness and a have a retrieval device in
the vicinity to aid in rescue during medical
emergencies such as heart attacks.
Confined Space Entry Procedures
What are reclassified non-permit entry requirements?
If all hazards are eliminated (as opposed to controlled), then
you may reclassify a space as non-permit. OSHA expects
that this option will apply primarily to spaces containing
hazardous energy sources or engulfment hazards.
Employees must be trained on confined space hazards.
The atmosphere in the confined space must be tested before
and during entry.
If the gas monitor alarms the entrant must evacuate the
space and reclassify the space as a permit space until the
contaminant is identified and eliminated.
Confined Space Entry Procedures
What are reclassified non-permit entry requirements?
Acceptable atmospheric conditions are listed below:
Oxygen between 19.5% and 23.5%
Flammable gases (LEL) is at or lower than 10%
Carbon monoxide is at or lower than 25 parts per million (ppm)
Hydrogen sulfide is at or lower than 5 ppm
Provide vehicle and pedestrian barriers.
No harness or lifeline required.
However, EHS recommends entrants wear a harness and a
have a retrieval device in the vicinity to aid in rescue during
medical emergencies such as heart attacks.
Confined Space Entry Procedures
The Importance of Air Monitoring
Air monitoring is required whenever
there is a possibility of hazardous
atmospheres.
Atmospheric conditions can
change quickly in a confined
space.
A portable gas monitor with an
alarm should be used by the
person entering the confined space
and checked frequently.
Confined space gas monitor
Confined Space Entry Procedures
Acceptable Atmospheric Conditions
Confined Space entry may proceed only if tests indicate:
Oxygen between 19.5% and 23.5%
Flammable gases (LEL) is at or lower than 10%
Carbon monoxide is at or lower than 25 ppm
Hydrogen sulfide is at or lower than 5 ppm
The amount(s) of other identified air contaminants is/are at
or lower than the OEL prescribed by EHS
Detected hazards must be eliminated or controlled.
Confined Space Entry Procedures
Gas Monitor Alarm Setpoints
Alarm setpoints must be set low enough to allow self-rescue
before atmospheric conditions impair an entrant.
EHS requires the following gas monitor alarm settings which
are based on the most stringent OELs for the hazards:
Sensor
Low
High
STEL
TWA
O2
19.5
23.5
--
--
LEL
10
20
--
--
CO
25
100
100
25
H2S
5
10
5
1
Contact EHS (962-5507) for assistance with setpoints.
Confined Space Entry Procedures
Atmospheric Testing Frequency
EHS recommends performing atmospheric tests every 5 mins
for the first 20 minutes of the entry, then every 20 minutes
thereafter.
The testing frequency will help identify atmospheric changes
before alarm setpoints on the gas monitor are reached.
This frequency applies to testing for alternate entry
procedures, reclassified non-permit, and permit-required
spaces.
Confined Space Entry Procedures
Limitations of Air Monitoring Instruments
LEL readings for gases other than
the calibration gas may be incorrect.
Temperatures outside of the
operation range for the monitor may
affect LEL readings.
The presence of any detectable LEL
indicates an abnormal condition and
the source should be evaluated.
Confined Space Entry Procedures
The Importance of Daily Bump Testing
Perform a daily bump test prior to using a gas monitor.
On a given day, 1 in every 2,500 untested gas monitors
will fail to respond to a dangerous concentration of gas.
A bump test is a functionality test of sensors and alarms.
Perform a bump test by briefly exposing the instrument to
known concentrations of the target gases and verifying
that the instrument responds.
Source: Industrial Scientific
Confined Space Entry Procedures
Ventilation of Confined Spaces
Fresh air blowers or exhaust fans
are typically used.
A blower intake must be placed in
an area of clean air, (i.e., upwind of
combustible engine exhaust).
Exhaust ventilation must be used
when welding or using chemicals in
a confined space.
Watch out for pockets of
unventilated contaminated air.
Don’t place a blower intake near a
running engine!
Written Permit Space Program
If employees enter permit spaces, the employer shall
develop and implement a written permit space
program.
Written Permit Space Program
What are the goals of a written program?
Identify and evaluate permit space hazards
Ensure safe entry operations
Provide proper entry equipment
Designate and train entry team
Develop rescue emergency procedures
Perform annual program review
Written Permit Space Program
What is required in a written permit program?
A written permit for each entry
Extensive employee training
Employee assigned duties
The Written Permit
The permit states what is done and who does it:
Provides written entry authorization,
Describes each individual’s roles and
responsibilities,
Specifies safety equipment
and respiratory protection,
Tells how long the job will take,
States hazards found in the space.
The Written Permit
The written permit also includes the following:
• Methods used to control the hazards
• Acceptable entry conditions
• Necessary equipment including PPE
• Air monitoring testing results
• Communication procedures
• Name and telephone of the rescue service
Designated Jobs
Any permit-required confined space entry has
designated jobs for employees:
Entrant – person who enters into the
permit space
Attendant – person stationed outside
the space who monitors the entrant
Entry Supervisor – person
responsible for planning, authorizing,
and terminating the entry
Each position has assigned duties.
Permit System Job Duties
Entrant’s Knowledge and Duties
Knows and understand the hazards in the space,
Knows and uses equipment properly,
Is able to communicate with the attendant.
Permit System Job Duties
Entrant’s Knowledge and Duties
Knows what the acceptable entry
conditions for the space are,
Knows how to contact the
attendant if conditions become
unacceptable,
Exits the space when ordered,
when alarm sounds, or when
dangerous situation is noted.
Permit System Job Duties
Attendant’s Knowledge and Duties
Knows and understands the hazards in the space,
Knows the behavioral effects from exposures to
hazards in the space,
Knows and tracks who is in the space at all times,
Warns away an unauthorized person who
gets near or enters the space.
Permit System Job Duties
Attendant’s Knowledge and Duties
Remains outside the confined space at all
times and monitors activity constantly,
Communicates with entrants to monitor
conditions and knows when to order an
evacuation,
Knows how and when to summon emergency help
and does not enter space to rescue,
Knows how to perform non-entry rescues.
Permit System Job Duties
Entry Supervisor Knowledge and Duties
Knows the hazards in the confined space,
Verifies completion of all tests and permit procedures,
Terminates or cancels the permits as needed,
Verifies that rescue services are available,
Removes any unauthorized person from the space,
The attendant and entry supervisor may be the same person.
Permit System Job Duties
Completion of Entry Duties
If the entry was successfully completed, the Attendant shall:
Indicate such by checking the appropriate block on the permit;
Oversee the completion of post-entry actions listed on the permit;
Verify completion by signing in the appropriate location;
Add any pertinent information concerning the entry on the permit;
Return the permit to the Entry Supervisor.
Permit System Job Duties
Program Records Coordinator Duties
Departments shall also designate a departmental Program
Records Coordinator that is responsible for maintaining
cancelled permits and documentation.
Canceled Permits shall be retained by the Coordinator not
less than one year following the date of entry.
They, along with the entry supervisor, conduct annual
program reviews.
They provide EHS with training records, confined space
evaluation forms and any changes associated with the hazard
status of confined spaces.
Safety/Rescue Equipment
Depending on the hazards of the space and the work
activities the following equipment may be required:
Hard hat
Ladder
Fire
extinguisher
Goggles
Radio
Retrieval device & ventilation equipment
Safety/Rescue Equipment
Respirators may be required to enter a confined
space safely
Respirators must be worn to enter a space
with an oxygen deficiency or toxic chemical
levels above the PEL.
For these conditions, a respirator that
supplies fresh air is recommended for
use in a confined space.
EHS employees are the only campus
employees trained or fit tested with supplied
air respirators. Other employees are not
permitted to enter spaces with oxygen
deficiency or toxic levels above the OEL.
Procedures for Joint Spaces
There may be situations in which a department
must perform work in a confined space
controlled by another department.
The requesting Entry Supervisor or representative must
coordinate with and obtain approval from the UNC-CH
department controlling the space prior to entry.
Upon completion of the entry, the Entry Supervisor shall
immediately meet with the controlling entity to provide
information on unexpected hazards or problems within the
space of which the controlling entity was unaware.
Procedures for Contractors
Contractors must use their permit system that meets the
requirements of 29 CFR 1910.146 or other applicable
standard.
Contractors and their employees must have training that
meets the requirements of 29 CFR 1910.146 or applicable
standard.
The responsible UNC-CH supervisor must inform the
contractor of the hazards within the space.
Procedures for Contractors
If University employees shall enter the space with contracted
employees, the UNC-CH supervisor shall ensure that entry
operations are coordinated with the contractor or designee.
The Contractor or designee shall meet with the responsible
UNC-CH supervisor after completion of the entry to
provide notification of:
Any new permanent hazards created by the work; and/or
Any unidentified hazards encountered during the entry.
Rescue in a Confined Space
Confined space rescue is very dangerous
60% of all confined space fatalities
are would-be rescuers.
Rescuers often enter a confined
space without thinking about the
hazards.
Rescues cannot be done without
proper equipment and training.
Rescue Services
Using Outside Services
The campus uses South Orange Rescue
Squad for confined space rescues.
SORS periodically practices mock
rescues in campus confined spaces.
Call 911 (Public Safety) to summon SORS
when rescue is required.
Tell the operator the location and about
the hazards inside the space.
Non-entry Rescue
What is a non-entry rescue?
Non-entry rescue is retrieving a person
out of a confined space without going
into the space.
Entrants must wear full body
harnesses with a retrieval line
attached.
Best suited for manholes and tanks
and cannot be used in every situation.
Non-entry Rescue
Non-Entry Rescue Equipment
It is usually impossible to pull a person
out of a confined space unassisted.
A retrieval line is attached to a
mechanical device or a fixed anchor
point outside the space.
The mechanical device must be capable
of lifting a person from a space.
Special rescue tripods are available.
Employee Training
General Requirements
Train before assigning duties
Train before changing duties
Train whenever operations present a new hazard
Employee Training
General Requirements
Retrain whenever there is reason to believe:
• There are deviations from the established
procedures,
• There are inadequacies in the employee’s knowledge
of procedures.
Employee Training
General Requirements
Training must establish proficiency.
The employer must certify that this training has been done and
meets the confined space regulations.
Annual Program Review
The Program Records Coordinator/Entry Supervisor shall
review the effectiveness of the Program annually using
canceled permits and other documentation from the preceding
twelve months.
The department shall view and initiate whatever changes
necessary to address confirmed weaknesses.
Contact EHS (962-5507) to assist with the annual review and
provide the format to conduct the review.
UNC-CH EHS would like to acknowledge the
Washington State Department of Labor &
Industries for providing portions of the training
content.