Confined Spaces
Chapter 296-809, WAC |
Effective
Date: 05/01/04 |
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Acceptable
entry conditions
The conditions that must exist
in a permit-required confined space to allow safe entry and
work
Attendant
An individual stationed outside one
or more permit-required confined spaces to monitor the entrants
Blanking or blinding
The absolute closure of a pipe, line,
or duct by fastening a solid plate (such as a spectacle blind
or a skillet blind) that completely covers the bore. It is capable
of withstanding the maximum pressure of the pipe, line, or duct
with no leakage beyond the plate.
Confined space
A space that is all
of the following:
- Large enough and arranged so an employee could fully enter
the space and work.
- Has limited or restricted entry or exit. Examples of spaces
with limited or restricted entry are tanks, vessels, silos,
storage bins, hoppers, vaults, excavations, and pits.
- Not primarily designed for human
occupancy.
Double block and
bleed
The closure of a line, duct, or pipe
by closing and locking or tagging 2 in-line valves and by opening
and locking or tagging a drain or vent valve in the line between
the 2 closed valves.
Emergency
Any occurrence (including any
failure of hazard control or monitoring equipment) or event
internal or external to the permit-required confined space that
could endanger authorized entrants.
Engulfment
The surrounding capture of a person
by a liquid or finely divided (flowable) solid substance that
can be inhaled to cause death by filling or plugging the respiratory
system or that can exert enough force on the body to cause death
by strangulation, constriction, or crushing.
Enter (entry)
The action by which a person passes
through an opening into a permit-required confined space and
includes work activities in that space. Entry is considered
to have occurred as soon as any part of the entrant’s
body breaks the plane of an opening into the space.
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Note:
If the opening is large enough for the worker to fully enter
the space, a permit is required even for partial body entry.
Permits aren't required for partial body entry where the
opening isn't large enough for full entry, although other
rules such as chapter 296-803 WAC, Lockout-Tagout, and chapter
296-841
WAC, Airborne contaminants may apply.
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Entrant
An employee who is authorized by the
employer to enter a permit-required confined space
Entry permit (permit)
The written or printed document that
is provided by you to allow and control entry into a permit-required
confined space and that contains the information required in
WAC 296-809-500, Permit Entry
Procedures.
Entry supervisor
The person (such as the employer, crew
leader, or crew chief) responsible for:
- Determining
if acceptable entry conditions are present at a permit-required
confined space where entry is planned;
- Authorizing entry and overseeing
entry operations
and
- ATerminating entry as required.
Hazardous atmosphere
An atmosphere that may expose employees
to the risk of death, incapacitation, impairment of ability
to self-rescue (that is, escape unaided from a permit-required
confined space), injury, or acute illness caused by one or more
of the following:
- Flammable
gas, vapor, or mist in excess of 10% of its lower flammable
limit (LFL).
- Airborne combustible dust at a concentration
that meets or exceeds its LFL.
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Note:
This concentration may be approximated
as a condition in which the dust obscures vision at a distance
of 5 feet
(1.52 m) or less.
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- Atmospheric oxygen concentration
below 19.5% or above 23.5%.
- Atmospheric concentration of any
substance which may exceed a permissible exposure limit. For
additional information about atmospheric concentration, see
chapter 296-62
WAC, Parts F, G, and I, General Occupational Health Standards
and chapter 296-841
WAC, Airborne contaminants.
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Note:
An airborne concentration of a substance
that isn't capable of causing death, incapacitation, impairment
of ability to self-rescue, injury, or acute illness due
to its health effects isn't covered by this definition. |
- Any other atmospheric condition that is
immediately dangerous to life or health.
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Note:
You can find guidance on establishing
acceptable atmospheric conditions for air contaminants,
which have no WISHA-determined doses or permissible exposure
limits using other sources of information, such as:
- Material safety data sheets
required by WAC
296-800-170, Employer Chemical Hazard Communication.
- Published information
- Internal documents.
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Hot work permit
A written authorization to perform
operations, for example, riveting, welding, cutting, burning,
and heating, that can provide a source of ignition.
Immediately dangerous
to life or health (IDLH)
Any of the following conditions:
- An immediate or delayed threat to
life
- Anything that would cause irreversible
adverse health effects
- Anything that would interfere with
an individual’s ability to escape unaided from a permit-required
confined space.
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Note:
Some materials hydrogen fluoride gas
and cadmium vapor, for example may produce immediate transient
effects that, even if severe, may pass without medical attention,
but are followed by sudden, possibly fatal collapse 12 to
72 hours after exposure. The victim “feels normal”
after recovery from transient effects until collapse. Such
materials in hazardous quantities are considered to be “immediately”
dangerous to life or health (IDLH). |
Inerting
The displacement of the atmosphere
in a permit-required confined space by a noncombustible gas
(such as nitrogen) to such an extent that the resulting atmosphere
is noncombustible.
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Note:
This procedure produces an IDLH oxygen-deficient atmosphere.
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Isolation
The process by which a permit-required
confined space is removed from service and completely protected
against the release of energy and material into the space by
such means as:
- Blanking or blinding
- Misaligning or removing sections
of lines, pipes, or ducts
- A double block and bleed system
- Lockout or tagout of all sources
of energy
or
- Blocking or disconnecting all mechanical
linkages.
Line breaking
The intentional opening of a pipe,
line, or duct that is or has been carrying flammable, corrosive,
or toxic material, an inert gas, or any fluid at a volume, pressure,
or temperature capable of causing injury.
Non-permit confined
space
A confined space that does not
contain actual hazards or potential hazards capable of causing
death or serious physical harm.
Oxygen deficient
atmosphere
An atmosphere containing less than
19.5% oxygen by volume
Oxygen enriched atmosphere
An atmosphere containing more than
23.5% oxygen by volume
Permit-required
confined space or permit space
A confined space that has one or more
of the following characteristics capable of causing death or
serious physical harm:
- Contains or has a potential to contain
a hazardous atmosphere
- Contains a material with the potential
for engulfing someone who enters
- Has an internal configuration that
could allow someone entering to be trapped or asphyxiated
by inwardly converging walls or by a floor, which slopes downward
and tapers to a smaller cross section
- Contains any physical hazard. This
includes any recognized health or safety hazards including
engulfment in solid or liquid material, electrical shock,
or moving parts
- Contains any other recognized serious
safety or health hazard that could either:
- Impair the ability to self-rescue
or
- Result in a situation that presents an immediate danger
to life or health.
Permit-required confined space program
An overall program for:
- Controlling
and appropriately protecting employees from permit-required
confined space hazards;
and
- Regulating employee entry into permit-required
confined spaces.
Prohibited condition
Any condition in a permit-required
confined space that isn't allowed by the permit during the authorized
entry period.
Rescue service
The personnel designated to rescue
employees from permit-required confined spaces.
Retrieval system
The equipment used for non-entry rescue
of persons from permit-required confined spaces, such as a retrieval
line, full-body harness or wristlets, and a lifting device or
anchor.
Testing
The process of identifying and evaluating
the hazards that entrants may be exposed to in a permit-required
confined space. Testing includes specifying the tests that are
to be performed in the permit-required confined space.
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Note:
Testing allows employers to devise and
implement adequate controls to protect entrants during entry,
and to determine if acceptable entry conditions are present.
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