Enclosed space. A working space, such as a manhole,
vault, tunnel, or shaft, that has a limited means of egress or entry, that is
designed for periodic employee entry under normal operating conditions, and
that, under normal conditions, does not contain a hazardous atmosphere, but may
contain a hazardous atmosphere under abnormal conditions.
(a) General. This section covers enclosed
spaces that may be entered by employees. It does not apply to vented vaults if
the employer makes a determination that the ventilation system is operating to
protect employees before they enter the space.
This section applies to routine entry into enclosed
spaces. If, after the employer takes the precautions given in this section and
in Section 2943, the hazards remaining in the
enclosed space endanger the life of an entrant or could interfere with an
entrant's escape from the space, then entry into the enclosed space shall meet
the permit space entry requirements of Article 37 of the Construction Safety
Orders or Section
5157 of the General Industry Safety
Orders.
NOTE to subsection (a): Entries into enclosed spaces
conducted in accordance with the permit space entry requirements of Article 37
of the Construction Safety Orders or Section
5157 of the General Industry Safety
Orders are considered as complying with this section.
(b) Safe Work Practices.
(1) Written, understandable safe work
practices for entry into, and work in enclosed spaces and for rescue procedures
shall be developed, implemented, and provided to affected employees.
(2) Safe work practices shall conform to the
applicable requirements of this section and shall include provision for the
surveillance of the surrounding area to avoid hazards such as drifting vapors
from tanks, piping and sewers.
(3)
For multi-employer worksites, the procedures shall address how all the affected
employers will coordinate their work activities, so that operations of one
employer will not endanger the employees of any other employer. If the
permit-required confined space requirements of Section
5157 or Article 37 of the CSO or
the requirements of Section
8355 apply to one or more of the
other employers, then the procedures shall also include coordination with those
employers.
(c) Training.
Employees, including attendants, shall be trained in the nature of the hazards
involved, the necessary precautions to be taken, the use of protective
equipment and emergency equipment, the enclosed-space entry procedures, rescue
procedures, and safe work practices, including instructions as to the hazards
they may encounter.
(d) Attendants.
While work is being performed in the enclosed space, an attendant with
first-aid training shall be immediately available outside the enclosed space to
provide assistance if a hazard exists because of traffic patterns in the area
of the opening used for entry. The attendant is not precluded from performing
other duties outside the enclosed space if these duties do not distract the
attendant from monitoring employees within the space or ensuring that it is
safe for employees to enter and exit the space.
NOTE: Section
2943(b)(4)
requires an attendant while work is being performed in a manhole or vault
containing energized electrical equipment.
(e) Rescue Equipment. Employers shall provide
equipment to ensure the prompt and safe rescue of employees from the enclosed
space.
(f) Evaluating Potential
Hazards. Before any entrance cover to an enclosed space is removed, the
employer shall determine whether it is safe to do so by checking for the
presence of any atmospheric pressure or temperature differences and by
evaluating whether there might be a hazardous atmosphere in the space. Any
conditions making it unsafe to remove the cover shall be eliminated before the
cover is removed.
NOTE to subsection (f): The determination called for in
this subsection may consist of a check of the conditions that might foreseeably
be in the enclosed space. For example, the cover could be checked to see if it
is hot and, if it is fastened in place, could be loosened gradually to release
any residual pressure. An evaluation also needs to be made of whether
conditions at the site could cause a hazardous atmosphere, such as an
oxygen-deficient or flammable atmosphere, to develop within the
space.
(g) Removing Covers.
When covers are removed from enclosed spaces, the opening shall be promptly
guarded by a railing, temporary cover, or other barrier designed to prevent an
accidental fall through the opening and to protect employees working in the
space from objects entering the space.
(h) Hazardous Atmosphere. Employees shall not
enter any enclosed space while it contains a hazardous atmosphere, unless the
entry conforms to Article 37 of the Construction Safety Orders for construction
or Section
5157 of the General Industry Safety
Orders.
NOTE to subsection (h): See Section
2943(b) for
additional requirements on attendants for work in manholes and
vaults.
(i) Calibration of
Test Instruments. Test instruments used to monitor atmospheres in enclosed
spaces shall be kept in calibration and shall have a minimum accuracy of + or -
10 percent.
(j) Testing. Before an
employee enters an enclosed space, the air shall be tested with a direct
reading meter or similar equipment capable of collection and immediate analysis
of data samples without the need for an offsite evaluation. Testing is to
determine whether dangerous air contamination, oxygen enrichment and/or an
oxygen deficiency, and flammable gases and vapors exist in the enclosed space.
The test for flammable gases or vapors shall be performed after oxygen testing
to ensure the accuracy of the test for the flammability. The direct reading
meter shall be approved for use in such explosive or flammable conditions as
required by Section
2540.2. A written record of such
testing results shall be made and kept at the work site for the duration of the
work. Affected employees and/or their representative shall be afforded an
opportunity to review and record the testing results.
(1) Where interconnected spaces are blinded
off as a unit, each space shall be tested and the results recorded and the most
hazardous condition so found shall govern procedures to be followed.
(2) If dangerous air contamination, oxygen
enrichment and/or oxygen deficiency does not exist within the space, as
demonstrated by tests, entry into and work within the space may proceed subject
to the following provisions:
(A) Testing
shall be conducted with sufficient frequency to ensure that the development of
dangerous air contamination, oxygen enrichment and/or oxygen deficiency does
not occur during the performance of any operation.
(B) If the development of dangerous air
contamination, oxygen enrichment and/or an oxygen deficiency is imminent, the
requirements prescribed by Article 37 of Construction Safety Orders or Section
5157 of the General Industry Safety
Orders shall also apply.
(k) Ventilation and Monitoring. If dangerous
air contamination, flammable gases or vapors are detected or if an oxygen
deficiency is found, forced-air ventilation shall be used to maintain oxygen at
a safe level, to prevent dangerous air contamination, and accumulation of
hazardous concentration of flammable gases and vapors. A continuous monitoring
program is required to ensure that no increase in air contaminants, flammable
gas or vapor concentration above safe levels occurs within in the enclosed
space.
(l) Specific Ventilation
Requirements. If continuous forced-air ventilation is used, it shall begin
before entry is made and shall be maintained long enough for the employer to be
able to demonstrate that a safe atmosphere exists before employees are allowed
to enter the work area. The forced-air ventilation shall be so directed as to
ventilate the immediate area where employees are present within the enclosed
space and shall continue until all employees leave the enclosed
space.
(m) Air Supply. The air
supply for the continuous forced-air ventilation shall be from a clean source
and shall not increase the hazards in the enclosed space.
(n) No source of ignition shall be introduced
until the implementation of appropriate provisions of this section have ensured
that dangerous air contamination due to oxygen enrichment, flammable and/or
explosive substances does not exist.
(o) Open Flames.
(1) If open flames are used in enclosed
spaces, a test for flammable gases and vapors shall be made immediately before
the open flame device is used and at least once per hour while the device is
used in the space. Testing shall be conducted more frequently if conditions
present in the enclosed space indicate that once per hour is insufficient to
detect hazardous accumulations of flammable gases or vapors.
(2) Whenever oxygen-consuming equipment such
as salamanders, plumbers' torches or furnaces, and the like, are to be used,
measures shall be taken to ensure adequate combustion air and exhaust gas
venting.
(p) To the
extent feasible, provision shall be made to permit ready entry and
exit.
(q) Where it is not feasible
to provide for ready exit from spaces equipped with automatic fire suppression
systems employing harmful design concentrations of toxic or oxygen-displacing
gases, or total foam flooding, such systems shall be deactivated. Where it is
not practical or safe to deactivate such systems, the provisions of Section
5144 related to the use of
respiratory protective equipment shall apply during entry into and work within
such spaces and entry of the space shall be in accordance with Article 37 of
the Construction Safety Orders or Section
5157 of the General Industry Safety
Orders.