SAFE TY BY TOM O’CONNOR
By definition, confined spaces have
limited or restricted means for entry
and exit. They are large enough that a
person can enter to do work, but they are
not designed for continuous occupancy.
They can be above or below ground.
Examples include silos, vats, hoppers,
utility vaults, tanks, sewers, pipes, access
shafts, truck or rail tank cars, aircraft
wings, boilers, manholes and storage
bins. Ditches and trenches may also be
considered confined spaces if access
or egress is limited. Each environment
presents a unique set of potentially hazardous conditions.
Depending on the presence of
hazards, the confined space may be
classified as a permit-required confined
space (PRCS). Under its General Industry Standards, OSHA regulations address
detailed requirements for a permit that
must be established for entry. Special training related to the duties each
employee will perform in the confined
space is critical. Electric vaults and manholes—where electrical hazards exist
and only qualified workers enter—are
considered enclosed spaces. They are
not subject to the same regulations as a
PRCS and do not require a permit.
It is imperative to understand the difference between the requirements for a
PRCS and an enclosed space.
Hazards that turn confined spaces
into permit-required spaces include
chemical exposures; noise; dust; explosive or flammable atmospheres; radiation;
temperature extremes; poor visibility;
biological hazards; uncontrolled energy;
shifting or collapsing materials; and slip,
trip and fall hazards. However, the most
significant hazard is poor air quality and
lack of oxygen. Limited oxygen could lead
to a worker losing consciousness or worse.
When any of these hazards are present,
steps must be taken to eliminate or control
them through an entry-permit process.
The permit identifies who may enter, and
an attendant is assigned to monitor entry
into the space. The attendant must maintain communication with the workers and
perform nonentry rescues if needed. He or
she may not perform any other duties. If
entry is needed for rescue, the attendant
must summon rescue and emergency services per employer procedures.
The permit also requires air monitoring in the space to be performed and
recorded. Testing must be done before
entry and periodically while work is
being performed. These tests will need
to gauge oxygen, flammable and combustible gas and vapor, and toxin levels for
hazards, such as carbon monoxide and
The oxygen test must be done first.
Air usually contains about 20. 9 percent oxygen. By OSHA’s standards, the
minimum requirement is 19. 5 percent.
Anything below 16 percent will diminish mental effectiveness, visual acuity
and muscular coordination.
The next test is for flammable gases
and vapors. Once these tests are completed, tests must be performed for any
other potential toxins that may be present. This will depend on the space being
Continuous readings for all hazards
are needed while working in the space.
Continuous forced-air ventilation must
also be provided, and it must come from
a clean source.
Procedures for enclosed spaces differ
slightly from OSHA’s PRCS regulations.
While enclosed spaces still include the
need for testing the atmosphere before
entry, the testing procedure differs in
the application of forced ventilation and
periodic testing. If continuous forced-air
ventilation is provided, periodic testing
is not required although procedures
must be in place to ensure that employees will not be exposed to the hazards
posed by oxygen deficiency or fire. Of
course, though not required, testing is a
sure way to accomplish this. However, if
open flames are used in the space, tests
are mandatory and are to be performed
at least once each hour.
The two types of spaces also differ
in attendant responsibilities and rescue.
Unlike the PRCS attendant, an enclosed
space attendant may perform other
duties if he or she does not distract from
monitoring employees within the space.
The only requirement related rescue is,
“Employers shall provide equipment
to ensure the prompt and safe rescue of
employees from the enclosed space.”
While no construction standard currently exists for a PRCS, it is critical
that contractors implement procedures
consistent with the general industry requirements. They can save lives.
Regardless of a particular standard’s
applicability, failure to protect employees
can result in OSHA citation under the
general duty clause of the Occupational
Safety and Health Act. For more information about confined and/or enclosed
spaces, visit www.osha.gov.
I Feel So Confined
Working in confined spaces
THE OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION (OSHA)
estimates that 1. 6 million U.S. workers enter confined spaces every year. Unfortunately, nearly 100 workers are killed, and more than 5,000 other accidents occur
annually in such environments.
O’CONNOR is safety and regulatory affairs manager for Intec, a safety consulting, training and
publishing firm that offers on-site assistance and produces manuals, training videos and software
for contractors. He has significant experience working with national and international trade
associations with an expertise in government affairs. Reach him at firstname.lastname@example.org. IST