WORKING IN UTILITY VAULTS, SUB-FLOOR PITS AND OTHER
1. All employees whose job
requires them to enter or go down into underground utility vaults,
pits, manholes, or other subterranean enclosures, tanks, silos,
pipes, ducts, etc. are to be trained in confined space entry.
2. If you have been trained
in confined space entry, remember that the following steps are
to be taken before every entry:
a. Have your Department Supervisor
fill out a Confined Space Entry Permit.
Calibrated air sampling
equipment provided will be used to sample the air in the space. Results will be recorded on the Confined
Space Entry Form.
c. After the initial air sampling,
a ventilator fan will be used to supply fresh, clean (un-contaminated)
air to the confined space for at least 30 minutes prior to re-sampling.
After the space has been
ventilated for 30 minutes, the air will be sampled again and the
results recorded in the Confined Space Entry Form.
Air sampling results must fall within acceptable limits
before and during any confined space entry.
Oxygen levels must be between 19.5% and 23.5%; the lower
explosive limit (LEL) must be below 10%; the hydrogen sulfide
level must be below 10 parts per million (ppm); and the carbon
monoxide level must be below 35 ppm.
e. After the results from the
second set of air sampling have been recorded, and assuming the
results fall within acceptable levels, authorized workers can
enter the space. The ventilator fan must remain running for
the duration of the confined space entry.
will exit the space when a prohibited condition appears, or when
told to do so by the attendant or entry supervisor.