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CFC - HIGHLY TOXIC
AND TOXIC MATERIALS |
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TOXIC AND HIGHLY TOXIC COMPRESSED GASES
-INDOOR STORAGE &
USE
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Gas detection system. A gas
detection system shall be provided to detect the presence of
gas at or below the PEL or ceiling limit of the gas for which
detection isprovided. The system shall be capable of
monitoring the discharge from the treatment system ator below
one-half the IDLH limit.
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Exception: A gas
detection system is not required for toxic gases when the
physiological warning threshold level for the gas is at a
level below the accepted PEL for the
gas. |
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Alarms. The gas detection system shall initiate a local alarm
and transmit a signal to a constantly attended control station
when a short-term hazard condition is detected. The alarm
shall be both visual and audible and shall provide warning
both inside and outside the area where gas is detected. The
audible alarm shall be distinct from all other
alarms.
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Exception: Signal
transmission to a constantly attended control station is not
required where not more than one cylinder of highly toxic or
toxic gas is stored.
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Shut off of gas supply. The gas detection system shall automatically close the
shutoff valve at the source on gas supply piping and tubing
related to the system being monitored for whichever gas is
detected.
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Exception: Automatic shutdown is not required for reactors utilized for the
production of highly toxic or toxic compressed gases where such reactors
are: |
| 1. |
Operated at pressures less than 15 pounds per square inch gauge (psig) (103.4 kPa).
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| 2. |
Constantly attended.
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| 3. |
Provided with readily accessible emergency shutoff valves
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Valve closure. Automatic closure of shutoff valve shall be in accordance with the following:
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| 1. |
When the gas-detection sampling point initiating the gas
detection system alarm is within a gas cabinet or exhausted enclosure, the shutoff valve in the gas
cabinet or exhausted enclosure for the specific gas detected shall automatically close.
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| 2. |
Where the gas-detection sampling point initiating the gas
detection system alarm is within a gas room and compressed gas containers are not in gas cabinets or exhausted enclosures,
the shutoff valves on all gas lines for the specific gas detected shall automatically close.
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| 3. |
Where the gas-detection sampling point initiating the gas
detection system alarm is within a piping distribution manifold enclosure, the shutoff valve for the compressed container
of specific gas detected supplying the manifold shall automatically close
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| EXCEPTION:
When the gas-detection sampling point initiating the gas detection system alarm is at a use location
or within a gas valve enclosure of a branch line downstream of a piping distribution manifold, the shutoff
valve in the gas valve enclosure for the branch line located in the piping distribution manifold
enclosure shall automatically close. |
