Page 506 - 2018_IFC

HIGHLY TOXIC AND TOXIC MATERIALS

tanks or cylinders are equipped with approved both audible and visible and shall provide warning
excess flow or reduced flow valves, the worst-case both inside and outside the area where gas is
release shall be determined by the maximum achiev- detected. The audible alarm shall be distinct from all
able flow from the valve as determined by the valve other alarms.
manufacturer or compressed gas supplier. Reduced Exception: Signal transmission to a constantly
flow and excess flow valves shall be permanently attended control station is not required where not
marked by the valve manufacturer to indicate the
more than one cylinder of highly toxic or toxic
maximum design flow rate. Such markings shall gas is stored.
indicate the flow rate for air under normal tempera-
ture and pressure. 6004.2.2.10.2 Shut off of gas supply. The gas-
detection system shall automatically close the shut-
TABLE 6004.2.2.7.5 off valve at the source on gas supply piping and tub-
RATE OF RELEASE FOR CYLINDERS AND PORTABLE TANKS
ing related to the system being monitored for
VESSEL TYPE NONLIQUEFIED (minutes) LIQUEFIED (minutes) whichever gas is detected.
Containers 5 30
Exception: Automatic shutdown is not required
Portable tanks 40 240 for reactors utilized for the production of highly
toxic or toxic compressed gases where such reac-
6004.2.2.8 Emergency power. Emergency power shall tors are:
be provided for the following systems in accordance
with Section 604: 1. Operated at pressures less than 15 pounds
per square inch gauge (psig) (103.4 kPa).
1. Exhaust ventilation system.
2. Constantly attended.
2. Treatment system.
3. Provided with emergency shutoff valves
3. Gas detection system.
that have ready access.
4. Smoke detection system. 6004.2.2.10.3 Valve closure. Automatic closure of
5. Temperature control system. shutoff valves shall be in accordance with the fol-
lowing:
6. Fire alarm system.
1. Where the gas-detection sampling point initi-
7. Emergency alarm system.
ating the gas detection system alarm is within
6004.2.2.8.1 Fail-safe engineered systems. Emer- a gas cabinet or exhausted enclosure, the shut-
gency power shall not be required for mechanical off valve in the gas cabinet or exhausted
exhaust ventilation, treatment systems and tempera- enclosure for the specific gas detected shall
ture control systems where approved fail-safe engi- automatically close.
neered systems are installed.
2. Where the gas-detection sampling point initi-
6004.2.2.9 Automatic fire detection system—highly ating the gas detection system alarm is within
toxic compressed gases. An approved automatic fire a gas room and compressed gas containers are
detection system shall be installed in rooms or areas not in gas cabinets or exhausted enclosures,
where highly toxic compressed gases are stored or the shutoff valves on all gas lines for the spe-
used. Activation of the detection system shall sound a cific gas detected shall automatically close.
local alarm. The fire detection system shall comply 3. Where the gas-detection sampling point initi-
with Section 907. ating the gas detection system alarm is within
6004.2.2.10 Gas detection system. A gas detection sys- a piping distribution manifold enclosure, the
tem complying with Section 916 shall be provided to shutoff valve for the compressed container of
detect the presence of gas at or below the PEL or ceiling specific gas detected supplying the manifold
limit of the gas for which detection is provided. The sys- shall automatically close.
tem shall be capable of monitoring the discharge from Exception: Where the gas-detection sampling
the treatment system at or below one-half the IDLH limit point initiating the gas-detection system alarm is
and shall initiate a response in accordance with Sections at a use location or within a gas valve enclosure
6004.2.2.10.1 through 6004.2.2.10.3 if the gas detection of a branch line downstream of a piping distribu-
alarm is activated. tion manifold, the shutoff valve in the gas valve
Exception: A gas detection system is not required enclosure for the branch line located in the piping
for toxic gases when the physiological warning distribution manifold enclosure shall automati-
threshold level for the gas is at a level below the cally close.
accepted PEL for the gas. 6004.3 Outdoor storage and use. The outdoor storage and

6004.2.2.10.1 Alarms. The gas detection system use of highly toxic and toxic compressed gases shall be in
shall initiate a local alarm and transmit a signal to a accordance with Sections 6004.3.1 through 6004.3.4.
constantly attended control station when a short- 6004.3.1 Applicability. The applicability of regulations
term hazard condition is detected. The alarm shall be governing the outdoor storage and use of highly toxic and

2018 INTERNATIONAL FIRE CODE ® 473
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