Page 505 - 2018_IFC

HIGHLY TOXIC AND TOXIC MATERIALS

sure due to fire exposure are not required to be 2. Toxic gases—use. Treatment systems are not
vented to a treatment system provided that: required for toxic gases supplied by cylinders
or portable tanks not exceeding 1,700 pounds
1. The material in the tank is not flammable.
(772 kg) water capacity where a gas detection
2. The tank is not located in a diked area system complying with Section 6004.2.2.10
with other tanks containing combustible and listed or approved automatic-closing fail-
materials. safe valves are provided. The gas detection
3. The tank is located not less than 30 feet system shall have a sensing interval not
(9144 mm) from combustible materials exceeding 5 minutes. Automatic-closing fail-
or structures or is shielded by a fire bar- safe valves shall be located immediately adja-
rier complying with Section cent to cylinder valves and shall close when
6004.3.2.1.1. gas is detected at the permissible exposure
limit (PEL) by a gas sensor monitoring the
2. Filling or dispensing connections shall be pro-
vided with a means of local exhaust. Such exhaust system at the point of discharge from
exhaust shall be designed to capture fumes and the gas cabinet, exhausted enclosure, venti-
vapors. The exhaust shall be directed to a treat- lated enclosure or gas room.
ment system in accordance with Section 6004.2.2.7.1 Design. Treatment systems shall be
6004.2.2.7. capable of diluting, adsorbing, absorbing, contain-
ing, neutralizing, burning or otherwise processing
3. Stationary tanks shall be provided with a means
of excess flow control on all tank inlet or outlet the contents of the largest single vessel of com-
connections. pressed gas. Where a total containment system is
used, the system shall be designed to handle the
Exceptions: maximum anticipated pressure of release to the sys-
1. Inlet connections designed to prevent tem when it reaches equilibrium.
backflow. 6004.2.2.7.2 Performance. Treatment systems shall
2. Pressure relief devices. be designed to reduce the maximum allowable dis-
charge concentrations of the gas to one-half immedi-
6004.2.2.6 Gas rooms. Gas rooms shall comply with ate by dangerous to life and health (IDLH) at the
Section 5003.8.4 and both of the following require- point of discharge to the atmosphere. Where more
ments:
than one gas is emitted to the treatment system, the
1. The exhaust ventilation from gas rooms shall be treatment system shall be designed to handle the
directed to an exhaust system. worst-case release based on the release rate, the
2. Gas rooms shall be equipped with an approved quantity and the IDLH for all compressed gases
automatic sprinkler system. Alternative fire- stored or used.
extinguishing systems shall not be used. 6004.2.2.7.3 Sizing. Treatment systems shall be
6004.2.2.7 Treatment systems. The exhaust ventila- sized to process the maximum worst-case release
tion from gas cabinets, exhausted enclosures and gas of gas based on the maximum flow rate of release
rooms, and local exhaust systems required in Sections from the largest vessel utilized. The entire contents
6004.2.2.4 and 6004.2.2.5 shall be directed to a treat- of the largest compressed gas vessel shall be con-
ment system. The treatment system shall be utilized to sidered.
handle the accidental release of gas and to process 6004.2.2.7.4 Stationary tanks. Stationary tanks
exhaust ventilation. The treatment system shall be shall be labeled with the maximum rate of release
designed in accordance with Sections 6004.2.2.7.1 for the compressed gas contained based on valves or
through 6004.2.2.7.5 and Section 510 of the Interna- fittings that are inserted directly into the tank. Where
tional Mechanical Code. multiple valves or fittings are provided, the maxi-
Exceptions: mum flow rate of release for valves or fittings with
the highest flow rate shall be indicated. Where lique-
1. Highly toxic and toxic gases—storage. A fied compressed gases are in contact with valves or
treatment system is not required for cylinders, fittings, the liquid flow rate shall be utilized for
containers and tanks in storage where all of computation purposes. Flow rates indicated on the
the following controls are provided:
label shall be converted to cubic feet per minute
3
1.1. Valve outlets are equipped with gas- (cfm/min) (m /s) of gas at normal temperature and
tight outlet plugs or caps. pressure (NTP).
1.2. Handwheel-operated valves have han- 6004.2.2.7.5 Portable tanks and cylinders. The
dles secured to prevent movement. maximum flow rate of release for portable tanks and
cylinders shall be calculated based on the total
1.3. Approved containment vessels or con-
tainment systems are provided in release from the cylinder or tank within the time
specified in Table 6004.2.2.7.5. Where portable
accordance with Section 6004.2.2.3.

472 2018 INTERNATIONAL FIRE CODE ®
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