Page 120 - 2018_IFC

BUILDING SERVICES AND SYSTEMS

shall discharge vapor to the atmosphere only through an water shall be prevented from freezing. The discharge pipe
approved treatment system in accordance with Section from the pressure relief device shall distribute ammonia in
605.12.5 or a flaring system in accordance with Section the bottom of the tank, but not lower than 33 feet (10 058
605.12.6. Systems containing more than 6.6 pounds (3 kg) mm) below the maximum liquid level. The tank shall con-
of flammable refrigerants having a density less than the tain the volume of water and ammonia without overflow-
density of air shall be permitted to discharge vapor to the ing.
atmosphere provided that the point of discharge is located
605.13 Mechanical ventilation exhaust. Exhaust from
outside of the structure at not less than 15 feet (4572 mm) mechanical ventilation systems serving refrigeration machin-
above the adjoining grade level and not less than 20 feet ery rooms containing flammable, toxic or highly toxic refrig-
(6096 mm) from any window, ventilation opening or exit.
erants, other than ammonia, capable of exceeding 25 percent
605.12.3 Toxic and highly toxic refrigerants. Systems of the LFL or 50 percent of the IDLH shall be equipped with
containing more than 6.6 pounds (3 kg) of toxic or highly approved treatment systems to reduce the discharge concen-
toxic refrigerants shall discharge vapor to the atmosphere trations to those values or lower.
only through an approved treatment system in accordance Exception: Refrigeration systems containing Group A2L
with Section 605.12.5 or a flaring system in accordance
complying with Section 605.17.
with Section 605.12.6.
605.14 Notification of refrigerant discharges. The fire code
605.12.4 Ammonia refrigerant. Systems containing official shall be notified immediately when a discharge
more than 6.6 pounds (3 kg) of ammonia refrigerant shall becomes reportable under state, federal or local regulations in
discharge vapor to the atmosphere in accordance with one accordance with Section 5003.3.1.
of the following methods:
605.15 Records. A record of refrigerant quantities brought
1. Directly to atmosphere where the fire code official into and removed from the premises shall be maintained.
determines, on review of an engineering analysis
prepared in accordance with Section 104.7.2, that a [M] 605.16 Electrical equipment. Where refrigerant of
fire, health or environmental hazard would not result Groups A2, A3, B2 and B3, as defined in the International
from atmospheric discharge of ammonia. Mechanical Code, are used, refrigeration machinery rooms
shall conform to the Class I, Division 2 hazardous location
2. Through an approved treatment system in accor- classification requirements of NFPA 70.
dance with Section 605.12.5.
Exceptions:
3. Through a flaring system in accordance with Section
605.12.6. 1. Ammonia machinery rooms that are provided with
ventilation in accordance with Section 1106.3 of the
4. Through an approved ammonia diffusion system in
accordance with Section 605.12.7. International Mechanical Code.
5. By other approved means. 2. Machinery rooms for systems containing Group
A2L refrigerants that are provided with ventilation
Exception: Ammonia/water absorption systems con- in accordance with Section 605.17.
taining less than 22 pounds (10 kg) of ammonia and for
which the ammonia circuit is located entirely outdoors. [M] 605.17 Special requirements for Group A2L refriger-
ant machinery rooms. Machinery rooms with systems con-
605.12.5 Treatment systems. Treatment systems shall be
taining Group A2L refrigerants shall comply with Sections
designed to reduce the allowable discharge concentration 605.17.1 through 605.17.3.
of the refrigerant gas to not more than 50 percent of the
IDLH at the point of exhaust. Treatment systems shall be Exception: Machinery rooms conforming to the Class
in accordance with Chapter 60. 1, Division 2 hazardous location classification require-
ments of NFPA 70.
605.12.6 Flaring systems. Flaring systems for incineration
of flammable refrigerants shall be designed to incinerate 605.17.1 Refrigerant detection system. The machinery
the entire discharge. The products of refrigerant incinera- room shall be provided with a refrigerant detection sys-
tion shall not pose health or environmental hazards. Incin- tem. The refrigerant detection system shall be in accor-
eration shall be automatic upon initiation of dis-charge, dance with Section 605.8 and all of the following:
shall be designed to prevent blowback and shall not expose
structures or materials to threat of fire. Standby fuel, such 1. The detectors shall activate at or below a refrigerant
concentration of 25 percent of the LFL.
as LP-gas, and standby power shall have the capacity to
operate for one and one-half the required time for complete 2. Upon activation, the detection system shall activate
incineration of refrigerant in the system. Standby electrical the emergency ventilation system in Section
power, where required to complete the incineration pro- 605.17.3.
cess, shall be in accordance with Section 1203.
3. The detection, signaling and control circuits shall be
605.12.7 Ammonia diffusion systems. Ammonia diffu- supervised.
sion systems shall include a tank containing 1 gallon of
water for each pound of ammonia (8.3 L of water for each [M] 605.17.2 Emergency ventilation system. An emer-
1 kg of ammonia) that will be released in 1 hour from the gency ventilation system shall be provided at the mini-
largest relief device connected to the discharge pipe. The mum exhaust rate specified in ASHRAE 15 or Table

2018 INTERNATIONAL FIRE CODE ® 87
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