1101.1 "Prohibited Connections" The uses of
potable water as an open loop, single pass heat exchange fluid for the
refrigeration cycle of HVAC equipment is prohibited.
Delete IMC section 1105.3 and substitute the
following:
1105.3
Refrigerant detector: Machinery rooms shall contain a refrigerant detector with
an audible and visual alarm. The detector, or a sampling tube that draws air to
the detector, shall be located in an area where refrigerant from leak will
concentrate. The alarm shall be actuated at value not greater than the
corresponding TLV-TWA values shown for the refrigerant classification.
Detectors and alarms shall be placed in approved
locations.
Delete IMC section 1105.3 and substitute the
following:
1105.9 Emergency
pressure control system. Refrigeration systems containing more than 6.6 pounds
(93kg) of flammable, toxic or highly toxic refrigerant or ammonia shall be
equipped with an emergency pressure control system in accordance with sections
1105.8.1.1 and 1105.8.2.
1105.9.1 Automatic
crossover valves. Each high and intermediate pressure zone in a refrigeration
system shall be provided with a single automatic valve providing a crossover
connection to a lower pressure zone. Automatic crossover valves shall comply
with sections 1105.8.1.1 through 1105.8.1.3.
1105.9.1.1 Overpressure light setpoint.
Automatic crossover valves shall be arranged to automatically relieve excess
system pressure to a lower pressure zone if the pressure in a high-or
intermediate-pressure zone rises to within fifteen (15) psi (108.4 kPa) of the
setpoint for emergency pressure-relief devices.
1105.9.1.2 Manual operation. When required by
the fire code official, automatic crossover valves shall be capable of manual
operation.
1105.9.1.3 System design
pressure. Refrigeration system zones are connected to a higher-pressure zone by
an automatic crossover valve shall be designed to safely contain the maximum
pressure that can be achieved by interconnection of the two (2)
zones.
1105.9.2 Automatic
emergency stop. An automatic emergency stop feature shall be provided in
accordance with section 1105.9.2.1 and 1105.9.2.2
1105.9.2.1 Operation of an automatic
crossover valve. Operation of an automatic crossover valve shall cause all
compressors on the effected system to immediately stop. Dedicated
pressure-sensing devices located immediately adjacent to crossover valves shall
be permitted as a means for determining operation of a valve. To ensure that
the automatic crossover valve system provides a redundant means of stopping
compressors in an over pressure condition, high-pressure cutout sensors
associated with compressors shall not be used as a basis for determining
operation of a crossover valve.
1105.9.2.2 Overpressure in low-pressure zone.
The lowest pressure zone in a refrigeration system shall be provided with a
dedicated means of determining a rise in system pressure to within fifteen (15)
psi (103.4 kPa) of the setpoint for emergency pressure-relief devices.
Activation of the overpressure sensing device shall cause all compressors on
the effected system to immediately stop.