5.1.2 All
cooling and secondary refrigerant pumps are to be provided with an
indication of discharge pressure and a low discharge pressure alarm
at each control station.
5.1.3 The
power to all independently driven ventilation fans is to be capable
of being stopped from position(s) outside the fire boundary which
will remain readily accessible in the event of fire occurring in any
space, as well as from the local control panel.
5.1.5 Refrigeration
compressors are to be provided with the following instrumentation
and automatic shutdowns:
-
Indication of
suction pressure (saturated temperature), including intermediate stage
when applicable.
-
Indication of
discharge pressure (saturated temperature), including intermediate
stage when applicable.
-
Indication of
lubricating oil pressure.
-
Indication of
cumulative running hours (screw compressors).
-
Automatic shutdown
in the event of low lubricating oil pressure.
-
Automatic shutdown
in the event of high discharge pressure, see also
Pt 7, Ch 15, 5.1 General 5.1.13.
-
Automatic shutdown
in the event of low suction pressure.
5.1.6 For
refrigeration compressors greater than 25 kW, the following instrumentation,
additional to that required by Pt 7, Ch 15, 5.1 General 5.1.5,
is to be provided:
-
Indication of
lubricating oil temperature.
-
Indication of
condenser cooling water outlet temperature.
-
Indication of
cumulative running hours (reciprocating compressors).
-
Indication of
suction and discharge temperatures.
5.1.7 Alarms
are to be initiated in the event of the following fault conditions
with refrigeration compressors:
-
High discharge
pressure.
-
Low suction pressure.
-
Low oil pressure.
-
High discharge
temperature.
-
High oil temperature.
-
Motor shutdown.
5.1.8 Refrigeration
plants are to be provided with the following alarms as applicable:
-
Failure of condenser
cooling water pumps.
-
High condenser
cooling water outlet temperature.
-
Failure of air
cooler fans.
-
High and low
refrigerated air delivery temperatures.
-
High secondary
refrigerant temperatures.
-
Failure of secondary
refrigerant pump.
-
Low level in
secondary refrigerant header tank.
5.1.10 Where
more than one compressor is fitted, the control sequence is to be
such as to allow one machine to stop in the event of a reduction in
cooling duty. Provision is to be made to allow selection of the lead
machine to equalise running hours.
5.1.11 To
allow the equipment to be isolated from the power supply in the event
of a failure or refrigerant leak, refrigeration compressors and AHUs
are to be fitted with local emergency stop switches.
5.1.12 AHUs
are to be provided with the following instrumentation as a minimum:
-
Indication of
primary refrigerant outlet pressure and temperature; and
-
Indication of
outlet air temperature.
5.1.13 Compressors are to be provided with automatic shutdown in the event of high
discharge pressure. For refrigeration systems where the maximum working pressure is less
than or equal to 4 MPa, the automatic shutdown is to operate at a pressure in excess of
normal operating pressure but no greater than 0,9 of the maximum working pressure. For
refrigeration systems where the maximum working pressure is greater than 4 MPa, the
automatic shutdown is to operate at a pressure in excess of normal operating pressure
but no greater than 0,95 of the maximum working pressure.