along with the ambient temperature to which the system is exposed. Final
test pressures of the second stage shall be maintained on the system for a
minimum of 24 hours. At the end of the 24 hour period, the system pressure
will be recorded along with the ambient temperature to which the system is
exposed. A correction factor of 2 kPa (0.3 psi) 0.3 psi will be allowed
for each degree C (F) F change between test space initial and final ambient
temperature, plus for increase and minus for a decrease. If the corrected
system pressure is not exactly equal to the initial system test pressure,
then the system shall be investigated for leaking joints. To repair leaks,
the joint shall be taken apart, thoroughly cleaned, and reconstructed as a
new joint. Joints repaired by caulking, remelting, or back-welding/brazing
shall not be acceptable. Following repair, the entire system shall be
retested using the pneumatic tests described above. The entire system
shall be reassembled once the pneumatic tests are satisfactorily completed.
3.3.3
Evacuation Test
Following satisfactory completion of the pneumatic tests, the pressure
shall be relieved and the entire system shall be evacuated to an absolute
pressure of 300 micrometers. During evacuation of the system, the ambient
temperature shall be higher than 2 degrees C 35 degrees F. No more than
one system shall be evacuated at one time by one vacuum pump. Once the
desired vacuum has been reached, the vacuum line shall be closed and the
system shall stand for 1 hour. If the pressure rises over 500 micrometers
after the 1 hour period, then the system shall be evacuated again down to
300 micrometers and let set for another 1 hour period. The system shall
not be charged until a vacuum of at least 500 micrometers is maintained for
a period of 1 hour without the assistance of a vacuum line. If during the
testing the pressure continues to rise, check the system for leaks, repair
as required, and repeat the evacuation procedure. During evacuation,
pressures shall be recorded by a thermocouple-type, electronic-type, or a
calibrated-micrometer type gauge.
3.3.4
System Charging and Startup Test
Following satisfactory completion of the evacuation tests, the system shall
be charged with the required amount of refrigerant by raising pressure to
normal operating pressure and in accordance with manufacturer's procedures.
Following charging, the system shall operate with high-side and low-side
pressures and corresponding refrigerant temperatures, at design or improved
values. The entire system shall be tested for leaks. Fluorocarbon systems
shall be tested with halide torch or electronic leak detectors.
3.3.5
Refrigerant Leakage
If a refrigerant leak is discovered after the system has been charged, the
leaking portion of the system shall immediately be isolated from the
remainder of the system and the refrigerant pumped into the system receiver
or other suitable container. Under no circumstances shall the refrigerant
be discharged into the atmosphere.
3.3.6
Contractor's Responsibility
The Contractor shall, at all times during the installation and testing of
the refrigeration system, take steps to prevent the release of refrigerants
into the atmosphere. The steps shall include, but not be limited to,
procedures which will minimize the release of refrigerants to the
atmosphere and the use of refrigerant recovery devices to remove
refrigerant from the system and store the refrigerant for reuse or reclaim.
SECTION 15182
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