Loading ...
Loading ...
Loading ...
5
NOTE:
The use of silicon sealant may inhibit the effectiveness of some types of leak
detection equipment. Intrinsically safe components do not have to be isolated
prior to working on them.
8.Repair to intrinsically safe components
Do not apply any permanent inductive or capacitance loads to the circuit without
ensuring that this will not exceed the permissible voltage and current permitted
for the equipment in use.
Intrinsically safe components are the only types that can be worked on while live
in the presence of a flammable atmosphere. The test apparatus shall be at the
correct rating.
Replace components only with parts specified by the manufacturer.
Other parts may result in the ignition of refrigerant in the atmosphere from a
leak.
9.Cabling
Check that cabling will not be subject to wear, corrosion, excessive pressure,
vibration,sharp edges or any other adverse environmental effects.
The check shall also take into account the effects of aging or continual vibration
from sources such as compressors or fans.
10.Detection of flammable refrigerants
Under no circumstances shall potential sources of ignition be used in the
searching for or detection of refrigerant leaks.
A halide torch (or any other detector using a naked flame) shall not be used.
11. Leak detection methods
The following leak detection methods are deemed acceptable for systems
containing flammable refrigerants:
- Electronic leak detectors shall be used to detect flammable refrigerants, but
the sensitivity may not be adequate, or may need re-calibration. (Detection
equipment shall be calibrated in a refrigerant-free area.)
- Ensure that the detector is not a potential source of ignition and is suitable
for the refrigerant used.
- Leak detection equipment shall be set at a percentage of the LFL of the
refrigerant and shall be calibrated to the refrigerant employed and the
appropriate percentage of gas (25 % maximum) is confirmed.
- Leak detection fluids are suitable for use with most refrigerants but the
use of
detergents containing chlorine shall be avoided as the chlorine may react with
the refrigerant and corrode the copper pipe-work.
- If a leak is suspected, all naked flames shall be removed/ extinguished.
- If a leakage of refrigerant is found which requires brazing, all of the refrigerant
shall be recovered from the system, or isolated (by means of shut off valves) in a
part of the system remote from the leak.
- Oxygen free nitrogen (OFN) shall then be purged through the system both
before and during the brazing process.
12.Removal and evacuation
When breaking into the refrigerant circuit to make repairs – or for any other
purpose – conventional procedures shall be used. However, for flammable
refrigerants it is important that the best practice is followed since flammability is
a consideration. Opening of the refrigeration systems shall not be done by
brazing.
The following procedure shall be adhered to:
- Remove refrigerant;
- Purge the circuit with inert gas;
Loading ...
Loading ...
Loading ...