Idiomas disponibles
Idiomas disponibles
ENG
A N O R D I C B R A N D
10. Detection of flammable refrigerants
Under no circumstances should potential sources of ignition be used when searching for or detecting refrigerant leaks.
Halide torches (or any other detector use naked flames) must not be used.
11. Leak detection methods
The following leak detection methods are deemed acceptable for systems containing flammable refrigerants.
Electronic leak detectors may be used to detect flammable refrigerants, but the sensitivity may not be adequate, or
may need re-calibration. (Detection equipment must 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 must be calibrated to the refrigerant used and the appropriate percentage
of gas (25 % maximum) must be confirmed.
Leak detection fluids are suitable for use with most refrigerants, but the use of detergents containing chlorine
must be avoided as the chlorine may react with the refrigerant and corrode the copper pipework.
If a leak is suspected, all naked flames must be removed / extinguished.
If a leakage of refrigerant is found which requires brazing, all of the refrigerant must be recovered from the system or
isolated (by means of shut-off valves) in a part of the system not affected by the leak. Oxygen- free-nitrogen (OFN)
must then be passed through the system both before and during the brazing process.
12. Removal and evacuation
Conventional procedures must be used when accessing the refrigerant circuit for repairs or any other purpose.
However, it is important that best practice is followed since flammability must be considered. The following procedure
must be adhered to:
• Remove the refrigerant;
• Purge the circuit with inert gas;
• Evacuate the circuit;
• Purge again with inert gas;
• Open the circuit by cutting or brazing.
The refrigerant charge must be recovered into the correct recovery cylinders. The system must be flushed with OFN to
render the unit safe. This process may need to be repeated several times. Compressed air or oxygen must not be used
for this task.
Flushing must be achieved by breaking the vacuum in the system using OFN and continuing to fill until the working
pressure is achieved, then venting to the atmosphere, and finally reducing to a vacuum pressure. This process must
be repeated until there is no refrigerant left in the system. When the final OFN charge is used, the system must be
ventilated to atmospheric pressure to enable work to take place. This operation is absolutely vital if brazing operations
are to take place on the pipework.
Ensure that the power socket for the vacuum pump is not close to any ignition sources and that there is ventilation
available.
13. Charging procedures
In addition to conventional charging procedures, the following requirements must be met.
– Ensure that there is no contamination of different refrigerants when using charging equipment. Hoses or lines must
be as short as possible to minimise the amount of refrigerant contained in them.
– Cylinders must be kept upright.
– Ensure that the refrigeration system is earthed prior to charging the system with refrigerant.
– Label the system when charging is complete (unless it is already labelled).
– Extreme care must be taken not to overfill the refrigeration system.
The system must be pressure-tested using OFN prior to recharging. The system must be tested for leaks on
completion of charging but prior to commissioning. A follow-up leak test must be carried out prior to leaving the site.
14. Decommissioning
Before carrying out this procedure, it is essential that the technician is completely familiar with the equipment and all
its details. It is recommended good practice that all refrigerants are recovered safely. Prior to the task being carried out,
an oil and refrigerant sample must be taken in case analysis is required prior to reuse of reclaimed refrigerant. It is
essential that electricity is available before starting the task.
a) Familiarise yourself with the equipment and its operation.
b) Isolate the system electrically.
c) Before attempting the procedure ensure that:
• Mechanical equipment is available, if required, for handling refrigerant cylinders;
• All personal protective equipment is available and being used correctly;
• The recovery process is supervised at all times by a competent person;
