Publicidad
Idiomas disponibles
Idiomas disponibles
Safety Information (continued)
□
Replacement parts shall be in accordance with the manufacturer's
specifications.
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. Repairs 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 these arching 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 shutoff 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 best
practice be followed , since flammability is a consideration.
The following procedure shall be adhered to:
a) safely remove refrigerant following local and national
regulations;
b) purge the circuit with inert gas;
c) evacuate ( optional for A2L);
d) purge with inert gas ( optional for A2L);
e) open the circuit by cutting or brazing;
□
The refrigerant charge shall be recovered into the correct recovery
cylinders if venting is not allowed by local and national codes.
For appliances containing flammable refrigerants, the system
shall be purged with oxygen - free nitrogen to render the
appliance safe for flammable refrigerants. This process might
need to be repeated several times. Compressed air or oxygen
shall not be used for purging refrigerant systems.
□
For appliances containing flammable refrigerants, refrigerants
purging shall be achieved by breaking the vacuum in the system
with oxygen - free nitrogen and continuing to fill until the working
pressure is achieved, then venting to atmosphere, and finally
pulling down to a vacuum (optional for A2L). This process shall
be repeated until no refrigerant is within the system (optional
for A2L). When the final oxygen - free nitrogen charge is used,
the system shall be vented down to atmospheric pressure to
enable work to take place.
□
Ensure that the outlet for the vacuum pump is not close to any
potential ignition sources and that ventilation is available.
13. Charging procedures
□
In addition to conventional charging procedures, the following
requirements shall be followed:
–Ensure that contamination of different refrigerants does not
occur when using charging equipment.
–Hoses or lines shall be as short as possible to minimise the
amount of refrigerant contained in them.
–Cylinders shall be kept up right.
–Ensure that the refrigeration system is earthed prior to
charging the system with refrigerant.
–Label the system when charging is complete (if not already).
–Extreme care shall be taken not to overfill the refrigeration
system.
□
Prior to recharging the system it shall be pressure tested with OFN.
□
The system shall be leak tested on completion of charging but
prior to commissioning.
□
A follow up leak test shall 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 detail.
□
It is recommended good practice that all refrigerants are recovered
safely.
□
Prior to the task being carried out, an oil and refrigerant sample
shall be taken in case analysis is required prior to re-use of
reclaimed refrigerant. It is essential that electrical power is
available before the task is commenced.
a) Become familiar with the equipment and its operation.
b) Isolate system electrically.
c) Before attempting the procedure ensure that:
–Mechanical handling equipment is available, if required,
5
Publicidad
