9
10. 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 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, 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;
• recovery equipment and cylinders conform
to the appropriate standards.
d) Pump down refrigerant system, if
possible.
e) If a vacuum is not possible, make a
manifold so that refrigerant can be
removed from various parts of the system.
f) Make sure that cylinder is situated on the
scales before recovery takes place.
g) Start the recovery machine and operate
in accordance with manufacturer’s
instructions.
h) Do not over fi ll cylinders. (No more than
80 % volume liquid charge).
i) Do not exceed the maximum working
pressure of the cylinder, even temporarily.
j) When the cylinders have been fi lled
correctly and the process completed, make
sure that the cylinders and the equipment
are removed from site promptly and all
isolation valves on the equipment are
closed off.
k) Recovered refrigerant shall not be
charged into another refrigeration system
unless it has been cleaned and checked.
• Electrostatic charge may accumulate and
create a hazardous condition when charging
or discharging the refrigerant.
To avoid fi re or explosion, dissipate static
electricity during transfer by grounding and
bonding containers and equipment before
charging/discharging.
11. Labelling
• Equipment shall be labelled stating that it
has been de-commissioned and emptied of
refrigerant.
• The label shall be dated and signed.
• Ensure that there are labels on the
equipment stating the equipment contains
fl ammable refrigerant.
12. Recovery
• When removing refrigerant from a system,
either for servicing or decommissioning,
it is recommended good practice that all
refrigerants are removed safely.
• When transferring refrigerant into cylinders,
ensure that only appropriate refrigerant
recovery cylinders are employed.
• Ensure that the correct number of cylinders
for holding the total system charge are
available.
• All cylinders to be used are designated for
the recovered refrigerant and labelled for
that refrigerant (i.e. special cylinders for the
recovery of refrigerant).
• Cylinders shall be complete with pressure
relief valve and associated shut-off valves in
good working order.
• Recovery cylinders are evacuated and, if
possible, cooled before recovery occurs.
• The recovery equipment shall be in good
working order with a set of instructions
concerning the equipment that is at hand
and shall be suitable for the recovery of
fl ammable refrigerants.
• In addition, a set of calibrated weighing
scales shall be available and in good
working order.
• Hoses shall be complete with leak-free
disconnect couplings and in good condition.
• Before using the recovery machine, check
that it is in satisfactory working order, has
been properly maintained and that any
associated electrical components are
sealed to prevent ignition in the event of a
refrigerant release.
Consult manufacturer if in doubt.
• The recovered refrigerant shall be returned
to the refrigerant supplier in the correct
recovery cylinder, and the relevant Waste
Transfer Note arranged.
• Do not mix refrigerants in recovery units and
especially not in cylinders.
• If compressors or compressor oils are to
be removed, ensure that they have been
evacuated to an acceptable level to make
certain that fl ammable refrigerant does not
remain within the lubricant.
• The evacuation process shall be carried
out prior to returning the compressor to the
suppliers.
• Only electric heating to the compressor
body shall be employed to accelerate this
process.
• When oil is drained from a system, it shall be
carried out safely.
8
4. 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 fl ammable atmosphere.
• The test apparatus shall be at the correct
rating.
• Replace components only with parts
specifi ed by the manufacturer. Unspecifi ed
parts by manufacturer may result ignition of
refrigerant in the atmosphere from a leak.
5. 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.
6. Detection of fl ammable refrigerants
• Under no circumstances shall potential
sources of ignition be used in the searching
or detection of refrigerant leaks.
• A halide torch (or any other detector using a
naked fl ame) shall not be used.
7. Leak detection methods
• Electronic leak detectors shall be used
to detect fl ammable 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 confi rmed.
• Leak detection fl uids 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 fl ames 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.
8. Removal and evacuation
• When breaking into the refrigerant circuit to make
repairs – or for any other purpose – conventional
procedures shall be used.
However, it is important that best practice is
followed since fl ammability is a consideration.
The following procedure shall be adhered to:
remove refrigerant -> purge the circuit with inert
gas -> evacuate -> purge again with inert gas ->
open the circuit by cutting or brazing
• The refrigerant charge shall be recovered into
the correct recovery cylinders.
• The system shall be “fl ushed” with OFN to
render the unit safe.
• This process may need to be repeated several times.
• Compressed air or oxygen shall not be used
for this task.
• Flushing shall be achieved by breaking the
vacuum in the system with OFN and continuing
to fi ll until the working pressure is achieved,
then venting to atmosphere, and fi nally pulling
down to a vacuum.
• This process shall be repeated until no
refrigerant is within the system.
• When the fi nal OFN charge is used, the system
shall be vented down to atmospheric pressure
to enable work to take place.
• This operation is absolutely vital if brazing
operations on the pipe work are to take place.
• Ensure that the outlet for the vacuum pump is
not close to any ignition sources and there is
ventilation available.
9. 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
minimize the amount of refrigerant contained
in them.
- Cylinders shall be kept upright.
- 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 over fi ll the
refrigeration system.
• Prior to recharging the system it shall be
pressure tested with OFN (refer to #7).
• 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.
• Electrostatic charge may accumulate and
create a hazardous condition when charging
and discharging the refrigerant.
To avoid fi re or explosion, dissipate static
electricity during transfer by grounding and
bonding containers and equipment before
charging/discharging.
Safety precautions
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