Manual for Refrigeration Servicing Technicians - UNEP - Division of ...

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Safe Refrigerant Handling
• Never cut or drill into any refrigeration system, without first
removing the refrigerant. The high pressure refrigerant will be
released rapidly and have serious consequences.
• Ensure that all refrigerant is removed from the system and the
pressure has been brought up to atmospheric pressure with
oxygen-free dry nitrogen before disassembling a system.
• When soldering, brazing, or welding on refrigeration lines,
the lines should be continuously purged with low pressure
oxygen-free dry nitrogen. Cylinders, transfer lines and other
equipment used with refrigerants should not be exposed to high
temperature sources, such as welding, brazing and open flames.
• Following work, the system parts should only be pressure tested
with nitrogen.
• Never pressurise systems or vessels containing refrigerants with
air for leak testing or any other purpose.
• Before transferring refrigerant, verify that the hoses are properly
connected to the system and cylinders.
• Open cylinder valves, hose valves and manifold valves slowly
and steadily.
• Verify that the system has been completely evacuated with a
vacuum pump before cutting any lines.
• Before welding or brazing, evacuate the equipment and then
break the vacuum with oxygen free dry nitrogen. Do not perform
any repair on pressurised equipment.
• Whenever using nitrogen cylinders, ensure that the correctly
rated regulator is used, and the setting does not exceed the
maximum working pressure of the system being worked on.
Handling refrigerant cylinders
Refrigerant cylinders tend to be transported widely and subjected to a
variety of conditions. For these reasons it is important to ensure that they
are handled carefully to avoid severe consequences:
• Always store and transport refrigerant cylinders in upright position
to keep the pressure relief valve in contact with the vapour space.
• Do not throw or drop refrigerant cylinders during transportation,
and never permit them to strike each other violently.
• Do not apply direct heat to refrigerant cylinder while charging a
system to maintain inside pressure; a warm water bath should
be used for that purpose.
• Keep the cylinder cap on the cylinder at all times unless the
cylinder is in use.
• When refrigerant is discharged from a cylinder, immediately
weigh the cylinder, and record the weight of the refrigerant
remaining in the cylinder.
• Ensure only regulators and pressure gauges designed for the
particular refrigerant in the cylinder are used, and do not use
different refrigerants in the same regulator or gauges. Never
attempt to repair cylinders or valves.
• Never use a lifting magnet or a sling. A crane may be used when
a safe cradle is provided to hold the cylinders.
• Never use cylinders for any other purpose than to carry refrigerants.
• Never tamper with cylinder valves or pressure relief devices, or
other safety devices.
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