Isle of Man Ship Registry has issued a Manx Shipping Notice (MSN) to provide guidance to all Isle of Man Registered vessels on the installation and maintenance of oxy-acetylene and refrigeration gas equipment. This MSN replaces Industry Circulars 14 and 20 which are withdrawn.
Gas cylinders containing refrigeration gas and nitrogen are normally sent to the ship full and returned to a service provider when empty. These gases are not corrosive and providing the bottle contains the original gas sent from the supplier (and gas has not been added to the bottle on board) the bottles can be periodically inspected and tested at intervals in accordance with the RID/ADR regulations. In most cases, for refrigeration gases and nitrogen this is at 10 yearly intervals.
The inspection and testing procedure should include:
Checking the cylinder’s internal and external conditions
Checking of threads, valves, service equipment and any other accessories including the pressure relief devices
Carrying out a pressure test
The procedure should be carried out in accordance with one of the following standards (as appropriate, depending upon the type of cylinder) or another internationally recognised equivalent standard:
BS EN 1803:2002 Transportable gas cylinders – Periodic inspection and testing of welded carbon steel gas cylinders
BS EN 1968:2002 Transportable gas cylinders – Periodic inspection and testing of seamless steel gas cylinders
Both of these standards place the emphasis on the service provider to inspect and test the cylinders if they have passed their periodic inspection date. Potentially it is permitted for a service provider to receive a refrigeration bottle at 9.5 years, and not carry out a test before filling the bottle and then sending it to the vessel.
The vessel is not required to return the gas cylinder before the contents have been used even though the test interval period may have lapsed. This is provided the cylinder has been subjected to normal conditions of use and has not been subjected to abusive or abnormal conditions of use rendering the cylinder unsafe, or any gas has been added to the cylinder. After consultation with the industry, the Ship Registry recommends that cylinders which have exceeded their inspection dates should not remain on the vessel more than 5 years after the inspection date, after which time the cylinder should be returned to a service provider for inspection and testing.
Therefore a bottle containing refrigeration gases that has been sent to the vessel could remain on the vessel for a maximum of 15 years before being sent ashore for testing, assuming that it was brand new when sent to the vessel.
Since refrigerant recovery cylinders are normally filled with products of an uncontrolled purity these cylinders should be inspected and tested at a maximum interval of five years. Cylinders containing acetylene or oxygen normally used for welding/gas cutting should be provided with a permanent storage facility. Any new fixed piping installation should be approved by the vessel’s Classification Society and pressure tested to their satisfaction.