Nov 072011
 

Reefers: Are they gassed right?

Britain’s Marime and Coastguard Agency has issued an MIN regarding the explosion of compressors on refrigerated containers, reefers, some fatal, following the use of contaminated refrigerant during maintenance.

Says the MCA: “It has been brought to our attention that a small number of incidents have recently occurred where the compressor unit on reefer containers has exploded. The reason for the failure of the compressor units is still unclear but it would appear that the system, after servicing, has been recharged or ‘topped up’ using contaminated gas.

“A number of shipping companies are aware of the issue and are quarantining reefer units that they suspect contain contaminated refrigeration systems”.

UK P&I Club has circulated part of an analysis by Cambridge Refrigeration Technology: “Refrigerated Container refrigeration units should contain polyolester oil and the refrigerant HFC-134a (1,1,1,2-Tetrafluoroethane) and should therefore be incapable of exploding.

“Material recovered from the exploded units have been analysed by a laboratory and have found to be corroded by a chlorinated compound. Traces of alumina (AL2O3) were also found at the sites.

“From the above data we can be reasonably certain that the pyrophoric liquid ( burns in contact with air) to be is trimethyl aluminium (Al2(CH3)6). The explanation is that the system has been contaminated with a counterfeit refrigerant containing methyl chloride (chloromethane, CH3Cl). This gas works as a refrigerant but reacts with the aluminium in the compressor forming trimethyl aluminium, which is a liquid at room temperature”.

A Lloyds Register safety alert warns: “The international community is phasing-out the use of HCFC R-22 refrigerant. This refrigerant is becoming increasingly difficult and costly to obtain. As a result, it has been reported that some service contractors are mixing dissimilar refrigerants in air conditioning and/or refrigeration systems”.

Masters are advised that before loading reefer units, they should ensure that, if the unit has been recently serviced, re-gassed or ‘topped up’, the unit has been inspected to ensure that it is safe to operate.

If the Master has concerns that there is a suspect reefer unit onboard, the shipper and shipping line should be contacted as a matter of urgency to determine the next course of action. The risk of an explosion is only believed to develop when the unit is in operation.

This Notice is directed to Ship-owners, Masters and Container Leasing Companies, but the issue has implications for Port Authorities and companies transporting and packing refrigerated containers whilst on land when the compressor unit is in use.

Any incidents involving such containers should be reported to the MCA  at:

Tel:                            +44 (0) 23 8032 9100
Fax:                           +44 (0) 23 8032 9204
e-mail:                        Dangerous.goods@mcga.gov.uk

 

 

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