Explosion of refrigerated container compression units and recommendations for recharging - Applicability: Container ship operators and crew, container terminals and stevedores, road haulage firms, maintenance fitters and end users/leasers of refrigerated containers.
There have recently been a number of incidents, some fatal, involving explosion of the compressor units fitted to refrigerated (reefer) containers. The cause of the explosions is still under investigation but it appears that the servicing of the refrigeration system is a common factor in each case. It has been reported to Lloyd's Register that refrigerant gas in refrigeration and air conditioning plants is being recharged or ‘topped up’ with different types of gas. This may have been a contributing factor to the explosions. 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. This practice carries the following significant risks:
1. It may violate several European and national standards, and may be illegal in some countries.
2. The unknown composition of the resultant refrigerant mixture may change system performance unexpectedly.
3. Standard pressure gauges and pressure / temperature charts may no longer be used effectively, preventing effective servicing of the equipment.
4. The mixed refrigerant cannot be reclaimed and must be destroyed at considerable cost to the contractor or the equipment owner.
5. Compressor warranties may be invalidated.
6. Safety may be compromised since the Material Safety Data Sheet (MSDS) for the original refrigerant is no longer valid and does not exist for the mixed refrigerant blend of unknown composition.
Lloyd's Register recommendations:
We recommend the following actions when recharging or ‘topping up’ refrigerant systems:
1. Never mix refrigerants of different types with different ASHRAE numbers in the same system.
2. Only ‘top up’ refrigerant in any installed system with refrigerant of the same type and ASHRAE number.
3. Clearly label all systems to prevent accidental mixing of different refrigerants.
4. If accidental mixing does occur, remove the entire refrigerant charge immediately and dispose of it properly, in accordance with relevant national laws.
The Maritime and Coastguard Agency (MCA) has also issued a Marine Information Note on the subject.