Three dead and hundreds of reefers grounded is the result of impure refrigerant appearing around the world.
After a number of refrigerated shipping containers (reefers) were serviced in Vietnam a number of explosions, and at least three fatalities, led to reefer owners grounding any suspect units until properly checked.
While investigations continue, It is believed that methyl chloride has been cut with R22 and then been sold as R134a to various Asian service companies.
Container company Maersk Line initially informed the World Shipping Council of incidents with four of its reefer containers. Three of these reefer units had exploded resulting in three fatalities, the most recent being an engineer working on a unit in Brazil. The company subsequently grounded approximately 800 reefers while investigations were carried out.
“We have not been able to identify the exact cause of the incidents,” said a company statement, “but we have noted that the units involved have had a gas repair in Vietnam between late March and late April. While it is still too early to conclude, we suspect that during these repairs the gas system may have been contaminated and that this contamination could cause the issues we have seen.”
Another container company, APL Global Refrigerated Trade, believed their units were not at risk but implemented the following measures: certifying that refrigerant used in all its reefer containers meets the specifications of equipment manufacturers; grounding approximately 100 refrigerated boxes for detailed inspection; placing new restrictions on where the containers can undergo refrigerant system repair.
According to reports, at least two other shipping lines reported refrigerated container explosions in 2011. One reportedly identified contaminated refrigerant gas as the cause. Accounts traced the faulty containers to repair vendors in Vietnam where all had undergone maintenance. As a precaution, APL said it has suspended reefer maintenance work in Vietnam.
Even German compressor manufacturer, GEA Bock, has confirmed a similar fake refrigerant responsible for an increasing number of compressor breakdowns appearing.
While it is unknown whether the incidents are linked, GEA Bock Europe has pinpointed bogus refrigerants purporting to be R134a, which they have found to consist mainly of R22, R30, R40 (methyl chloride) and R142b.
Once the most popular refrigerant, until the advent of CFcs in the 1930s, the Bock warning pinpoints methyl chloride’s aggressive nature, dissolving the aluminium body of the compressor and producing trimethyl aluminium “highly inflammable gases which are self-igniting and explosive on contact with air”. It also attacks plastics and damages compressor hoses, warns Bock. Even the oil doesn’t escape the effects: synthetic POE oil is emulsified by the reaction with methyl chloride and splits into its component materials.
While standard tests will identify the counterfeit refrigerant, making the units safe may be more of a problem. As trimethyl aluminium reverts to liquid it will sit in the crankcase of the compressor making access dangerous, requiring either the injection of a reagent to passivate the liquid or the puncturing of the compressor under water and blowing out the explosive material with dry nitrogen.
GEA Bock Europe also warns of a another refrigerant posing as R134a but found to be a cocktail of R134a, R22 and, sometimes, propane. This bogus gas is said to cause problems in hot countries by confusing the temperature/pressure characteristics and reducing the pressure so that, when at standstill, the correct refrigerant fill amount cannot be specified. Likewise, the apparent suction gas superheat of 7K is not real, but the compressor runs completely liquid. The addition of R22 means the oil is no longer transported back to the compressor. GEA Bock also warns that the addition of propane increases the fire risk.