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New blast warning on chemical
New blast warning on chemical
Large cargoes of the hazardous chemical hydrated calcium hypochlorite could become thermally unstable, leading to fire or explosion, at temperatures below 308C, significantly lower than the critical temperature outlined in International Maritime Organisation guidelines, consulting scientists J.H. Burgoyne & Partners have warned.
According to the IMO's Dangerous Goods Code, the hydrated form of calcium hypochlorite should be carried away from sources of heat where temperatures of more than 558C may be present for longer than 24 hours.
However, J.H. Burgoyne said experiments had shown that 40kg packages of hydrated calcium hypochlorite, loaded in a 20-foot container could undergo a runaway reaction, which could lead to fire and/or explosion, at below 458C.
It said in a "general alert to the shipping community" that research work on much larger drums of the material, typically containing 200kg of hydrated calcium hypochlorite, was continuing.
However, extrapolating from the results obtained from experiments on the smaller package sizes, a single 200kg drum of the material could become thermally unstable at less than 408C.
A 20-foot container packed with 200kg drums could undergo a thermal runaway at temperatures below 308C.
J.H. Burgoyne said the ambient temperatures of some holds of certain container ships could reach or exceed these levels.
Therefore, hydrated calcium hypochlorite should not be packed in large receptacles unless in a temperature-controlled environment, and should not be carried in the holds of ships.
It added that stowage on deck should be arranged to avoid direct sunlight.
Concern has grown over the carriage of hydrated calcium hypochlorite, and its anhydrous, or dry, counterpart, after the chemical was implicated in a spate of recent casualties.
Calcium hypochlorite is known to have been carried on the CMA Djakarta, the ship that caught fire off Crete last month.
The Salvage Association expressed extreme concern about J.H. Burgoyne's latest findings.
Michael Laurie, manager of cargo loss control and risk management services at the Salvage Association, said underwriters were already very interested in the issues surrounding calcium hypochlorite, and were examining these issues both in the London market and through the International Union of Marine Insurance.
"I think underwriters will now push IMO as much as they can," he said.
An IMO spokesman said that the organisation could not respond to J.H. Burgoyne's findings, and the company would have to present the data through the "appropriate channels".
He said J.H. Burgoyne should take its findings to the UK's Department of the Environment, Transport and the Regions, or to one of the shipping industry organisations.
The findings could then be raised at the next meeting of the IMO's Dangerous Goods Subcommittee, due in early 2000.
A spokeswoman for the UK's Maritime and Coastguard Agency, an executive agency of the Department of the Environment, Transport and the Regions, said the agency was aware of the report.
Andrea FelstedLloyd's Casualty Week, Vol. 317, No. 8, August 20, 1999.