Recommendations on the Carriage of Calcium Hypochlorite

Reference is made to The International Maritime Organisation’s (IMO) Marine Safety Circular No. 963 dated 1 June 2000.

After several large fires in cargo ships in the 1990? involving calcium hypochlorite, the International Group of P&I Clubs commissioned full-scale tests on the package sizes of this cargo, which are routinely shipped. The results were such that experts advising the International Group viewed the prevailing transport requirements for this product group as inadequate and recommended that they be amended.

The International Group therefore delivered a submission to the February 2000 meeting of the IMO sub-committee on Dangerous Goods, Solid Cargoes and Containers (DSC5), recommending amendments to the IMDG Code transport requirements for calcium hypochlorite. The changes recommended to the IMO were based on the scientific results reflected in the Group circular issued by the Clubs in November 1999. After much debate in plenary session at DSC5 the sub-committee decided to recommend the Maritime Safety Committee to partially amend the rules in the updated version of the IMDG Code (Amendment 30) coming into force 1 January 2001. However, the amendments will not introduce any changes to package sizes for this product, nor will they expressly require stowage of the cargo Clear of Living Quarters. The Maritime Safety Committee (MSC 72) adopted the recommendations of DSC 5 and the entries for calcium hypochlorite (UN Nos. 1748, 2208 and 2880) will be amended in the new version of the code. In addition, an MSC Circular (attached) was issued urging all parties to implement the amended requirements as soon as possible.

The International Group supports the actions undertaken by the IMO and agrees with the amendments introduced in the new IMDG Code. However, the failure to introduce package size limitation and the failure to require stowage Clear of Living Quarters contradicts scientific advice received from the experts advising the International Group. All of the full scale tests performed by the International Group on calcium hypochlorite UN No. 2880 indicates that larger packages can develop a critical condition at temperatures which can be encountered in cargo holds of modern container vessels. Furthermore, if calcium hypochlorite develops a critical condition (for any reason) it will emit chlorine gas, which is toxic, and the runaway reaction will develop extreme heat that will ignite surrounding cargoes, which demonstrates the need to consider the proximity to living quarters in stowage of such cargoes.

Consequently, it is the recommendation of the International Group that Members involved in shipments of calcium hypochlorite products should, in addition to the new requirements of the IMDG Code, ensure that cargo transport units are stowed Clear of Living Quarters and that the size of the individual packages stowed in the cargo transport unit should not exceed 45 kg net weight per package.

Below is a list of synonyms for products that are calcium hypochlorites or products related to calcium hypochlorite. Depending on the exact chemical composition of the product it may or may not become unstable at temperatures encountered in the ship’s hold.

B-K POWDERBLEACHING POWDER
BLEACHING POWDER, containing 39% or less chlorine
CALCIUM CHLOROHYDROCHLORITE
CALCIUM HYPOCHLORIDE
CALCIUM HYPOCHLORITE
CALCIUM OXYCHLORIDE
CAPORIT
CCH
CHLORIDE OF LIME
CHLORINATED LIME
HTH
HY-CHLOR
LIME CHLORIDE

Reference : The International Group of P&I Clubs