GUIDANCE FOR THE PREVENTION OF ROLLOVER IN LNG SHIPS

This guidance was produced by SIGTTO to members' concerns about the some of the interpretations of the functional requirements for emergency shutdown systems; in particular, differences between the needs of the liquid natural gases industry and those of liquid petroleum gases industry. It was also aimed to encourage and promote the use of linked emergency shutdown systems at both LPG and LNG terminals, especially where cargo transfer rates are quite high or where they handle one of the cargoes stated in IGC Code 1993/Chapter 17.

However, this SIGTTO publication is not intended to contradict any international or national requirements or standards for operational practices at the liquefied gas ship-shore interface. One of the primary objectives of this guidance was to advise the operators/owners of gas carriers about the rollover-related issues. The rollover itself mainly refers to the quick release if the LNG vapor occurring when the layers of different densities of LNG are spontaneously mixed in a cargo or storage tank. While for the conventional onshore terminals all such issues are known and understood, for LNG vessels the associated circumstances are a bit unusual and have to be paid serious additional attention...