Lagging fires – A summary of the current knowledge

Lagging fires often occur as a result of a leakage of a liquid from e.g. a pipe or a vessel to its lagging. This work highlights risks associated with this type of fires and proposes mitigative actions. A summary of the current knowledge, based on contacts with representants from the industry and on review of literature, is presented in the present work.

This report is divided into the following sections: introduction (to lagging fires); different types of laggings; knowledge gathering; case studies; detection; and recommendations to mitigate and prevent lagging fires. The section dealing with knowledge gathering is based on statistics from the Swedish Civil Contingencies Agency (MSB), experience from the industry and from literature. The case studies section presents sequencies of events and lessons learned from seven incidents. Three of the case studies occurred in Sweden, while the other four are international case studies identified in the literature. Two of the international incidents resulted in total losses while the worst incidents in Sweden caused loss of production for up to one week.

The current work presents a review of lagging standards, in this work CINI was the only identified organisation having commercial standards describing how lagging fires may be prevented. The current work also presents examples on alternative, company internal, methods on how lagging fires may be mitigated.

In combination with learnings from the industry, from contacts with MSB and from review of literature some indicative factors if a lagging fire will occur have been identified (e.g. type of contaminant or a relationship between flash point and auto ignition temperature). Finally, the report presents different detection methods and their pros and cons.