Engine room fires – Appropriate use of insulating material on hot surfaces

Safety flash 10/05 reported on a recent Engine room fire. It was noted in that safety flash that the probable cause of the fire was spraying of leaking hydraulic oil onto an improperly insulated exhaust flange. (NB SOLAS regulations require proper insulation of all surfaces with temperatures above 220°C.)

A member has provided some useful feedback on the incident report, set out below for further information:

• Covering every hot surface with lagging could increase the risk of fire if done so without using suitable insulation material;
• The use of soft or absorbent lagging can create further potential risk, since oil sprayed onto absorbent or soft lagging on a hot exhaust can eventually ignite;
• A small leak might dribble unnoticed onto soft or absorbent lagging until there is enough oil in close proximity to the hot exhaust to cause a fire. This can be an issue with certain widely used makes of engine;
• Oil resistant laggings are commercially available. Whilst these are not perfect, they do afford some protection from oil spray or leaks. These oil-resistant lagging types have a silver facing to protect against flammable liquids.