Tank Fire

An insulated 400 bbl crude oil tank (API 12F) caught fire yesterday in northern Alberta.  The fire was restricted to the ullage space and the flames were coming from the 10” emergency vent and 3” normal vent.   The company that owned the tank requested that the fire brigade put water to the vent space.  They focused on the 10” emergency vent.  Within seconds of putting water there the tank roof blew.  It flew 75 feet in the air but came safely to earth.  The tank had been on fire for 3 hours prior to this action being taken.  Officials believe that the water spray effectively reduced the exhaust space to what the normal vent’s capacity was and the internal pressure quickly went over allowable limits.  The fire department is expected to distribute a warning not to put water to the emergency vent.