I was told of a true story by the fire chief of our local fire department, you all may really enjoy it. There was a rather small strip mall here in Pennsylvania. Maybe about 10 stores, all on one floor. A small fire had broken out in the electrical room, after hours. The only person working was one security guard. When the fire department got there, and put out the fire, they found 4 fire extinguishers laying on the floor about the room un-used. The security man said that they all must have been faulty. He said he pulled the pins, counted and threw them and none of them went off!!! Apparently he assumed they worked just like a grenade!!