Worked a fire in a bathroom with a furnace in it. Lady says she was in the bathroom giving daughter a bath and did turn the furnace up. Furnace (natural gas) is properly installed in 1994 in an 1800 era's house that is on the historical society register. The fire originated in the furnace flu-chase which is actually nothing more then the furnace flu running laterally between two 2 x 12 floor support studs then elbows upward and goes through an interior/exterior wall space in the third floor then through roof. The area around where it elbows is decomposed and charred several inches around the pipe. No metal support above or below where it turns up through the floor. This is some eight feet away from the unit. Furnace is fine until you get to where the flu goes through the ceiling. Door to furnace enclosure is burnt off but the paint on the unit is still in good shape with only minor oxidization. The pipe is double wall and proper for the occupancy. No wires in the area. Only damage is along the path of the furnace flu pipe. Shut-in done and furnace was not leaking even though it had been through a fire. Flu not separated anywhere. No indication anything was introduced into the chase and would have been very difficult to do so. Fire occurs 15 minutes after owner and daughter leave the house. So if the long-term heating of wood/pyrolysis theory is debunked (i.e. magnatek) what the hell else is left to cause this fire? What would my esteemed colleagues rule this. No background data to indicate the owner has a motive. Place has been for sale for 4 months but that in and of itself does not equate to a motive.

Dave