I insulated a tank system on a life cycle tester with a 2 part urethane foam insulation kit. A spark from the torch found it's way down a small gap thru the cover and lit it right up! I dumped a bucket of water on the cover first, then scrambled to remove the cover and put the rest of it out. What a mess! It burned the paint off the machine in that area and it was a real joy cleaning up all the charred stuff.
I would think the flammability ratings have improved a bit since then.
