I have been on the end of a dry chemical extinguisher it isn't fun but I also have been in a space that sprinklers went off in and that isn't either. The best is not to need either and check for faults before fire starts. Inspection, fail safes, GFIs.

The other thing I though of is not to use lamp cord with flexwatt it simply is not made to take the loads that flexwatt can draw. I use heater cord it is easier to work with and has much higher ratings.

I have seen old tech info from Calorique that stated flexwatt should not be run for prolong periods at over 95ºF I don't know if that still applies or not. But I personally have always followed that and never set it higher.