the last kitchen fire system class I went to was put on by Amerex. to Get UL Listing, they had to set up a hood/duct system and then set it on fire. the requirement for the amount of grease was 1/4 inch, Heat the fryer to spontaneous combustion, let the system pre-burn for a set time and trip the fire system. The gas was left on for the test. I was told that at times the duct (1/8 inch metal) would change colors, yellow to orange to red to blue and then almost transparent. Gives you an idea of the temps a duct fire can reach. We're talking over 3,000 degrees!
Douglas Hicks
General Fire Equipment Co of Eastern Oregon, Inc
