How does UL test for fire resistance?
The following is an explanation of the Underwriter’s Laboratories’ fire resistant container testing procedures on the Class 350F, one hour and Class 350F two hour Fire Labels. UL Label/Class 350F-one hour and Class 350F-two hour. The safe will maintain an interior temperature less than 350F when exposed to fire for a period of one hour at 1700F or for a period of two hours at 1850F. Safe must successfully undergo all other requirements for the Fire Endurance Test, Explosion Hazard Test and the Fire/Impact Test as stated below.Fire Endurance Test After heat sensors and paper are placed inside the safe, the unit is locked and exposed to a uniformly distributed fire. The furnace is regulated to reach a maximum temperature of 1700F for a period of one hour, or 1850F for two hours, then allowed to cool without opening the furnace. The interior temperature is recorded throughout the test and during the cooling period until a definite drop is shown and must never exceed 350F. Once cooled, the
