Here's how we calculate BTUs for safes:
- We take the total amount of fireboard insulation installed in the safe (ceiling, walls, doorjambs and door) and calculate the fireboard's total BTU value (how much heat those layers can take).
- We take the thickness of the steel (body and door) and calculate the total steel's BTU value (how much heat the steel can take).
- We then ADD BOTH TOGETHER and get a TOTAL BTU VALUE for the safe.
- The total BTU value tells us how much heat a safe can take before the inside temperature goes above 350 degrees.
The higher the BTU fire rating, the more heat the safe can take and the longer it will last in a fire.