Fort Knox’s Inferno Shield 90 is tested to keep the inside of the vault under 350 degrees.
C-rated fireboard insulation is used on all six sides and behind the hinges to eliminate hot spots. Heat sensitive expanding fire seal expands to seal around the entire door on all Fort Knox vaults & safes. In addition to the high-grade UL listed fireboard and deep bend box, a dead air space is manufactured into the vault which acts as a thermal barrier, much like a thermal pane window, to give added protection. This design provides fire protection at 1680 degrees in 90 minutes.
This additional fire protection will cause a decrease in the interior capacity of the vault interior, but it is well worth it! Protect your most prized possessions by adding the most valuable vault option, the Reinforced Fire Liner, and have your vault rated at 1680 degrees in 120 minutes.
Fort Knox also offers an optional Reinforced Fire Liner upgrade. You will trade some internal space, but your fire rating will increase to 1680º in 120 minutes.