3 ms·A fire-proof safe is a safe which won't be destroyed by a fire. That doesn't mean it won't heat up.by Filligree 4y agoA fire-proof safe is a safe which won't be destroyed by a fire. That doesn't mean it won't heat up.netsharc 4y agoThat would violate the laws of thermodynamics... They usually have a rating of how much fire heat they can sustain before the insides get uncomfortable for paper...abofh 4y agoAbout 420 degrees, the question is duration, not temperature.