A few hints for fire protection:
The main material used in fire walls is gypsum, specifically gypsum-dry-wall. The reason is that gypsum binds to fairly large quantities of water. Water that has to be heated and boiled off before the material will exceed 212F.

You can use this to good effect by creating a poor man's fire resistant file safe. In essence you create a book out of pieces of drywall and place the documents you wish to protect flat between the pieces of drywall. The more layers, and the thicker the drywall, the better the protection. A key consideration is that your drywall book should be placed flat and on a surface that will not shift in a fire so it won't fall open in the fire.

Flat on a concrete slab that is poured on the ground is ideal. You get a triple benefit; the slab is as low as you can go and heat rises, slabs are unlikely to shift in a fire, concrete slabs tend to be cool and a good heat-sink.

Gypsum comes in another form that people forget, plaster-of-Paris. You can make your own heat resistant container by arranging two steel boxes, one inside the other, and filling the space between with liquid plaster and letting it set up. The thicker the plaster the longer the protection lasts in a fire.