Fire safes are made of several different materials--both natural and man-made--that are used as insulation between the inner and outer walls. This insulation is resistant to fire or excessive heat. The term "fireproof" is something of a misnomer, because given a high enough temperature virtually everything will burn. But "fireproof" safes are designed to withstand fires a lot longer--and hotter--than the average house blaze.

Perlite

Perlite is a volcanic glass formed by the hydration of obsidian. Perlite is one of the two most common ingredients in fireproof safes as well as doors, cabinets and file drawers. It is very light and relatively inexpensive.

Vermiculite

Vermiculite is the other most common ingredient in fireproof safes. Vermiculite is formed by the hydration of certain basaltic minerals.

Insulite

Insulite is a fireproof insulation material developed and patented by Schwab Corp. It's a proprietary mix, lighter than perlite and vermiculite. It also needs to be chemically cooled after it is poured.

Underwriters Laboratories

Safes made of perlite, vermiculite and Insulite are considered fireproof. They typically come with a Class 350 One Hour Rating from Underwriters Laboratories (UL), the nonprofit company that provides testing standards for fire protection. This rating means the safe will protect paper documents inside it for up to one hour in temperatures reaching 1,700 degrees Fahrenheit. Fires on average burn for just 20 minutes and reach 700 degrees Fahrenheit.

How They Work

Perlite, vermiculite and Insulite all work the same: They release moisture. When used in safes, this moisture cools the air, which lowers the internal temperature and protects the contents of the safe from drying or charring.

Source:

KL Securities

Datalink Associates