How do fireproof safes work?

Most safes contain three layers of protective materials:

fireproof gypsum sandwich

To make a safe fireproof the materials used need to be non-conductive of heat and incombustible. While steel is incombustible it conducts heat very well. So, a heat isolation or insulation material is often installed between the inner and outer skins.

Some of the isolation materials used could be perlite, wood chips, diatomaceous earth, Portland cement, vermiculite, mica or gypsum. There are also proprietary materials that have been developed to use for this purpose. You usually find these materials used in high end commercial safes. Gypsum, vermiculite and perlite are commonly used in domestic and office safes.

These are naturally occurring minerals that have high thermal resistance and are very light weight. This makes them ideal for using as insulating materials in safes. You have probably seen both materials in your local hardware store as they are used extensively in horticulture to condition soils.

Useful information

What you need to know about buying a safe.
Choosing the right level of fire resistance is one of the questions you need to address before purchasing your new safe. So you need to know the what makes a safe fireproof.


Find this helpful?

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Safe Checklist

What you need to know before you buy.  Find out more.

Home safes

How home safes are made and what to look for when you buy.

How long

How long should my safe last in a fire. Is 30-minutes enough?