How Safe Is a Fireproof Box in an Attic?

Ratings

• Fire safes are rated according to how long they can keep the interior at a safe temperature while in a typical fire. United Laboratories gives a half-hour rating to a fireproof box that will protect paper documents for at least 30 minutes in typical house fire temperatures. This is enough to protect paper documents but not computer media. Fire safes intended for safe storage of tapes, CDs and other electronic media must meet higher standards.

Media Protection

• ETL Semko's half-hour rating is based on exposure to a 1550 degree Fahrenheit external temperature for 30 minutes. To pass ETL's test, the fire safe must keep the internal temperature low enough to protect computer and audiovisual media. Higher-quality safes rated at one hour, two hours and three hours are commonly available. Not all fireproof safes are also waterproof, and only some are explosion proof. Consult the manufacturer's manual for the exact ratings.

Conditions

• The heat exposure a fireproof safe will receive in a disastrous house fire will depend upon location as well as the duration of the blaze. In an attic surrounded by combustible materials, the fire-resistant box will be fully exposed to heat during a house fire. On a lower floor or in a basement, the safe would not be subject to the full intensity of the blaze. Location is much more important if the fire safe has only a half-hour rating. Put the fire safe on the lowest floor of the building for the best protection and the least exposure.

Effectiveness

• Field tests of several models of fire safes by KSL-5 TV News of Salt Lake City, Utah, showed that the fireproof boxes did well when engulfed by the flames of blazing bales of hay for 5 minutes. The contents of one safe showed some scorching after that brief exposure. CDs and videos used in the tests were said to be undamaged. A typical firesafe warranty provides for replacement of the safe itself if defective but does not insure the contents against fire damage.

Storage Items

• Fireproof boxes are not equally suited to the protection of all valuables. Paper documents need the least protection and will not be damaged by internal temperatures of 350 degrees. CDs, DVDs and flash media will survive at temperatures up to 125 degrees. A fire safe that provides that level of protection may not be enough to safeguard more vulnerable items like video cassettes, film negatives and floppy discs.