What are the UL Ratings for Fire Safes?

Underwriters Laboratory Fire Protection Ratings for Records Protection Equipment

The Underwriters Laboratory (UL) subjects records protection equipment to a barrage of tests to determine it's ability to withstand break ins, explosions, fires and impact tests. The fireproof capability of safes and other records protection equipment is determined by exposing the equipment to extreme temperatures, as much as 2000°F, for extended periods of time. The class rating indicates the maximum internal temperature of the records protection equipment, either 125°F for media and data or 350°F for paper documents. Class ratings are combined with hour ratings to show the minimum duration the product will still maintain a safe internal temperature and humidity level.

Class 125
Media begins to melt at 140°F. The UL Class 125 fire rating indicates the internal temperature of the product will not exceed 125°F with 80% humidity when put through temperatures of at least 1550°F.

Class 350
Paper begins to char at 400°F and has an ignition point of 450°F. The UL Class 350 fire rating indicates the internal temperature of the product will not exceed 350°F with 85% humidity when put through temperatures of at least 1550°F.
These class ratings are used in conjunction with hour ratings ½, 1, 2, 3, or 4:

FR: Fire resistant unrated insulated safe.
1/2 hr: Interior cannot exceed UL Class limits for at least 30 minutes with an outside temperature of 1550°F.
1 hr: Interior cannot exceed UL Class limits for at least 1 hour with an outside temperature of 1700°F.
2 hr: Interior cannot exceed UL Class limits for at least 2 hours with an outside temperature of 1850°F.
3 hr: Interior cannot exceed UL Class limits for at least 3 hours with an outside temperature of 1920°F.
4 hr: Interior cannot exceed UL Class limits for at least 4 hours with an outside temperature of 2000°F.

Learn more about fire safes with UL ratings at http://www.klsecurity.com