Safes are rated as to threat resistance, and typically, the insurable amount of the goods contained in the safe will go higher as the rating increases. The insurance company will require a U.L. rated safe, as described in the following burglary resistance classifications for combination-lock safes (with a possible key lock in addition to the dial).
TL represents a test of tool resistance. These tools would include pressure-applying devices, portable electric drills, common hand tools, grinders, cutting wheels, carbide drill bits, and picking tools. TR represents the resistance to oxy-fuel gas cutting or to a welding torch.
The following is a brief explanation of each safe rating:
TL15: Considered minimum security for portable valuables, this safe has successfully resisted entry for a period of fifteen minutes with the use of the previously mentioned tools.
TL30: Considered much more practical than the TL15 for the safe-keeping of portable valuables. This safe has successfully resisted entry with the use of the above mentioned tools for a period of at least thirty minutes.
TRTL30: This rating will most likely get the insured party a break in premiums and also an allowable higher storage value by an insurance company, due to its higher standard resistance, not only to tools, but to oxy-fuel gas cutting and a welding torch for at least 30 minutes.
TRTL60: This type of safe will again take a jump upward in allowable contained value for insurance purposes. This rated safe has demonstrated a resistance of entry by both tools and gas torches for a period of at least sixty minutes.
TXTL60: The safe of choice for the high-end jewelers and dealers, this rating has not only been tested against tools and torches, but also high explosives. The test is performed with no more than four ounces of nitroglycerin (or the equivalent) per charge. The entire test is limited to eight ounces of nitroglycerin or its equivalent. (Two full charges.)
Entry or failed resistance is defined as follows:
TL15/TL30: Opening the safe door or creating a six square-inch hole completely through the door or front face.
TRTL30/TRTL60/TXTL60: Opening the safe door or creating a two-inch square hole in the door, front face, or any side of the safe.