How are fireproof filing cabinets independently tested for their fire ratings?

UL (Underwriters Laboratories) is the primary independent testing body for fireproof filing cabinets in North America. The UL 72 standard for fire cabinets subjects the cabinet to a controlled furnace fire that reaches temperatures simulating a building fire for the rated duration (0.5, 1, 2, or 3 hours). Thermocouples inside the cabinet record interior temperatures throughout the test. Cabinets that keep interior temperatures below the class threshold (350°F for Class 350) throughout the test earn the UL label. OfficeFurniture2go.com only carries UL-tested models — call 1-800-460-0858.