The UL 72 Fire Test

UL logoThe Underwriters Laboratory (UL for short) is an American organization that independently tests and certifies products according to rigorous safety standards. Their fire resistance tests for record keeping products such as filing cabinets are very well regarded and are typically referred to as the UL 72 test.

Like the NT FIRE 017, the UL 72 has several different variations depending on what contents the filing cabinet must protect and how long it must protect them for.

The test is performed by fitting highly advanced thermometers inside the filing cabinet. The cabinet is then placed in a furnace and heated to temperatures of around 1000° Celsius. After a set amount of time, the furnace is extinguished. While the cabinet cools, it remains under monitoring as heat levels can rise in the interior even after the fire is put out.

The UL 72 Class 350 is perhaps the most common rating. Cabinets in this category will protect paper for 30 minutes, 60 minutes or 120 minutes (the time will be given as part of the rating). The temperature in the cabinet must not go above 350° F (approximately 177° C).

Cabinets designated UL 72 Class 150 will protect typical computer data products such as hard drives and CDs. They will also protect photographic records. To pass this test, the cabinet must maintain an internal temperature below 150° F (around 65° C), as well as a humidity level below 85%.

The most stringent test is the UL 72 Class 125. This test is for cabinets meant to protect extremely fragile data media such as floppy disks. The internal temperature in the cabinet must not rise above 125° F (around 55° C) and humidity must not reach above 80%.

Certain types of storage unit and filing cabinet might also be subjected to the UL 72 Explosion Hazard Test. This involves placing a cabinet in a furnace that has been preheated to over 1000° C. It is left there for 30 minutes. If this rapid heating causes the cabinet to rupture or explode, it fails the test.

Other products might also be subjected to a Fire Impact Test. This simulates a building collapse, a common occurrence during major fires. The cabinet is heated in a furnace, then removed and dropped from a height of around 9 metres onto a bed of rubble. Afterwards, it is returned to the furnace.

The rating on a cabinet will usually indicate which of these tests the cabinet has passed (e.g. Fire and Impact Rated, etc.).

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