U.L. Tests

* Explosion Hazard Test
An empty sample is closed, locked and placed into a furnace preheated to 2000°F. This temperature is maintained for 30 minutes (20 minutes for units rated1/2 hour) and if no explosion results, the unit is allowed to cool without opening the furnace doors. Once cooled, the unit is opened, dismantled and examinations made reguarding the heat insulating properties of the sample such as condition of interior finish, security of interior equipment, lock part fastenings, and any signs of undue transmission of heat or moisture.

**Fire Endurance Tests
After the units' contents are placed inside and in contact with the interior walls, the unit is closed, locked, and exposed to a uniformly distributed fire. The temperature of which is regulated and increased according to the Standard Time Temperature Curve summerized below. The fire is continued for the period required for the classification desired and allowed to cool without opening the furnace. The interior temperature is recorded throughout the test and during the subsequent cooling period until a definite drop is shown and must never exceed 150°F or 350°F as the case may be. Once cooled, the unit is opened, dismantled and its contents examined for usability. The units' locking mechanism and part fastenings are examined for security and the interior examined for any visible evidence of undue heat transmission. Regular production units must again pass the Fire Endurance Test, 1 year after the first test or 1 year after production of the tested unit began.

***Fire & Impact Test
After the units' contents are placed inside and in contact with the interior walls, the unit is closed, locked and exposed to the Standard time as in the Fire Endurance Test for the period of time stated for that classification. Within two minutes, the unit is removed from the furnace and dropped 30' onto a riprap of brick on a heavy concrete base. After impact, the unit is examined for deformation, rupture of parts, damaged insulation, and any other openings into the interior of the unit. When sufficently cooled for handling the unit is inverted, reheated for the time stated and allowed to cool without opening the furnace doors. Once cooled, the unit is opened, dimantled and examinations made reguarding the heat insulating properties of the sample such as uasability of contents, condition of the interior finish, security of locks, part fastenings and any signs of undue transmission of heat or moisture.

****Humidity Test
After pre-conditioning, the unit is heated for 12 hours to obtain an interior temperature of 70+or- 5°F and a relative humidity of 50 +or- 15 percent. The unit must successfully maintain an interior relative humidity less than 85% during that part of the cooling period when the interior temperature is above 120°F. Units are also examined for any signs of moisture penetration into the interior.

*****Combined Explosion Hazard - Impact Test
At the manufacturer's option, both the Fire-Impact Test and the Explosion Hazard Test can be combined and conducted on one sample fire resistant safe or insulated record container as follows. The Explosion Hazard Test is first conducted. If no explosion results during 30 minutes at 2000°F, the furnace temperatures are to be reduced to those of the Standard Test Temperature Curve and the fire continued for an additional 30 minutes for units to be rated 4 Hours, and for an additional 15 minutes for units to be rated 2 Hours. No additional exposure is required for units to be rated 1 Hour. After exposure to the fire for the total period necessary for the classification desired, the furnace fire is to be extinguished and the test sample withdrawn. Within 2 minutes, the unit is dropped from 30' into the riprap of brick on a heavy concrete base, examined, reheated, and re-examined as per the requirements of the Fire And Impact Test.