U-

UL

abb. Underwriters Laboratories

UL fire resistive container classifications

class 125

n. a group of UL classifications for containers that maintain inside temperatures less than 125 degrees Fahrenheit when exposed to a fire of specific temperature and duration. The times and fire temperatures are:

1/2 hour 1700 degrees F.

1 hour 1700 degrees F.

2 hour 1850 degrees F.

3 hour 1925 degrees F.

4 hour 2000 degrees F.

class 150

n. a group of UL classifications for containers that maintain inside temperatures less than 150 degrees Fahrenheit when exposed to a fire of specific temperature and duration. The times and fire temperatures are:

1/2 hour 1700 degrees F.

1 hour 1700 degrees F.

2 hour 1850 degrees F.

3 hour 1925 degrees F.

4 hour 2000 degrees F.

class 350

n. a group of UL classifications for containers that maintain inside temperatures less than 350 degrees Fahrenheit when exposed to a fire of specific temperature and duration. The times and fire temperatures are:

1/2 hour 1700 degrees F.

1 hour 1700 degrees F.

2 hour 1850 degrees F.

3 hour 1925 degrees F.

4 hour 2000 degrees F.

UL listed

adj. listed in a directory as having passed specific Underwriters Laboratories testing

unassociated change key

n. a change key which is not related directly to a particular master key through the use of certain constant cuts

unassociated master key

n. a master key which does not have change keys related to its combination through the use of constant cuts

uncombinated

adj. 1. of or pertaining to a cylinder which is or is to be supplied without keys, tumblers and springs 2. of or pertaining to a lock, cylinder or key in which the combination has not been set

uncontrolled cross keying

n. a condition in which two or more different keys under different higher level keys operate one cylinder by design; e.g., XAA1 operated by AB, AB1. Note: This condition severely limits the security of the cylinder and the maximum expansion of the system, and often leads to key interchange

unibolt

n. a single plate of steel used in place of individual multiple bolts to lock a safe door

unidirectional cylinder

n. a cylinder whose key can turn in only one direction from the key pull position

USB key

n. a hardware key connected to a USB port