The primary standard for locks is UL 437. The requirements cover door locks, locking cylinders, security container key locks, and two-key locks. Underwriters Laboratories defines the different types of locks for which the specification applies.

Specific Requirements for Locks
Door locks and cylinders must be capable of at least 1000 key changes. Security containers must achieve significantly higher security levels, providing at least 1,000,000 differs for any design. Two-key locks require a minimum of 64 guard key changes, and at least 15,000 customer key changes for any design.

Security Container Key-Locks
Specific requirements for locks that are utilized on security containers include:
· Key shall be field changeable;
· The bolt lever must fit snugly on its post and shall be secured tightly;
· The fence face shall be perpendicular to the plane of the tumblers;
· The wheels, tumblers, levers, or pins shall run true, and be at right angles to their mounting post;

Endurance Test
The lock shall function as intended during 10,000 complete cycles of operation at a rate not exceeding 50 cycles per minute; A lock having a changeable core or field-changeable key design shall operate as intended after each of 50 changes of the core or key.