Because security, protection from vandalism, durability under heavy usage and other considerations are important, the greater strength of Grade 1 locks makes them the suitable choice for demanding applications. Grade 2 products are adequate for lighter duty, such as storage closets or doors where security is less of an issue than simply excluding people in general. They will keep people from walking through a door, but they provide much less protection against deliberate force than Grade 1 products. Typically, Grade 1 locks must meet twice the requirements of Grade 2. In cycle tests for example, a Grade 2 lock need only function for 400,000 cycles, while a Grade 1 lock must meet at least 800,000 cycles.
Some manufacturers regularly test beyond that limit into the millions of cycles.
Even among locks promoted as Grade 1, there can be some differences. For mortise locks, ANSI A156.13 makes distinctions between Grade 1 Operational and Grade 1 Security. The section includes a distinct operational test that encompasses everything from cycling to finish testing of mortise locks. A separate listing covers security grading. When choosing a Grade 1 mortise lock, it is important to know whether the rating given is for security, operational or both.