A couple of tests performed by the BHMA are the strength test and the cycle test. The strength test examines how much forcible turning a lock in the locked position can withstand. To be graded, a lock must stay locked after the minimum force has been applied. For example, a grade 1 key in knob must hold up to 300 lb-in and a lever lock must withstand 450 lb-in. A grade 2 key in knob, must hold up to 150 lb-in and a lever must hold up to 225 lb-in. A grade 3 requires a key-in-knob to withstand at least 120 lb-in and a lever lock must withstand at least 180 lb-in.

The cycle test examines how many times the lock can be operated before it fails. A grade 1 lock must complete 800,000 cycles. A grade 2 lock must complete 400,000 cycles. Grade 3 locks must complete at least 200,000 cycles.

Most commercial applications require either grade 1 or grade 2 locking hardware. Grade 1 not only meets commercial building requirements, it also provides the best security available against vandalism and heavy usage. Because of the overall performance of these locks, they are highly recommended for problem areas.

Some products available as grade 1 include, key in knobs, mortise locks, deadbolts, electronic locks or access control hardware. You can usually spot a grade 1 lock by its size because it's usually much larger than a cylindrical lock.

Grade 2 meets light commercial requirements and exceeds residential building requirements. These locks are adequate for lighter duty doors where security is less of an issue. They will stop unauthorized personnel from walking through the door, but will have less of an effect on deliberate force than grade 1 products.

Grade 3 meets residential building requirements by providing standard residential security. This grade of lock should not be used for any commercial application.