Grades for deadbolts are established by American National Standards Institute (ANSI) requirements. Grade 3 is recognized as the lowest passing standard, with higher standards being grades 1 and 2.
To qualify as Grade 3, a deadbolt must withstand up to 90 foot-pounds of pressure, and project 5/8 of an inch beyond the door into the receiver.
Testing criterion for Grade 3 deadbolts include tests for resistance against door knob impact, impact against the deadbolt (including different pounds of pressure over varying blow amounts), the bolt's sawing resistance and bolt end pressure tests.
Grade 3 deadbolts are usually found in copper, nickel, brass and other common metals. Occasionally, the faces of Grade 3 bolts will be fashioned of a non-metallic patina.
Most home insurers will offer their own door lock and deadbolt recommendations, and Grade 3 deadbolts rarely meet their minimum standards. Double cylinder deadbolts, and those that extend 1 inch or more beyond the door.
Best Used When
Grade 3 deadbolts are the lowest standard-passing locks, and also therefore usually the cheapest deadbolts available. Grade 3 deadbolts are usually recommended only as supplementary with other lock mechanisms.
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