This Standard establishes requirements for Interconnected Locks and includes operational tests@ strength tests@ security tests@ cycle tests@ finish tests and dimensional criteria. Tests described in this Standard are performed under laboratory conditions. In actual usage@ results vary because of installation@ maintenance and environmental conditions. When interconnected locks are used in fire door assemblies@ they shall have been tested and listed for use in fire doors by a nationally recognized independent testing laboratory and shall be under an in-plant follow-up inspection service. Grade Qualifications (Also See Appendix A.) Three classifications of tests are described in this Standard: Operational@ Strength and Security Test. Manufacturers shall indicate the Grade level of their locks. Locks shall meet Operational Tests 9@ Strength Tests 10@ and Security Tests 12 for their grade listing classifications. A Grade 1 lock shall meet all Grade 1 criteria@ a Grade 2 lock shall meet all Grade 2 criteria@ and a Grade 3 lock shall meet all Grade 3 criteria in each classification.