This Part of EN 61672 describes procedures for periodic testing of class 1 or class 2 conventional, integrating-averaging, and integrating sound level meters. The aim of the standard is to ensure that periodic testing is performed in a consistent manner by all testing laboratories. The scope of the testing in this standard is deliberately restricted to the minimum considered necessary for periodic tests. Periodic tests described in this standard apply to sound level meters for which the model has, or has not, been pattern approved by an independent testing organization responsible for pattern approvals and in accordance with the test procedures of IEC 61672-2:2003. Because of the limited number and extent of the periodic tests, if evidence of pattern approval is not publicly available no general conclusion about conformance to the requirements of IEC 61672-1:2002 can be made, even if the results of the periodic tests conform to all applicable requirements of this standard.