Technical Guide NPL Acoustics 2004/1
Interim Document for the Periodic Testing of IEC 61672 Sound Level Meters (Edition 2)

The first two parts of the new international specification standard for sound level meters, IEC 61672, have now been published. These cover the specifications and pattern evaluation tests for new models of sound level meter. However, Part 3 of the standard on periodic testing is still in preparation within IEC.

As sound level meters manufactured to this new standard are becoming available on the market, there is an immediate need for a document to cover periodic testing, as BS 7580, the current British Standard for periodic verification, does not apply to instruments manufactured to IEC 61672.

This technical guide has therefore been produced as an interim document, for use in the UK, for the periodic verification of sound level meters originally manufactured to IEC 61672-1 : 2002 (BS EN 61672-1 : 2003), until Part 3 of IEC 61672 is published.

Edition 2 of the Technical Guide, published in February 2005, includes minor modifications to the original text. These changes reflect the fact that some required adjustment data and/or uncertainties data may not yet be available from the manufacturer or supplier of the sound level meter. Where this is the case, Edition 2 gives information on how the calibration laboratory should proceed with the tests.

It has been prepared by a sub-group of the United Kingdom Accreditation Service's (UKAS) Acoustical Industry Technical Committee, in response to requests for an interim document to be made available for use by accredited laboratories. UKAS's Technical Policy Statement TPS 49 advises laboratories and assessors on these interim arrangements.

The technical guide will be withdrawn 6 months after the publication of the BS EN equivalent of IEC 61672 Part 3.