Describes instruments for the measurement of frequency weighted and time averaged sound pressure levels. Optionally, sound exposure levels may be measured. Specifies additional characteristics to those in AS 1259.1 which are necessary to measure the equivalent continuous sound pressure level (Leq) of steady, intermittent, fluctuating and impulsive sounds. Identical with and reproduced from IEC 804.

This standard describes instruments for the measurement of frequency weighted and time averaged sound pressure levels. Optionally, sound exposure levels may be measured. This standard is consistent with the relevant requirements of IEC Publication 651: Sound Level Meters, but specifies additional characteristics which are necessary to measure the equivalent continuous sound pressure level, Leq, of steady, intermittent, fluctuating and impulsive sounds.Note. - Standardization of an instrument for the measurement of the equivalent continuous sound pressure level and optionally the sound exposure level does not imply that these quantities completely characterize the psychological and physiological effects of sound on man.Though a complete integrating sound level meter is specified, the combination of a conventional sound level meter that satisfies IEC Publication 651 and an accessory or "plug-in" that provides the averaging capability is admissible if the complete system satisfies this standard.The instrument is called "integrating-averaging sound level meter", but the short form "integrating sound level meter" or "averaging sound level meter" may also be used. In this standard, "integrating sound level meter" is used.There are some important differences between the time averaging characteristics of an integrating sound level meter and those of a conventional sound level meter. These differences are discussed in Appendix A.This standard specifies integrating sound level meters of four degrees of accuracy, designated Types 0,1, 2 and 3.For each type, the specification for directional characteristics and frequency weighting and amplifier characteristics are identical to those of IEC Publication 651. Averaging and indicator specifications differ from IEC Publication 651 and it should be noted that they are identical for Types 2 and 3 instruments.The mark "R" on the instrument, if any, indicates that this instrument is calibrated for diffuse field (see Sub-clauses 2.3.3 and 9.1).This standard specifies the following characteristics and test methods for integrating sound level meters: a) integrating and averaging characteristics; b) indicator characteristics; c) overload sensing and indicating characteristics.Integrating sound level meters shall also comply with the requirements in IEC Publication 651 as follows:a) directional characteristics b) frequency weighting characteristics c) sensitivity to various environmentsThe specifications for Types 0, 1, 2 and 3 integrating sound level meters have the same centre values and differ only in the tolerances allowed. Tolerances broaden as the type number increases.This standard specifies electrical and acoustical tests to verify compliance with the characteristics specified (see Sub-clause 1.3).