MT 4 Sound level meters

Sound level meters are instruments intended to measure sound levels generally in the range of human hearing, either with an operator present or for automatic and continuous measurements of sound level without an operator present. A sound level meter may be a self-contained instrument including a microphone and a display, or comprised of separate components in one or more enclosures including general-purpose computers, printers, and other devices.

Personal sound exposure meters are intended for measurement of sound exposure in the vicinity of a person’s head. The microphone of a personal sound exposure meter is intended to be worn on a person. A typical application is to determine occupational noise exposure.

IEC 61672 provides electroacoustical performance specifications and corresponding test methods for time-weighting sound level meters, integrating-averaging sound level meters, and integrating sound level meters for measurement of sound levels and sound exposure levels. Sound level meters have a specified frequency response for soud incident on the microphone from one principal direction in an acoustic free field or successively from random directions.

According to IEC 61252, a personal sound exposure meter is intended to measure sound exposure as the time integral of the square of the instantaneous A-frequency-weighted sound pressure resulting from steady, intermittent, fluctuating, irregular, or impulsive sounds. The document specifies acoustical and electrical performance requirements for personal sound exposure meters and specified ranges of environmental conditions for operation.

Standardisation is necessary for a range of reasons, including:

-Enabling instruments of suitable quality to be produced and marketed

-Practicability and consistency of testing of instruments

-Assurance of accuracy of measured sound levels

-Consistency of measured sound levels to enable comparison of results between users

Convenor

Peter Hanes

Peter.Hanes@nrc-cnrc.gc.ca