DIN 45657:2013-04

The document applies to sound level meters for special measurement tasks, particularly for - measuring the maximum level in consecutive time intervals, - measuring the statistical level distribution or exceedance levels, - measuring impulsive noise with time weighting I, - measuring ultrasound in the presence of audible noise with frequency weighting AU. The application of these additional requirements has to be agreed upon separately. Maximum permitted values of the expanded measurement uncertainty of the testing laboratory are specified for each of these measurement quantities. The tests and acceptance limits are inline with the specifications of DIN EN 61672-1 and DIN EN 61672-2.