IEC 61672-1:2002 and BS EN 61672-1:2003 (Class 1)
All Acoem noise monitoring instruments are manufactured according to IEC 61672-1:2002 and BS EN 61672-1:2003 (Class 1) requirements. These regulations provide internationally recognised electro-acoustical performance specifications for three kinds of sound measuring instruments:
- A conventional sound level meter that measures exponential time-weighted sound level
- An integrating-averaging sound level meter that measures time-average sound level
- An integrating sound level meter that measures sound exposure level.
A single instrument may make any, or all, of the three kinds of measurements. Two performance categories, Class 1 and Class 2, are specified in this standard. In general, specifications for Class 1 and Class 2 sound level meters have the same design goals and differ mainly in the tolerance limits and the range of operational temperatures.
Tolerance limits for Class 2 specifications are greater than, or equal to, those for Class 1 specifications. Acoem sound level meters (Class 1) conform to the requirements of this standard and have a specified frequency response for sound incident on the microphone from one principal direction in an acoustic free field or from random directions.