Is issuing a calibration certificate from a sound level meter sufficient?
It is generally invalid to issue only a calibration certificate for a sound level meter, because the calibration certificate only issues a basic data report, and the issued report cannot cover all required inspection items, so it is impossible to judge the accuracy level of the instrument or even judge whether the sound level meter is qualified based on the data in the calibration report. The risk of random use of a sound level meter is high when it is not clear whether the accuracy level of the sound level meter is qualified. Only a sound level meter that has issued a verification certificate and drawn a qualified conclusion and accuracy level can be used normally.
The sound level meter is a measuring instrument for mandatory verification. If the verification agency only issues a calibration certificate or a test report, it means that the performance index of the sound level meter cannot meet the requirements of GB/T 3785.1-2010 (IEC 61672-1:2013), and the verification is unqualified according to the verification regulation JJG 188-2017.
Another situation is that the sound level meter itself is qualified, but if the measurement unit has no verification qualification or the testing equipment is incomplete, it can only issue a calibration certificate. This type of sound level meter cannot be used in places such as environmental monitoring, so the sound level meter must be sent to a measurement unit with verification qualification for verification.
Measuring range of sound level meter
The measurement range of the sound level meter is the main technical index of the sound level meter. This technical index represents the technical advancement of the product to some extent. Generally, the wider the measurement range, the better. The measurement upper limit of the sound level meter is determined by the maximum undistorted sound level of the sound level meter, which can generally reach 130 dB; if a high sound pressure level (for example, 172 dB) needs to be measured, a high sound pressure microphone must be selected. The measurement lower limit of the sound level meter has a lot to do with the self-generated noise of the sound level meter itself. If you want to measure low sound level noise, you should choose a sound level meter equipped with a high-sensitivity microphone.
