You may need this approval if you intend to operate a laboratory where sound level meters are calibrated.
A sound level measuring instrument must not be used for the purposes of measuring compliance with noise regulations unless the instrument has been calibrated in a laboratory registered by the National Association of Testing Authorities (NATA), or a laboratory approved by the agency, within the previous two years.
This also applies to sound level measuring instruments used to measure the compliance of off-road vehicles with noise requirements under current legislation.