Strutt|Criteria|Ratings|Sound Level|PN dB calculates the perceived noisiness rating (in PN dB) of the current row of the active sheet and inserts it into Column D of the active row.
Note that PN dB does not include the correction for tonal components of the noise level. To calculate this (PNLT), use the calcsheet under Strutt|Templates|Perceived Noise Level (PNLT)
Reference: ISO 3891 (1978) Acoustics - Procedure for Describing Aircraft Noise Heard on the Ground