Strutt|Criteria|Curves|Sound Levels|PNC inserts the Preferred Noise Criterion (PNC) curve into the active row of the worksheet. The user may select which PNC curve to display by entering the curve number in Column D of the active row.
Please note that the PNC curve is only from PNC15 in 5 unit intervals to PNC65. If an intermediate value is entered, Strutt returns the nearest PNC curve - thus entering PNC26 will return the PNC25 curve, for example.
Reference: Table 18.3, Noise and Vibration Control (Beranek)