dBA, NR, NC & PNC#
The single figure index for rain noise calculations can be changed from the Settings window. Select Settings > Calculation > Roof > Assessment Criteria:

dBA#
A-weighted Decibel. The A-weighting approximates the response of the human ear.
NR#
Noise Rating. A single number rating which is based on the sound level in the octave bands 31.5Hz - 8kHz inclusive, generally used to assess noise from mechanical services in buildings.
NC#
Noise Criteria. A single number rating which is based on the sound level in the octave bands 31.5Hz - 8kHz inclusive, generally used to assess noise from mechanical services.
PNC#
Preferred Noise Criteira. A single number rating which is based on the sound level in the octave bands 31.5Hz - 8kHz inclusive, generally used to assess noise from mechanical services.