BS 4142:1997 | BS 4142:2014 |
Mixed industrial and residential areas where the source only is considered | Significant widening in the scope to include industrial and commercial sources, all situations and noise sensitive dwellings |
Assessment reference period was 5 minutes during the night | New assessment reference period of 15 minutes at night |
Single correction of 5 dB for one or several acoustic features | Graduated corrections for tonal and impulsive character plus corrections for other features. Penalties are additive. |
Subjective | Subjective or objective |
Likelihood of complaints | Likelihood of adverse impacts |
Rating level minus background L A90 | Rating level minus background L plus A90 context |
20 dB range (-10 to +10dB) | 10 dB range (0 to +10dB) |
Uncertainty not mentioned in standard | Report to include a consideration of uncertainty |