1.1 This Standard provides a procedure to predict the sound level received at a distance from an industrial plant that is due to sound from the plant.
(1) It is envisaged that this method will be used to predict sound levels (Leq, Lmax, etc) from the industrial plant being considered at the property line or at nearby residences.
(2) This procedure only predicts sound levels produced by the sources being considered. Background sound levels due to traffic, other plants, etc, not taken into account by the prediction may already exist at particular receivers.
1.2 To use this Standard, noise source information shall be available as sound power or sound pressure levels in octave or one-third octave bands.
Note: This prediction may be taken as representative of the upper limit of sound levels. Ground effect, which can reduce sound levels by up to 20 dB, is not part of the prediction. Weather conditions (principally temperature inversions and following winds) that considerably reduce ground effect are common in temperate climates. If measurements are made to confirm these upper-limit predicted values, they should be taken downwind from the source or during a temperature inversion. If ground effect is to be considered, a simple approach is to use the difference in propagation between hard and soft ground given in Table 3.5 of the CMHC Publication Road and Rail Noise: Effects on Housing.