The ISO (1996) noise propagation method and the simpler Swedish method (SEPA, 2012) have a similar theoretical basis, so comparison of the results was not made to validate the propagation model. Rather, comparison of the results acts primarily as a check on the consistency of the calculation procedures. Statistically there was little difference between the results obtained with either method. For A-weighted SPLs greater than 25dB, the Swedish method yielded slightly higher values, with differences ranging from 0.2 to 2.7dB, and an average difference of 1.1dB (Pearson’s linear correlation coefficient r>0.99).