Developing definitions for maximum noise level in environmental noise evaluation

Requirements for exterior noise are commonly based on average or equivalent noise levels, such as Ldn. Modern standards and design requirements increasingly include maximum hourly level criteria, such as certain ANSI and ASHRAE standards, and CHPS and LEED design guidelines. Some cities have code requirements for maximum noise level from short events, such as trains. However, there is no definition of the maximum noise level in most of these cases. There is no shortage of candidate ratings, most based on statistical measures of the noise distribution, and the choice of rating will greatly affect the evaluation. The authors have analyzed a long-running dataset of traffic noise and additional long-term monitoring of sites exposed to railroads to evaluate candidate maximum noise level ratings. Definitions for maximum noise level are suggested for several conditions.