ERROR AND UNCERTAINTY IN NEAR-FIELD SOUND POWER ASSESSMENTS OF INDUSTRIAL SOURCES

Near-field sound pressure measurements may be converted into sound power levels (Lw) in order to populate propagation models. Although standards exist such as ISO 3740:2019 which present rigorous methods for the accurate determination of sound power levels, complying with such standards is not always feasible once an industry is operational. In such cases, it is common to see propagation models populated using a sound power estimate from a single field-based measurement. Alternatively, propagation models can be populated using sound power data that have been provided by equipment manufacturers or that have been presented in other standards such as BS 5228-1:2009+A1:2014. Previous papers commonly consider the isolated uncertainties associated with laboratory-based sound power assessments. This paper will explore multiple sources of error and uncertainty within near-field sound power estimates from field-based sound pressure levels and will suggest ways to minimise them.