Abstract This paper presents a method for constructing a critical iso-dbA contour map on a plant layout at both maximum and minimum sound levels. The resultant map identifies areas in the plant that are within noise level standards, those that are in excess of noise level standards, and those which fluctuate above and below the critical noise level. A method is then presented for determining the “noise exposure factor” for those areas that fluctuate above and below the critical noise level. This factor, when combined with the critical iso-dbA map, results in a compliance map. The final compliance map defines areas in the plant that are within noise level standards and those areas which exceed noise level standards.