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ISO 16283 for measuring sound insulation in buildings supersedes ISO 140 but is particularly lacking for measurements in large, open rooms of the type considered here (floor volume: ~4000 m3). Following ISO 16283-1, the room volume is theoretically divided into smaller volumes through an analysis of sound level distribution. Large absorbing panels in the ceiling prevent the growth of diffuse sound fields, and thus, the analysis makes critical use of normalization factors used in the airborne sound insulation and impact noise levels based on the Sabine equation. Given the likely division of finished floors into rooms, mobile separation walls are used here to investigate the influence of partitions on sound insulation. The results seem to show that they reduce sound insulation and increase impact noise level in each considered enclosed volume. These variations were investigated further through measurements taken in two volumes of different dimensions and at positions near to and far away from the separation walls.

The international standards governing the measurement of sound insulation in buildings (ISO 140) do not explicitly cover the methodology of taking measurements in large open rooms. A building with open plan floors, each of about 1300 m2, is considered here. The ISO 140-14 standard, through an analysis of sound level distribution, allowed smaller partitions to be identified and used as reference volumes. Different index calculation methods allowed critical issues to be highlighted. The impact sound index was strongly affected by geometry (i.e., volume); therefore, its calculation using different virtual volumes gave differing results. Furthermore, the index calculated using the logarithmic average of the indices for each virtual volume and an extended analysis of measurements over the entire floor provided different results. The airborne sound insulation index was demonstrated to be independent of the choice of virtual volumes; it could be consistently calculated using either the logarithmic average or the extended analysis.