An investigation of acoustic environments in large and medium-sized open-plan offices in China

Few studies have investigated whether employees have different acoustic demands for various types of open-plan offices (OPOs), which can be subdivided into small, medium-sized and large OPOs depending on the number of employees sharing an office. In this study, an investigation of acoustic environment is carried out in 16 OPOs, aiming to 1) study how the design parameters of OPOs affect indoor acoustic environments, and 2) explore whether occupants’ demands of acoustic environments are different between large open-plan offices (LOPOs) and medium-sized open-plan offices (MOPOs). Both objective measurement and subjective evaluation results that relate to the key aspects of the acoustic environment (noise level and speech privacy) are collected from 7 LOPOs and 9 MOPOs in China. The analysed results found that OPOs with the lower spatial density of workstations or higher storey height have the higher spatial decay rate of speech (D_2,S), lower speech level at 4 m distance (L_p,A,S,4m) and shorter comfort distance (r_C). The perceived noise level has the greatest influence on employees' acoustic satisfaction, and speech interference on employees' re-concentration is the main acoustic reason leading to work productivity decrease. In terms of the differences in acoustic environment between LOPOs and MOPOs, MOPO employees have higher acoustic satisfaction and lower disturbance levels of speech noises. Perceived speech privacy is a significant acoustic factor affecting work productivity in LOPOs, while it is not in MOPOs.