Acoustical annoyance of workers in tertiary sector: risk assessment and solutions of prevention.

The numerous employees working in open-space are very rarely exposed to noise hazards. They are in contrast exposed to noise coming from equipment or conversations which cause discomfort and fatigue and divert their attention. This type of noise is then a nuisance which has to be assessed then reduced. To achieve this goal, several actions have been started in the last years. Because these are not legal requirements, international standards as well as national standards aim to publish guidance values for the company hygienist or to the open-space designer in order to obtain acoustical properties (ambient noise, intelligibility, discretion) matched to the required work. Models developed for processing the sound ambiance are still in progress in order to evaluate some solutions before design or for correction of existing situations. Ground evaluations have to include measurements for assessing classical parameters (ambient noise, spatial decay as well as time decay) or less classical parameters (intelligibility, modulation rate) and for cross-checking these data with surveys of the employees’ feelings. Latest studies show that the discomfort is of course strongly linked to the noise intelligibility but that, on the one hand, classical intelligibility indexes fail to measure the employees’ performance decrease, and that, on the other hand, workers are able to increase the work load or effort to compensate the discomfort, aiming to reach the same work results. To go further, future studies should show how the full-day fatigue is linked to the noise sources or if the spatial repartition of sources is of prime importance for the discomfort feeling.