Seminar by Lucas Lenne

Influence of the type of discussion on the deleterious effects of noise in open-plan offices : a laboratory experiment.

A critical analysis of the indicators used for the evaluation of the acoustic quality of open-plan offices was conducted based on their ability to differentiate offices with various acoustic treatments (comparison of the measurement uncertainties and their variation range), and their relation with the deleterious effects of conversational noise (annoyance, fatigue, etc.). It appears that the indicators are not suited to evaluate the acoustic quality of activity-based offices (offices accommodating several activities). Indeed, the deleterious effects of noise are greatly dependant of the task carried out by employees. The ISO 22955 (2021) standard introduces an indicator evaluating, specifically, the acoustic quality of activity-based offices. This indicatoris the attenuation of a speech signal between two areas of the office hosting different activities. The standard defines target values for each combination of activity, which aim to implement differentiated acoustic treatments according to the two activities considered. For example, a breakout area must be more insulated from the rest of the office than an areas used as a call centre. This is not really in line with the commonly made assumption that links the deleterious effects of speech noise to its intelligibility.
In this context, a laboratory experiment to evaluate the influence of the type of discussion on the adverse effects of noise was conducted. 8 acoustic conditions were considered. They consisted of a speech noise and a ventilation noise. They were defined by the type of discussion (from a breakout area or a call centre) and the SNR. 32 subjects participated in the experiment. In each acoustic conditions, they had to take notes on a corpus of press articles during 35 min. Following this press review, their perception of the acoustic environment, their perceived fatigue and the mental workload were evaluated using questionnaires. This experiment is the subject of the presentation.