Noise In Open-plan Offices Research Articles

Relation between occupation density and ambient noise in open plan offices: a study based on field measurements

Although progress has been made over the last decade on the issue of well-being in open-plan offices, recent surveys show that employees are still dissatisfied with their working environment, particularly the noise environment, remains. However, standards exist to help ensure that open-plan offices are designed to provide the best possible working environment. But, because of the scope of these standards, their recommendations can be contradictory. For example, the French ergonomics standard NF X35-102 makes recommendations on the sizing of workstations, likely to lead to office occupancy densities that are incompatible with the ambient noise level objectives defined in the ISO 22955 standard. To resolve these contradictions, a field measurement protocol was implemented. It consists in (1) a real-time count of the number of people in the office, (2) a measurement of ambient noise, (3) a questionnaire assessing employees' perception of their physical working environment. The data collected in several French companies will make it possible to establish relationships between the ambient noise level, the occupancy density and the perception of noise levels. This paper presents an occupancy sensor developed for this study and measurements of ambient noise level and occupancy ratio during a working day in an open-plan office.

Field study for the evaluation of the acoustic quality of open-plan offices

Even if the global health crisis is currently changing the work organisation in offices in the service industry, the problem of noise in open plan offices remains a major challenge with regard to occupational health and well-being. Since 2012, the French National Research and Safety Institute for the Prevention of Occupational Accidents and Diseases (INRS) has been carrying out acoustic surveys in French open-plan offices by measuring both some usual indicators of empty offices (Tr, D2S, Lp4m, rc, Lp) and also the ambient noise levels in activity. In addition, GABO questionnaires have been proposed to employees to assess their perception of the noise environment. So far, 50 open spaces were evaluated, with more or less data collected depending on the situation encountered. Approximately 1,400 employees have already answered the questionnaire. All of the sites visited cover the entire set of activities described by the ISO 22955 standard. An analysis of the links between the acoustic parameters and the perception of employees was carried out. This analysis provides additional information to the studies on the choice of acoustic descriptors and on the use of sound masking systems that aim to control background noise to reduce noise disturbance due to intelligible conversations.

Effect of visual elements on Indoor soundscape perception in open-plan office

This study examined the effect of changes in visual elements on spatial comfort and work productivity in the aspect of indoor soundscape perception in the open-plan office (OPO) sound environment. Various OPO visual stimuli were simulated using computer software (Unity 3D engine) to change the visual environment by varying variables such as worker density, window ratio, green ratio, and ceiling height. An interactive virtual reality environment was implemented to perform a specific task while experiencing the audio-visual stimuli combining the general OPO noise stimulus and the simulated OPO visual stimulus. Subjective evaluation was performed on a total of 30 subjects to evaluate indoor soundscape quality and work performance for each stimulus. Based on the results of this study, a pleasant OPO design guideline was proposed. Keywords: Open-plan office, indoor soundscape, interactive VR test, spatial comfort

Open-plan office noise is stressful: multimodal stress detection in a simulated work environment

AbstractThe coronavirus disease 2019 (COVID-2019)-induced changes in the workplace present a timely opportunity for human resource management practitioners to consider and remediate the deleterious effects of noise, a commonly cited complaint of employees working in open-plan office (OPO) environments. While self-reports suggest that OPO noise is perceived as a stressor, there is little experimental research comprehensively investigating the effects of noise on employees in terms of their cognitive performance, physiological indicators of stress, and affect. Employing a simulated office setting, we compared the effects of a typical OPO auditory environment to a quieter private office auditory environment on a range of objective and subjective measures of well-being and performance. While OPO noise did not reduce immediate cognitive task performance compared to the quieter environment, it did reduce psychological well-being as evidenced by self-reports of mood, facial expressions of emotion, and physiological indicators of stress in the form of heartrate and skin conductivity. Our research highlights the importance of using a multimodal approach to assess the impact of workplace stressors such as noise. Such an approach will allow HR practitioners to make data-driven recommendations about the design and modification of workspaces to minimize negative effects and support employee well-being.

Investigation of the Barrier Effectiveness in Open-Planned Offices: A Sample Analysis

It is possible to give speech sound as the primary source of noise in open plan offices. The noise caused by the speech voice has an impact on both the intelligibility of speech and the confidentiality of speech. For jobs and areas that require a high level of perception, the acoustically unsuitable work environment often causes distraction, resulting in a reduction in labor productivity. Therefore, in the study: it is aimed to present concrete precautions to be taken in order to provide auditory comfort for open plan offices at the design stage. According to TS EN ISO 3382-3 standard, STI value in the nearest working unit, Aweighted sound pressure level of the speech unit, as well as distance (rD) and distance (rP) where privacy begins to decrease over two open-plan office projects. The relationship between the rate of reduction (D2, S), the A-weighted sound pressure level (Lp, A, S, 4 m) of the speech sound at a distance of 4m, the background noise level (Lp, A, B) with the variability of the obstacle design used between ODEON 15.14 volume acoustics were analyzed and analyzed by simulation program. Keywords: Open-planned office, barrier design, architectural acoustics, noise control. DOI: 10.7176/JSTR/6-04-10

Long-term effects of the use of a sound masking system in open-plan offices: A field study

Noise in open-plan offices, and more specifically conversational noise, is a major source of annoyance for employees. The principle of sound masking consists in artificially increasing the background noise in the office, which leads to a decrease in speech intelligibility and therefore a reduction in acoustic annoyance. Nevertheless, the arguments in favour of this technology are based on short-term laboratory studies, whose lack of representativeness limits the application of their conclusions in real open-plan offices. This justifies the present study, which aims to evaluate, in situ and over the long term, the effectiveness of a sound masking system that meets the main scientific and normative recommendations (for example, a masking level below 45 dB(A) and a spectrum with a slope of approximately − 5 dB per octave). Such a sound masking system was installed for several months in an office of a major French banking company. The experiment spanned 26 weeks, 14 of which corresponded to nominal operation of the masking system. The protocol was based on subjective measurements using questionnaires on perceived fatigue, mental workload and perception of the soundscape. The study did not reveal any significant improvement in the assessed psychological factors nor in annoyance caused by office noise. On the contrary, it showed an increase in annoyance caused by noise from office equipment. This highlights the fact that a masking level of 45 dB(A) might already be too high. The results therefore suggest that, in real conditions, a masking system, even if it is used according to specifications that seem to be agreed upon, is not a turnkey solution to the problem of noise in open-plan offices. It is recommended that the installation of these systems be preceded by a holistic analysis of the office: acoustic quality of the room, layout of the workstations and the activities that take place there.

Computational studies of speech intelligibility in open-plan offices

Noise in open-plan offices, connected with an unintentional hearing of conversations and related distraction of attention, causes annoyance of employees. The article presents the calculated range of speech intelligibility in a selected open-plan office room. The speech transmission index (STI) was examined in a real room of 300 m3. The room was equipped with a sound absorbing suspended ceiling, acoustic screens and sound absorbing materials on the walls. Initial tests were conducted in order to verify the assumed computational model from ODEON software, as well as the geometrical and acoustic data describing the room. The verification process consisted of comparing the calculations and measurement results. In the main part of the study, the range of speech intelligibility was calculated for several locations of the speech source, i.e., areas in which the STI > 0.5. The results of the calculations and the results of the measurements of physical quantities, characterizing the acoustic properties of the open-plan office room (including STI), showed good agreement. For speech emission, the ranges of speech intelligibility were determined on several work stations. The use of calculation methods to simulate the sound field in open-plan office rooms is possible when the calibration of the room model is initially performed. Determination of the speech intelligibility range provides important information about the distance of negative acoustic interactions between work stations. This range can be used to determine the interaction between work stations or to assess various technical solutions to reduce the negative interaction. Med Pr. 2019;70(3):327-42.

A Cross-Sectional Survey on the Impact of Irrelevant Speech Noise on Annoyance, Mental Health and Well-being, Performance and Occupants' Behavior in Shared and Open-Plan Offices.

This cross-sectional survey has compared subjective outcomes obtained from workers in shared (2–5 occupants) and open-plan (+5 occupants) offices, related to irrelevant speech, which is the noise that is generated from conversations between colleagues, telephone calls and laughter. Answers from 1078 subjects (55% in shared offices and 45% in open-plan offices) have shown that irrelevant speech increases noise annoyance, decreases work performance, and increases symptoms related to mental health and well-being more in open-plan than in shared offices. Workers often use headphones with music to contrast irrelevant speech in open-plan offices, while they take a break, change their working space, close the door or work from home in shared offices. Being female, when there are more than 20 occupants, and working in southern cities without acoustic treatments in the office, make it more likely for the occupants to be annoyed by irrelevant speech noise in open-plan offices. While, working in southern cities and with acoustic treatments in the office makes it more likely that noise annoyance will be reported in shared offices. Finally, more than 70% of the interviewed in open-plan offices were willing to reduce their voice volumes when advised by a noise monitoring system with a lighting feedback.

Empirical Study of Room Acoustic Conditions and Neurophysiologic Strain in Staff Working in Special Open-Plan Bank Offices

Noise in open-plan offices induces psychological stress and fatigue in staff. Focusing on workstations and noise exposure, this study investigated acoustic conditions in special open-plan offices and their relationship with neurophysiologic strain. Twenty banks and 104 participants were randomly selected. Acoustic properties of banks and workstation partitions were assessed using the ISO criteria and speech transmission index (STI). Equivalent noise level (LAeq) of the staff was measured in three 30-min intervals, and skin conductance level (SCL) and respiratory rate (RR) of staff were assessed in three 5-min intervals at the beginning, in the middle, and at the end of the work hours. The intelligibility of speech between staff workstations (SW) was better than that between staff and clients (SC however, with increasing STI between SW and with decreasing STI between S&C, the staff strain increased. With increasing noise exposure, psychological stress of the staff increased too. Because of the acoustic condition and partitions used in the banks, the acoustic comfort of staff was not desirable. Since many other banks use such partitions, any improvement in partitions between workstations can enhance acoustic comfort in the banks.

Acoustic conditions in open plan office - Application of technical measures in a typical room

Noise in open plan offices should not exceed acceptable levels for the hearing protection. Its major negative effects on employees are nuisance and impediment in execution of work. Specific technical solutions should be introduced to provide proper acoustic conditions for work performance. Acoustic evaluation of a typical open plan office was presented in the article published in "Medycyna Pracy" 5/2016. None of the rooms meets all the criteria, therefore, in this article one of the rooms was chosen to apply different technical solutions to check the possibility of reaching proper acoustic conditions. Acoustic effectiveness of those solutions was verified by means of digital simulation. The model was checked by comparing the results of measurements and calculations before using simulation. The analyzis revealed that open plan offices supplemented with signals for masking speech signals can meet all the required criteria. It is relatively easy to reach proper reverberation time (i.e., sound absorption). It is more difficult to reach proper values of evaluation parameters determined from A-weighted sound pressure level (SPLA) of speech. The most difficult is to provide proper values of evaluation parameters determined from speech transmission index (STI). Finally, it is necessary (besides acoustic treatment) to use devices for speech masking. The study proved that it is technically possible to reach proper acoustic condition. Main causes of employees complaints in open plan office are inadequate acoustic work conditions. Therefore, it is necessary to apply specific technical solutions - not only sound absorbing suspended ceiling and high acoustic barriers, but also devices for speech masking. Med Pr 2018;69(2):153-165.

Balancing the detrimental effects of office noise annoyance and distraction on work performance

Broadband, steady-state background noise can improve open office conditions by facilitating speech privacy and reducing distraction caused by intermittent, occupancy-generated noise. The background noise is typically generated by HVAC systems, though can be added with loudspeakers to boost speech masking. However, too high background noise levels can cause annoyance, fatigue, and other noise-related symptoms. It is yet unclear whether noise annoyance or distraction impairs work performance more. This study investigated the trade-off between noise annoyance and distraction, as well as their effects on acoustic dissatisfaction and performance. Subjects performed cognitive tasks while exposed to simulated office acoustic environments reproduced using higher-order Ambisonics. At fixed time intervals, the subjects could change the acoustic environment by adjusting either the background or intermittent noise levels. Lowering background noise caused the intermittent noise to rise, and vice versa. By the end of testing, it was expected that each subject equalized their dissatisfactions of the two noise types. Annoyance and distraction were assessed with a survey at each time interval. Physiological measures, including heart rate variability and skin conductance, were collected to correlate arousal/stress levels with each acoustic environment. The results of the study may provide context to effectively utilize background noise in open-plan offices.

A simple sound metric for evaluating sound annoyance in open-plan offices

Noise in open-plan offices has become a major health issue. Intelligible speech is considered as the most annoying noise sources by the occupants of such offices. Speech level fluctuations prevent people from achieving some high-demanding tasks, thus inducing annoyance and tiredness. Many studies were conducted in order to identify a sound metric closely related to this Irrelevant Speech Effect. Hongisto et al. have shown that Speech Transmission Effect is appropriate for evaluating the annoyance due to a neighbor in the office. More recently, Schlittmeier et al. suggested that the Fluctuation Strength can be used to evaluate the effect of the fluctuations of the ambient noise on task performance. This paper intends to present a new metric. It is based on the measurement of short-term temporal modulation of sound level. Results indicate that it seems to be as efficient as STI or FS, while being more suitable for in-situ experiments and usable by practitioners.

Effect of self-adjustable masking noise on open-plan office worker’s concentration, task performance and attitudes

The aim of this study was to investigate the attitudes of workers in an open-plan office towards concentration, task performance and co-worker interaction when wearing earphones with masking noise and when not wearing earphones. The earphones with masking noise were evaluated over the course of a working day and the level of the office noise varied between 51 and 59dBA. The spectrum of the masking noise was brown noise modified by a PC audio controller and earphones (the spectrum of the modified brown noise was substantially different to that of brown masking noise). The participants were instructed to adjust the masking level to be loud enough to mask any offending office sound but not too loud to cause discomfort. The questionnaire based quantitative study (Study 1, n=28) indicates that disturbance to concentration and task performance is reduced by modified brown masking noise thereby confirming previous studies. However all the participants in the qualitative study, which involved both open ended questionnaire and focus group interviews, (Study 2, n=28 for open ended questionnaire and 12 for focus groups) identified that they would not use earphones with modified brown masking noise to counteract office noise. An important reason for this is that modified brown masking noise obscured nearby relevant conversations, which participants identified as being crucial to the success of their overall work task. Other participants rejected the brown masking noise delivered through earphones as it caused irritation and discomfort. It is recommended that future studies into the effectiveness of masking noise in open-plan offices should include consideration of the relevance of nearby conversations. Future studies should also consider other types of masking noise and should measure the level and duration of the masking noise.Practitioner Summary: This paper reports on a multi-methods study into the use of self-adjustable masking noise delivered through earphones to counteract the negative effects of noise on open-plan office workers. It was found that self-adjustable masking noise delivered in this way was rejected by all participants.

Release from masking of speech intelligibility due to fluctuating ambient noise in open-plan offices

The sensitivity of intelligibility to ambient noise modulation is analyzed in this paper by means of two laboratory tests. The first one consists of measuring release from masking using acoustic samples composed of speech noise synthesized in the laboratory, but also real signals measured in two open plan offices. The Speech Reception Threshold values obtained from the experiment for the synthetic signals are compared with the literature. Those obtained for the real samples show significant differences as a function of the open-plane office. Secondly, a new indicator based on the calculation of the speech transmission index (IEC 60268-16, 2011) is proposed, by taking into account the modulation of the ambient noise in the 4Hz octave band. Simultaneously, a second intelligibility experiment is performed, resulting in a very good correlation between the intelligibility scores and the new indicator. To complete the evaluation, the sound samples of the first test are reused to demonstrate that the indicator is a good descriptor of release from masking due to the modulation of ambient noise for the synthetic signals and that it is capable of classifying work spaces in terms of level of distraction.

User perspectives on outdoor noise in open-plan offices with operable windows

Recent research suggests that buildings with operable windows in general, and mixed-mode (MM) buildings in particular, can provide improved thermal comfort and control opportunities for users. However, there have been concerns about outdoor noise sources such as traffic or construction noise when windows are opened. Concerns like these may hinder the installation of operable windows in buildings. This article examines 23,000 office building occupants’ perspectives on noise from both sealed and naturally ventilated/MM buildings. The results suggest that occupants near operable windows are more satisfied than those near sealed windows or those far from either window type. Among occupants dissatisfied with noise, complaints about indoor noise sources (such as people talking to each other) are about 10 times more prevalent than outdoor noise complaints.

Implementation of diffraction in a ray-tracing model for the prediction of noise in open-plan offices

Sound prediction in open-plan offices is a real challenge because of the complexity of the layout of such offices, and therefore because of the multitude of acoustic phenomena involved. One such phenomenon, of primary importance, and not the least challenging of them, is the diffraction by screens and low dividers that usually partition the workspace. This paper describes implementing the equations of the Uniform Theory of Diffraction [McNamara et al. (1990). Introduction to the Uniform Theory of Diffraction (Artech House, Boston)] in an existing ray-tracing model initially dedicated to sound prediction in industrial premises. For the purposes of validation, a series of measurements was conducted in a semi-anechoic chamber in the same manner as Wang and Bradley [(2002). Appl. Acoust. 63, 849-866] but including real desktops instead of single screens. A first phase was dedicated to controlling the quality of the installation by making comparisons with McNamara's solution for a single screen on a rigid floor. Then, the validation itself was conducted with measurements on real desktops, first without a ceiling, and then with a rigid ceiling suspended above the double desk. The results of the comparisons between calculations and measurements in this configuration have demonstrated that the model is an effective tool for predicting sound levels in an open-plan office.

Open-plan office noise: The susceptibility and suitability of different cognitive tasks for work in the presence of irrelevant speech

The aim of the present study was to test which tasks are suitable for work in open-plan offices according to how susceptible they are to disruption produced by the mere presence of irrelevant speech. The tasks were chosen to tap fundamental capacities of office work involving: search for relevant information, remembering material, counting, and generation of words. The hypothesis was that tasks requiring semantic processing should be impaired by irrelevant speech. To determine the magnitude of performance decrease, two sound conditions (quiet, irrelevant speech) were compared. The results showed that tasks based on episodic short-term-memory and rehearsal of the presented material were more sensitive to disruption by irrelevant speech than tasks which did not require rehearsal or were based on long-term memory retrieval. The present study points to the inappropriateness of tasks, such as information search and remembering of material, for work environments within which irrelevant speech is ubiquitous.

Open-plan office noise: Cognitive performance and restoration

The aim of the present study was to investigate cognitive, emotional, and physiological effects of two open-plan office noise conditions (high noise: 51 LAeq and low noise: 39 LAeq) during work in a simulated open-plan office, followed by four restoration conditions (river movie with sound, only river sound, silence, and office noise) after the work period. Students (N = 47) went through one practice session and two experimental sessions, one each with the low and high noise conditions. In each experimental session they worked for 2 h with tasks involving basic working memory processes. We also took physiological measures of stress (cortisol and catecholamines) and self-reports of mood and fatigue. Analyses indicate that the participants remembered fewer words, rated themselves as more tired, and were less motivated with work in noise compared to low noise. In the restoration phase the participants who saw a nature movie (including river sounds) rated themselves as having more energy after the restoration period in comparison with both the participants who listened to noise and river sounds. Remaining in office noise during the restoration phase also affected motivation more negatively than listening to river sounds or watching the nature movie. The findings bear on the appropriateness of open-plan office designs and the possibilities for restoration available in office settings.

Open-plan office noise levels, annoyance and countermeasures in Egypt

Open-plan office noise levels, annoyance and countermeasures in Egypt

Stress reactions to cognitively demanding tasks and open-plan office noise

To investigate the effects of cognitively demanding work tasks and office noise on heart rate variability (HRV), cardiovascular responses and electromyography (EMG) activity in the trapezius muscles. Ten female volunteers were exposed to simulated open-plan office noise for 35 min (Leq 65 dBA), while engaged in cognitively demanding tasks. Task performance, self-rated stress and energy, affective state, perceived exertion in the shoulders and in the head, EMG in the left and right trapezius muscle, blood pressure, heart period length, HRV, and salivary cortisol were measured. Cognitively demanding work tasks were associated with changes in HRV, systolic blood pressure and EMG that reflects increased sympathetic activity in the autonomic nervous system. No effect of noise was observed, except for a higher rating of perceived exertion in the head and, contrary to expectations, a 4% lower diastolic blood pressure in the noise conditions. Psychophysiological measures reflected the mental load imposed by cognitive work tasks. Short-term exposure to office noise resulted in increased ratings of perceived exertion in the head, but not in physiological stress reactions.