Noise in the workplace? Why quiet acoustics are so important
When we think of health-relevant environmental factors in the workplace, we think of room temperature, lighting or pollutant-free breathing air. Acoustic aspects of a workspace are often only taken seriously when high sound levels make it necessary to wear hearing protection.
We can close our eyes, but our ears are constantly receptive. Whether traffic or machine noise, music or chatter, church bells or cowbells, we are also exposed to a variety of sounds at work. This can be pleasant and is often necessary or helpful for working. However, noises and sounds become a nuisance and a burden when they are perceived as disturbing.
Sound acts in two ways
- In order to understand why sound levels far below noise limits are also an issue for occupational health and safety, it is necessary to distinguish between two aspects of the effect of acoustic perceptions on humans:Aural effects directly affect the sense of hearing (aural = affecting the ear). Above a sound pressure level of about 80 dB(A), they damage the sensory cells of the inner ear and lead to noise-induced hearing loss in the long term. Hearing protection PPE and noise protection measures are designed to protect against the aural effects of sound.
- Extraaural sound effects are called all effects that are not perceived with the ears and are therefore not related to hearing. They act in other regions of the body and trigger physical and psychological reactions.
High sound intensities always have both aural and extraaural effects. Noise not only damages hearing, but also produces physiological stress responses. These relationships of high noise levels and their consequences for health are quite well researched. However, it is less well known that even low-intensity acoustic sensations, which would hardly be called noise, can have a significant impact on our health. For a long time, this was also given little attention in occupational health and safety, since - for good reasons - the focus was on protection against noise.
Noise level at the expense of health
Everyone knows the situation often depicted in movies and comics, where the buzzing of a single fly steals the protagonist's last nerve. This is an extreme example, and in many workplaces one would be glad for a noise level at which an insect buzz would be audible. But the hum of an air conditioner, the rattle of a copier or a colleague's blaring radio can also become disruptive factors at work. How much and how quickly unwanted disturbing noises affect us is perceived subjectively and is influenced by the context. Noises emitted by a valued colleague will bother us less than the sounds of someone we are critical of or like less. However, regardless of personal and situational variations, acoustic annoyances can be detrimental to health by
- Disturb our attention and lead to an error rate
- trigger the release of stress hormones and increase blood pressure and pulse rate
- promote our nervousness and irritability.
If you feel constantly disturbed by the acoustic background of your workplace, your cognitive performance will decline and your well-being will suffer. In the long run, this is anything but conducive to good health, and even comparatively quiet sound can become a stress factor.
Identify and eliminate sources of interference
Where employees complain of acoustic annoyance below noise thresholds or where the ambient noise at a workplace is perceived as disturbing, it must be examined to what extent the source of the noise can be turned off. There are no regulations or patent solutions here, as disturbing noises can have very different causes, e.g.:
- Work equipment: whirring or humming noises from drives and machines, clattering keyboards, loud PC fans or squeaky office chairs
- Building services: whirring fans and air conditioners, hissing in pipes, gurgling in heating system
- People: talking loudly on the phone, listening to the radio, chattering
In the case of technically related noise sources, cleaning and maintenance sometimes helps, and the noisy copier would be better in an adjoining room anyway. For new acquisitions, attention should be paid to the criterion "low noise", whether keyboard or machine. For furnishings, the use of silicone spray or penetrating oil - better known as Caramba or WD-40 - can work wonders and eliminate creaking or squeaking noises. Radiators can be vented and the pressure of the heating system regulated.
Preventing conflicts with consideration and a sense of proportion
If it is the dear colleagues who cause "acoustic nuisance", a sense of proportion and tact is required. Listening to the radio at work is not an uncommon conflict that requires consideration from both sides. It is not necessary - regardless of station or musical taste - to put up with a constant stream of music, nor should, for example, an entire construction crew have to do without any musical entertainment just because one individual feels disturbed.
In addition, an annoyance about noise from colleagues may have deeper reasons that have to do with the working atmosphere or psychological stress. Constant chatter can undoubtedly be disturbing, but we humans are basically social creatures; an imposed silence at the workplace cannot be the solution. Often, conversations with colleagues or customers, telephone ringing or other signals are a necessary part of everyday work. With a little consideration from all parties involved, compromises should be able to be found. Typical solutions are:
- Arrange rest periods for tasks that require concentration
- Mute smartphones consistently in multi-person offices
- Provide hearing protection or headphones
Conflicts can often be prevented by everyone thinking a little ahead. For example, if you know in advance that a phone call with a difficult customer could take longer or that you tend to speak too loudly on the phone, you can move to an unused room to make the call.
Making targeted use of acoustic design options
Apart from the directly recognizable and possibly disturbing noise sources, the acoustic perception of a room is determined by many factors. The materials of the ceiling, walls and floor have a major influence, as do the furniture, furnishings and indoor plants. A surface can reflect sound strongly and is then called sound-reflecting. Many floor coverings, on the other hand, are capable of absorbing sound.
For new installations, conversions or renovations, the building and room acoustics should be matched to the subsequent use of the room. A clever interior designer can use various criteria such as sound pressure, rating level, sound absorption coefficient or reverberation time to determine in advance, for example, whether a spoken voice will sound muffled or clear. Room acoustics also play a role in determining whether we perceive a conversation or training session as stressful or as pleasant. There is no ranking list of acoustic optimization, but individual solutions are required. This is because the structural conditions on site, the materials used, the position of windows, the position of furniture, etc. can be very different.
In addition, the requirements for optimal acoustics are by no means the same everywhere, but vary depending on the workplace and task. For example, at the workplace in a call center, voices from the surroundings should be muffled as well as possible. In a seminar room or meeting room, on the other hand, the opposite is desired and speech intelligibility should be ensured right to the farthest corner of the room. The specific acoustic suitability of a room for certain types of use, referred to by experts as audibility, can prevent later conflicts and stress. The options for targeted acoustic room design are vast and range from sound-absorbing wall coverings and acoustic panels to ceiling canopies, lamella curtains and other acoustic elements - some of which are quite decorative - and floor coverings. Even furniture, lamps and indoor plants can have a lasting effect on room acoustics.
Last but not least, when talking about acoustics at the workplace, it is important to remember that sound also serves to transmit information. It is not unusual for acoustic messages to be relevant to safety and to indicate errors. Or they facilitate operability, such as the keyboard signal when the shift key is pressed. Under no circumstances should an acoustic warning signal be turned off simply because someone feels inconvenienced by it. Nor should warning messages be drowned out by the ringing, beeping and droning of cell phones and the like. Clear regulations and, if necessary, prohibitions must be provided to prevent a warning signal from losing its effectiveness due to acoustic overstimulation.
This technical article appeared in the printed edition SAFETY-PLUS 1-2022.
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