Basics: office acoustics
The notion that noise can affect health and working capacity has today virtually become a truism. But the notion that noise at the volume of normal conversation can lead to mental strain and be felt as stress does not yet appear to be sufficiently known. The acoustic quality of a workspace is hugely important, especially in an office, where concentration and communication are required. Because permanent noise emissions and the so-called informative noise, which forces people to constantly “close their ears”, trigger significant stress responses, resulting in slower thinking processes, reduced attentiveness, and longer reaction times.
The modern-day trend of open-plan offices, where various work areas are integrated into one room in order to promote communication, sets the highest standards in acoustic conditions. Room acoustics are primarily influenced by building structure and the materials used in it. Sound-proofing fittings, quiet equipment (Blue Angel seal) and functional design (space between work stations)/spatial structuring with sound-absorbing partitions are other key aspects.
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Sound pressure level
The sound pressure level in dB (A) indicates how loud the noise is perceived by the human ear. It depends heavily on how far away the sound source is. The auditory threshold is zero, defined as 0 dB.
Sound power level
Indicates the strength of the sound source (sound emission), and is definitive when comparing equipment and machinery noise.
dB and dB (A) decibels
dB is the logarithmic measuring unit for the sound pressure level. The SPL’s A-rating takes into account the audiogram for the human ear. People hear based on frequency; deep tones register more loudly than high ones.
Rating level or daily exposure level
This is the average noise exposure during the working day, and takes into account all noises occurring at the workplace. It does not include the noise level caused by the affected person themselves.
Reverberation time
The reverberation time is the amount of time a sound lingers in a room until it is no longer audible. It is the most important parameter for acoustic quality in rooms. The lower it is, the better the intelligibility. Reverberation time is impacted by the proportion of sound-absorbing surfaces in the room.
Sound propagation
Sound propagation also says something about a room’s reflective and absorption properties. It indicates the average drop in sound pressure level in the room from the sound source to the work station. The decrease in sound pressure level is stated per doubling in distance. Out in the open, this is 6 dB.
A low reverberation time and intense decrease in sound propagation indicate good room acoustics. Today, however, office acoustic quality is assessed in much greater detail. Parameters such as “deflection distance” (the distance at which another person’s speech is no longer intelligible and no longer deflects), “confidentiality distance” or “A-rated sound pressure level at a distance of 4 m” are all included in the assessment. Proper sound barriers between work stations, sufficient sound-absorbing surfaces, and zoned work areas based on communication-intensive/concentration-based tasks also ensure good readings here.
35 to 40 dB (A)
A very high need for concentration, e.g. in tasks such as sophisticated processing, programming or scientific work (cf. German Federal Institute of Occupational Safety and Health “Ergonomic findings” AWE 124)
35 to 45 dB (A)
For concentrated, predominantly intellectual work (cf. DIN EN ISO 11690, AWE 124)
40 to 45 dB (A)
For necessary communications with customers, and other situations requiring excellent intelligibility (cf. DIN EN ISO 9241 Part 6)
40 – 50 dB (A)
At call centres and screen work in a commercial environment (cf. AWE 124, Call Centre Knowledge Store, German Federal Institute of Occupational Safety and Health)
45 to 55 dB (A)
For routine office work (cf. DIN EN ISO 11690)
| dB (A) | Subjective perception | Type of noise | Health impact |
|---|---|---|---|
| 10 | Inaudible | Breathing sounds 30 cm away | Safe range |
| 30 | Very quiet | Whispering or clock ticking | Safe range |
| 40 | Quiet | Quiet radio music | Possible mental and autonomic reactions |
| 50 | Quiet | Laser printer | Possible mental and autonomic reactions |
| 60 | Loud | Normal conversation (2 m) | Start of autonomic damage |
| 70 | Very loud | Matrix or daisy wheel printer, loud voices | Nervous dysfunction |
| 80 (noise) | Very loud | Car 7 m away, heavy street traffic | Clear autonomic damage |
| 90 | Very loud | Truck 5 m away | Hazardous range, start of hearing damage |
| 100 | Very loud | Nightclub | Hazardous range, start of hearing damage |
| 110 | Unbearable | Aircraft engine 240 m away | Hazardous range |
| 120 | Unbearable | Aircraft engine 30 m away | Damage to the central nervous system |
| 150-180 | Unbearable | Rocket engine | Paralysis and death of organisms |
With REISS’ modular, highly effective sound-proofing and screening systems, you can tailor your office acoustics to your requirements in terms of space and task areas – from acoustic zoning in open-plan offices, to sound-proofing at work stations, to acoustic separation of meeting areas. REISS offers comprehensive consultancy on the office acoustic factors relevant to you, and how to best implement the 23/24 and 41/42 systems, as well as the REISS UNI panel system.
