In 2003, a working group of the German Federal Institute for Occupational Safety and Health (BAuA) compiled a list of three indicators for assessing the acoustic quality of office workplaces. These criteria remain valid today.
1. INDICATOR
The partial sound level caused by a single identifiable sound source should not exceed the combined sound level of all other sources by more than 4 dB(A). Otherwise, the workplace must be regarded as acoustically unfavourable.
2. INDICATOR
Conversations from other work areas and from outside should not be intelligible. This means that in small offices, the partial level of speech noise penetrating from outside should be at least 5 dB(A) below the existing background level; in open-plan offices the difference should be at least 3 dB(A). Otherwise, the workplace is to be regarded as acoustically unfavourable.
3. INDICATOR
The combined sound level from all sources should be as low as possible when the person concerned is not working. The result of this assessment can be derived from the following table:
|
Level Range (Assessment Level at Workplace) |
Acoustic Workplace Classification |
|---|---|
|
up to 30 dB(A) |
optimal |
|
> 30 dB(A) up to 40 dB(A) |
very good |
|
> 40 dB(A) up to 45 dB(A) |
good |
|
> 45 dB(A) up to 50 dB(A) |
acceptable in industrial settings |
|
> 50 dB(A) up to 55 dB(A) |
unfavourable, but still permissible |
|
> 55 dB(A) |
noise exposure too high |
The three requirements apply to all display screen workstations in offices. If the indicators lead to different evaluations, the most unfavourable result is decisive for the overall assessment of the workstation.
Source: W. Probst, Assessment and Reduction of Noise at Display Screen Workplaces in Offices and Production, Occupational Science Findings No. 124 “Display Screen Work – Noise Reduction in Open-Plan Offices”; Publisher: Federal Institute for Occupational Safety and Health, Dortmund 2003
The threshold of 55 dB(A) has since been incorporated into the Technical Rule for Workplaces ASR A3.7 Noise. This rule further states:
“For activities involving predominantly speech-dependent cognitive tasks (e.g. correction and evaluation of examination results, translations, drafting and editing of texts and documents, consulting on complex products and services in call centres or advisory offices), workplaces free from background speech must be provided. The introduction of background noise as a masker for background speech should be avoided.”
This makes it clear that in order to meet criteria 1 and 2, the sound contribution from the respective disturbing sources must be reduced. Simply increasing the general noise level in the room is permissible only in exceptional cases.
