Prognosis for the perceptibility of warning signals when hearing protectors are worn


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Web application interface
Source: IFA

The web application enables calculations to be performed of the signal audibility when hearing protectors are used for the codes W, X, S, V and Ex in the IFA list of approved products. The web application requires input of the mean values for the sound attenuation obtained in the type examination according to ISO 4869-1. This enables the five supplementary codes referred to above to be calculated.

The result of the prognosis is made available for download in the form of an MS Word file.

This prognosis is not a substitute for calculation performed officially by the IFA. The results provided here must not be used for advertising purposes or similar. Entry in the IFA list of approved products is decisive.

The web application is only available in German language. The following data and information have to be entered into the user interface:

  • Manufacturer (Hersteller)
  • Product designation (Typbezeichnung)
  • Sound attenuation values in dB (mean result of the measurements according to ISO 4869-1) (Schalldämmung in dB)
  • Choose the type of hearing protector from the drop-down list (Gehörschützerart)
  • Tick the boxes for the codes to be calculated (S, V and or Ex)
  • Start the calculation (Button "Berechnung anfordern")
  • The button “"Weitere Informationen" contains a pdf-file with background information on the origin and definition of the codes for signal audibility.


Utmost care has been taken in the development of this software in accordance with the state of the art in science and technology. It is made available to the user free of charge and is used at the user’s own risk. If at all legally permissible, liability is excluded - on whatever legal basis. Liability is excluded particularly for material defects and defects of title of the software and of the associated documentation and information - above all with respect to their correctness, accuracy, freedom from third-party properties rights and copyright, topicality, completeness and/or usability - with the exception of intention or malice.

Rights of use

The software may be freely used for non-commercial purposes. Commercial use is not permitted.

Prognosis calculator


Dr Martin Liedtke

Ergonomics, Physical environmental factors

Tel: +49 30 13001 3400
Fax: +49 30 13001 38001

Dr Sandra Dantscher

Ergonomics, Physical environmental factors

Tel: +49 30 13001 3420
Fax: +49 30 13001 38001