Are there any limits to Air Horns?
Are there any limits to Air Horns?
"For some months now, in addition to their usual sirens, some fire engines have been using powerful horns originally made for river navigation. As this practice is fairly recent and their sounds are really very powerful and aggressive, I would like to know if they have been included in a new federal or cantonal law? Aren't there any noise standards to protect the public?
V. Geneva
Air horns are compressed air-operated horns that produce a sound of up to 150 decibels (dB) or more. This level of power is more or less equivalent to the noise produced by a plane taking off! It is estimated that at 85 dB and above, prolonged listening can damage the inner ear...
In Switzerland, the sound of horns and alternating-tone horns fitted to priority vehicles is governed by Appendix 11 of the Ordinance on Technical Requirements for Road Vehicles (OETV). This stipulates that mandatory horns, i.e. the ordinary horns found on cars, must have a sound intensity of at least 87 dB and no more than 112 dB. Emergency vehicle horns must be at least 100 dB and no more than 115 dB loud.
It's true that in Geneva, some fire trucks have been equipped with "Air Horns" for some twenty years now. These are the large vehicles that contain the products needed for the first few minutes of fire-fighting and that open the fire service convoy. It goes without saying that the sound power emitted by their sirens and horns is strictly controlled and does not exceed legal limits.
The fact that the sound produced by these specific horns seems much more powerful than that of conventional sirens can be explained in several ways. Firstly, their sound is much deeper than that of sirens, which gives an impression of power. Secondly, they are often used at crossroads, i.e. in places that resonate. Finally, it's important to remember that every 3 dB increase is equivalent to a doubling of the sound intensity! It's worth pointing out that drivers of these big pumpers are advised to use these horns with a degree of moderation, especially if children are in the vicinity.
