defr Glossar

In road and railroad tunnels, fires or dense smoke is often caused by overheated engines and turbo charges, locked brakes, defective tires, ignited cargo, etc. Fire detectors/smoke detectors installed in the tunnel serve the purpose of initiating the safety and rescuing scenario in order to allow the people to escape the area by their own devices. For this purpose, they have to detect the risk of fire as quickly as possible and to localize the event.

There are several kinds of fire detectors:

  • Linear fire alarm cables reacting to the increase in ambient temperature and allowing the localization of the fire. This method has the disadvantage that it will only detect an event when an open fire has already broken out. However, most fires in road tunnels and railroad tunnels start as smouldering fires producing life-threatening smoke fumes.

  • The video detection system of the tunnels should detect the presence of smoke as well as localize the event. Experience shows, however, that too many false alarms are triggered by extraneous light, light reflections from windscreens, change of contrast etc.

  • Scattered light measuring instruments which are based on the same photometric principle as the visibility determination. These SIGRIST instruments detect the presence of smoke very rapidly even at an early stage (cold smoke). They can also be equipped with temperature sensors and thus support localization of the event. Smoke detection

Contact distribution partner

{{selectedCountry.Name}} {{country.Name}}

Please select your businessarea


Please select


Please select your businessarea

{{selectedCountry.Name}} {{country.Name}}
{{vm.getBusinessAreaStringByVendor(vendor)}} {{area.Name}}
René Gehri
Water, Beverages & Food, Industrial Processes
Pascal Schärer
Traffic & Environment

Contact headquarters

Felix Joller
Sales Manager ScrubberGuard
Montag–Freitag 08:00–12:00 und 13:30–17:00
Feiertage & Betriebsferien:
Ostern: 15. – 18. April 2022, Auffahrt: 26. Mai 2022, Pfingstmontag: 06. Juni 2022, Fronleichnam: 16. Juni 2022, Bundesfeiertag: 01. August 2022, Maria Himmelfahrt: 15. August 2022, Allerheiligen: 01. November 2022, Maria Empfängnis: 08. Dezember 2022, Betriebsferien: 24. Dezember 2022 – 02. Januar 2023
Opening hours:
Monday–Friday 08:00am–12:00pm und 1:30pm–5:00pm
Public & company holidays:
Easter: 15. – 18. April 2022, Ascension Day: 26. May 2022, Whit Monday: 06. June 2022, Corpus Christi: 16. June 2022, Federal Holiday: 01. August 2022, Assumption Day: 15. August 2022, All Saints Day: 01. November 2022, Conception of Mary: 08. December 2022, Company holidays: 24. Decmber 2022 – 02. January 2023