Tunnel safety in Sins
The southwest bypass is intended to relieve the village center of Sins and the access axis from traffic. The heart of the bypass - the Letten tunnel - has been open since September 2021. A complete safety system from Siemens ensures safe travel through the 912-meter tunnel.
It was one of the largest and most complex construction projects in the canton of Aargau in recent years: the Sins southwest bypass. Three years after the official start of construction, the joy of all involved is great. The opening of the Letten tunnel is a long-awaited relief from backlogs and through traffic. Despite high demands on planning, design and construction, this project of the century was successfully realized all around. This is also the opinion of the project manager for operational safety facilities (BSA), Martina Tobler.
Highest safety in the tunnel
People traveling through the Letten tunnel in the future can feel safe - thanks to the installed and interlinked safety systems. Fire detection in the tunnel driving space is handled by two different detection systems. These differ in thermal (heat) and optical (smoke) fire detection. Thus, all possible fire scenarios are reliably detected. The Fibro Laser thermal detection system from Siemens supports smoke detectors and video cameras. Through thermal detection, the Fibro Laser shows the location, the direction of propagation and the location of the fire to the nearest meter. In addition, the newly developed smoke algorithm for the detection of moving and stationary fire sources is used for the first time in the Letten tunnel.
Should a fire occur despite all safety measures, the modern video and smoke detection system from Siemens helps to locate the fire site as quickly as possible. Not only is a fire detected by the video system, but also traffic jams, lost loads and stationary vehicles.
The safe evacuation of endangered persons in the event of an incident is also ensured by a public address system - a first in a Swiss tunnel. This system has very good speech intelligibility. In the event of an emergency, this ensures an orderly and rapid evacuation of the tunnel.
All systems are coordinated with each other and function as a unit in an emergency. The detected hazard alarms are transmitted to the operations center, which is protected by the Sinteso fire alarm system. This enables potential hazards to be detected at an early stage, consequential damage to be prevented, and safety in the tunnel to be ensured.
