Caverion equips numerous Austrian tunnel installations with a technically sophisticated system comprising power distribution, safety technology, ventilation, lighting, traffic technology and process control engineering, thereby contributing significantly to road user safety.
The daily volume of traffic places great demands on technical planning in the area of road construction and on tunnel installations in particular. For the operator ASFINAG, the safety aspect is paramount in the construction of new roads and their ongoing modernisation. In an emergency, tunnel safety is determined by a synergy of the road user's attentiveness and a rapid response time achieved by means of optimal technical safety solutions.
Safety through competence
Karl Ledermüller, Head of the Competence Centre, briefly outlines the task at hand: “The tunnel technology is a complex system which has to meet the most stringent safety requirements. It's not just about power distribution, ventilation, and a few lights for emergency call points. Behind the scenes, the data that is continuously collected in the active tunnel installations with regard to the volume of traffic, fire detectors, motion sensors, etc., must be recorded via a process control system as well as being managed and visualised through a process control centre such as the one in Ardning. We use our in-house software development for this purpose.”
Ensuring the shortest possible response times
If – taking Ardning as an example – an alarm is triggered in one of the 25 monitored tunnel installations because a car is driving too slowly, smoke has formed or someone has opened the doors to the emergency call bay, explains Project Manager Helmut Wallner , “A signal is sent to the control centre and the relevant video camera image is displayed on the large video wall. This makes it possible to view the incident immediately to ensure a rapid response time.”
Fire safety test: Nothing is left to chance
One of the highlights during completion and acceptance by the customer is without doubt the performance of the fire safety test, which is required by law. “In simulated fires with a fire load of approx. two megawatts, which is roughly equivalent to the collision of two HGVs,” explains Karl Ledermüller, “we check whether people located in the tunnel are able to rescue themselves.”
In this case, the system comprising automatic fire location detection and correct fan operation must function to perfection. As Karl Ledermüller emphasises, self-rescue is only possible if the fans keep the smoke on the tunnel ceiling at the flow velocity appropriate to the prevailing situation for a specific period and divert it to the outside in an orderly manner.
The test is considered to have been passed successfully if the fire has been detected within 90 seconds of its ignition and all the subsequent fire safety measures have been initiated by the automation programs.
“The entire team is really tense before the fire safety test,” says Karl Ledermüller “People run through the processes in their minds again to make sure everything is in place, right up until the last second
Recent projects: the modernisation of the tunnel installations in Bruck an der Mur on the S6, construction of the new Zederhaus enclosure on the A10, construction of the new Lambach tunnel on the B1, and connection of a new tunnel to the central control system in Ardning.
Austria a typical transit country and mountains account for up to 65% of its entire surface area. Austria is traversed by a 125,000 km road network; some 140 tunnels with a total length of around 345 km have been built on its motorways.