Automatic fire detection in road traffic tunnels

Fire detection experiments in a road traffic tunnel were performed in the Runehamar test tunnel 5th–8th March 2007. The Runehamar test tunnel is a full profile road traffic tunnel, 1.65 km long, located outside Åndalsnes, Norway. The goal was to examinate smoke and heat detection systems to determinate what kind of principle best suited for detecting a fire in an early stage. The systems were tested during small Heptane pool fires, varying between 0.16 m2 and 1 m2, giving heat release rates from 0.2 MW to 2.4 MW accordingly, and one car fire of about 3–5 MW, and with wind conditions varying from 1.1 m s−1 to 1.6 m s−1. The size of the fires, were designed to be in the range from impossible to difficult to detect. The results were conclusive. Earliest detection of a car fire, fire starts inside, was by smoke detection given fixed limits (3000 μg m−3). With open pool fires, or immediate flames, continues fibre optical heat detection systems was faster given the limits 3 °C/4 min.