SOLIT² – Fire Tests and International Workshop in Spain
Within the framework of the “Safety of Life in Tunnels 2” (SOLIT2) research project an international workshop was held in Asturia, Spain captioned “Fire Suppression Systems in Tunnels” on June 22 and 23, 2011. The workshop took place at the end of a 4-week long test phase, during which in May and June 2011 more than 30 major fire tests in a 600 m long test tunnel at San Pedro de Anes were carried out. In this connection half the tests were pool fires with loads of up to 100 MW as well as solid matter fires with complete lorry loads (fire load 100 MW, consisting of wooden pallets). The test tunnel possesses a characteristic cross-section for road tunnels and is equipped with a ventilator system for longitudinal and semi-cross ventilation.
The 2-day workshop in northern Spain provided participants with an initial insight into the preliminary results of the project and an overview of the current stage of development of automatic fire fighting systems as well as the currently valid international guidelines. Further papers examined major topics dealt with in the project such as numerical simulation, life cycle costs and compensation potential.
The highlight of the workshop for those taking part was the chance to carry out large-scale fire tests within the scope of the SOLIT2 test programme in the immediate vicinity. Thus in the presence of the participants a pool fire with 60 MW load as well as a solid matter fire with a complete lorry load of wooden pallets (fire load 100 MW) was carried out. As fire tests in this magnitude can very seldom be undertaken, even for leading experts the workshop turned out to be a rare opportunity to experience such critical fires close-up.
The effect of the water mist system was something the participants could follow for themselves. In spite of the major fire load caused by the pallets it was possible to approach as much as 2 to 3 m from the fire after activating the water mist system. The unanimous opinion was expressed especially on the part of fire service personnel that it is thanks to the water mist system that it is possible to get so close to the fire thus enabling the emergency services to tackle the conflagration effectively.
In addition to the positive subjective impressions the measured values also confirmed the good impact of the water mist system: the release of heat is reduced, the temperatures around the fire sink and visibility nonetheless remains acceptable.
The tests have shown that a fire suppression system is also capable of mastering fires, which the prevailing ventilation is unable to cope with (Fig. 4).
In the German “SOLIT2” research project in particular the interaction between water mist fire suppression systems and other safety facilities in tunnels is examined. The research project has the aim of identifying compensation potentials through the application of fire fighting systems and developing practice-oriented solutions within the framework of a holistic tunnel safety concept. Furthermore numerical computation models are being further developed to reliably predict the fire course and the extinguishing effect during the application of water mist systems by means of CFD (Computational Fluid Dynamics). The fire tests serve on the one hand to optimise the water mist system and on the other provide the measurement data needed to develop and validate the software.
Apart from STUVA the partners in the project are BUNG, Fogtec, Ruhr University Bochum and TÜV Süd. It is sponsored by the Federal Ministry for Economics and Technology (duration: 2009 till 2011). The latest details about the project are obtainable from STUVA or by accessing www.solit.info.