There are four goals that tunnel safety has to achieve: the development of the automotive industry (hybrid and hydrogen-propelled cars) which will probably bring additional fire risks; the control of any starting fire to avoid its expansion into a largest fire with catastrophic consequences; the protection of human lives and health; and the prevention of large damages to the tunnel structure and equipment, so that traffic can resume after the damaged vehicles have been removed from the fire zone (typically 100 metres) and the area has been cleaned.
In collaboration with several other European companies, mainly from Slovenia and Croatia, Orbipark of Slovenia has created the safety concept named SafeTUNNEL that offers fire safety for tunnels and includes: SafeFOG, SafeSIGNAL, SafeVENT and SafeHYDRANT. The only possible successful disaster prevention is using a well coordinated package of integrated systems and technologies to create an efficient fire protection system like the SafeTUNNEL system. Visit www.orbipark.com
SafeFOG
In tunnel fires, most victims die due to smoke. Water mist systems cool down hot smoke and trap particles. If air velocity can be reduced under 0.5 m/s and smoke and fire zones limited to a minimum extent of 50 or 100 metres, then a robust and simple water mist system properly designed will be a huge advantage to tunnel safety.
SafeFOG is designed for 100 m-long fire and smoke zones. SafeFOG nozzles are able to produce large volumes of water mist so that a reduced number of nozzles is required in the tunnel. Standard nozzles have a capacity of 200-250 litres/minute and there is a distance of 10-20 metres between the nozzles. Only 50 or 100 nozzles per kilometre of tunnel are used, depending on the distance to the pump and tubing connection layout. A SafeFOG nozzle consists of five pieces and one of them is a screw. It is easy and cheap to open and clean or change the nozzle. The high pressure system can be controlled and opened in required sections during an emergency.
For 1,000 metres of tunnel, 2,000 or 3,000 metres of pipes are needed. All pipes within the same installation segment are of the same diameter. Diameters are 50 mm, 65 mm and 80 mm, depending on tunnel design, length, altitude difference, position of pumps in the tunnel and number of pumps.
The water tank depends on the tunnel project and has to allow minimal operation time of 30-60 minutes. A high pressure pump requires a minimum 3 bar water pressure on inlet. There are no special requirements for water quality. The pump has filters to remove particles that could obstruct the nozzles. Inspection and maintenance is possible without closing the tunnel to traffic.
SafeSIGNAL
SafeSIGNAL is a visual system for guidance and communication. It is a product developed by Orbipark for Aka PCB, a well established producer of PCBs for 40 years, cooperating with the EU automotive industry. Visit www.aka-pcb.si
SafeSIGNAL is a LED signal light placed on the tunnel walls, similar to Swareflex, that provides better road recognition for drivers. It serves also as a longitudinal measurement of temperature in a tunnel.
It also has an alarm trigger function. There is a control switch on each SafeSIGNAL light installed every 15-20 metres within the tunnel for individual activation of the alarm in case of emergency. The flashing of lights through the whole length of the tunnel can alert drivers about changes in traffic conditions and help prevent a traffic jam. In this mode, the alarm is activated at the spot of the accident, all diodes are flashing to warn other cars in the tunnel to stop immediately.
The product, however, did not enter the production stage.
SafeVENT
SafeVENT is a product developed by Josip Pavetic & Sons, an established Croatian producer of industrial ventilation systems and jet fans for 35 years. Their jet fans are working in more than 80 countries. Visit www.ekovent.hr
One of the advantages of SafeVENT is when a fire breaks out. At that time ventilation apertures in front and behind the fire open and create air curtains. Air curtains isolate smoke to the fire zone, where it is additionally cooled and automatically extinguished. SafeVENT also keeps the area between the portals and the fire zone clear of smoke. SafeVENT creates air curtains, reduces air movement in between, isolates the smoke and fire in the fire zone, and mixes cold air with smoke in order to reduce damage to the tunnel.
SafeHYDRANT
Current fire extinguishing equipment in tunnels is insufficient. The consequence when a fire erupts is
casualties, repair expenses and economical loss. The integrated fire extinguishing system SafeHYDRANT includes the first extinguishing system with TLA hydrant.
TLA hydrants for public and professional use in tunnels are using special multi-purpose nozzles, special light tube (25 mm) that do not fold and additives for best performance. The product was developed and is now produced in Austria by Rosenbauer. Visit www.rosenbauer.com
Bonpet is a nother primary fire extinguisher effective against A, B and C classes of fires and which is most suited for confined spaces. The effective area of Bonpet is about seven square metres. The solution in the ampoule of Bonpet is a unique patented technological breakthrough. When it comes in touch with the fire, the liquid cuts the supply of oxygen to the fire place, cools the surroundings, extinguishes the fire by water vapour it generates. Bonpet is activated in all climatic conditions except
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