TUNNEL KASTELEC - PLANING, REALISATION, TESTING, EXPERIENCES

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1 TUNNEL KASTELEC - PLANING, REALISATION, TESTING, EXPERIENCES ABSTRACT prof.dr. Jurij MODIC dr. S. Muhič, dr. C. Arkar Faculty of Mechanical Engineering Ljubljana, Slovenia Slovenia is among the European states with a considerable number of road tunnels. Two relatively new tunnels are on the road from Ljubljana to the Adriatic seaside: Kastelec and Dekani. Both tunnels have a similar design and therefore the Kastelec tunnel only is introduced here. The length of the tunnel is 2180 m, with a constant gradient of 2.5% towards south and with variable traffic mix. Strong winds of up to 130 km/hr have been recorded in the area and this condition has been emphasized in the design. Plans for the tunnels were made several years ago by the government and they were ultimately built in 2002, opening for traffic in A longitudinal ventilation system was designed and built with 14 jet fans installed in each tube. In case of a tunnel fire, the non-incident tunnel will be used for rescue. To enhance the ventilation in the incident tunnel, the fans are blowing air in the same direction in the rescue tunnel, while smoke is exhausted from the tunnel with a vehicle fire. The fans in both tunnels are reversible and have the capability of switching from one direction to the other. Keywords: ventilation design, fire safety, 1. INTRODUCTION Analysis treats of traffic circumstance at normal traffic and at congestions in instance of oneway traffic in tunnels Kastelec and Dekani. Main accent in study is on simulation of fire in some zones of tunnels at one-way traffic at fire 100 MW. At this are calculated and simulated speed and temperatures of air, surface temperatures of walls, times, retreat from fire zone requires him and time, inclusion of fans requires him. Against this are of remembered also of demand in neighborhood tunnel tube, that he serves for rescuing in case of fire. Finally study is slacked also analysis of necessary fire safety measures, of necessary for ensuring of safety of traffic and of health and lives of participants in traffic. In first part of analysis are calculated and simulated concentrations of harmful substances (carbon monoxide, nitrogen oxides and concentrations of solid particles) at foreseen traffic circumstances, where is remembered number driven 2000 h -1 and 15% share of trucks, namely at various speeds of ride. Results of calculations are showed in tables, and diagrams. In other part of analysis is done simulation of fire in various zones of tunnel, power 100 MW. Basic calculations are straight so slacked in supplement. In the analysis is remembered above all power of fire 100 MW, because is likelihood 300 MW fire minimal. Results are handed in shape of tables, and for every fire zone especially. Likewise are more in detail treated circumstances of pressure and velocity in neighborhood of tube, which he serves as rescue tunnel in case of fire. Also wind speeds are considered at this.

2 SIMULATION IN TUBE KASTELEC 2.1. Kastelec 1 (left tube) Situation On Fig. 1 are showed main dimension and schedule of fans in tunnels Kastelec, including rescue crossing passages, between which is distance cca 400 m. Zone are showed likewise, in which is simulated fire. In left tube is this from first of left zone (KLZ1) to sixth of left zone (KLZ6), in right tube from KRZ1 to KRZ6. Mark means: K - Kastelec, L - left, D right, Z - zone, and the number m m 300 m LEFT TUBE Kastelec m 1800 m 1900 m 2000 m LJ KLZ1 KLZ2 KLZ3 KLZ4 KLZ5 KLZ6 Gradient +2.5% cca 400 m 700 m 1100 m 1400 m 1800 m cross passages RIGHT TUBE Kastelec 2 KRZ1 KRZ2 KRZ3 KRZ4 KRZ5 KRZ6 KP 150 m 2260 m 2100 m Fig.1: Fans, fire zones and rescue crossing passages For prognosis of traffic for year 2015 is foreseen maximum density of traffic 2340 h -1, take in account as value 2000 h -1 (15% of trucks) Concentrations Of windy circumstance at tunnels Kastelec are special. Round meteorological data are 60% days with wind, which speed is smaller from 10 m/s (36 km/h), 85% days with speed smaller from 12 m/s (44 km/h), and 8% days with wind speed over 30 m/s (110 km/h). This wind is very changeable and pushing (Fig. 2). Of speed of air in (m/s), and of concentration of carbon monoxide CO (mg/m 3 ) and nitrogen oxides NOx (µg/m 3 ) are simulated for various speed of ride, without of wind, for wind, speed 30 m/s, at included, and at excluded fans. Fans are estimated because of comparatively large inclination (gradient), above 2.5 % because of fire safety. We can see, that at driving velocity under 5 km/h the fans are not enough, it is necessary to switch of the engines of vehicles.

3 MODEL OF WIND Velocity (m/s) Time (min) Fig 2: Model of wind (tested!) Table 1: Concentrations in Kastelec 1 Kastelec 1 No wind Wind (average maximum) v (km/h) u (m/s) CO mg/m 3 NOx µg/m 3 u (m/s) CO mg/m 3 NOx µg/m 3 0 (no fans) (fans) (no wind) (fans) (no fans) (fans) (no fans) (fans) (fans) (no fans) (fans) (no fans) (fans) AIR VELOCITIES 3.1. Velocities in Kastelec 1 We simulated 4 cases see Fig. 3): Fans no (off) wind no (off) Fans no (off) wind no (off) Fans yes (on) wind yes (on) Fans no (off) wind yes (off) Fn Wn Fn Wn Fy Wy Fn Wy

4 KASTELEC 1 - air velocities Air velocity (m/s) Driving speed (km/h) Fn Wn Fy Wn Fy Wy Fn Wy Fig.3: Air velocities in Kastelec 1 (100% traffic) The air velocity in tunnel is also a function of density of traffic (Fig. 4). AIR VELOCITY (1) 6 4 AIR VELOCITY (m/s) % 20% 30% 40% 50% 60% 70% 80% 90% 100% TRAFFIC (%) Wmax v100 Wmax v60 Wav v100 Wav v60 Fig.4: Air velocities in Kastelec 1 (various traffic) 4. FIRE SIMULATION 4.1. Fire in Kastelec 1 KLZ Generally In tunnel Kastelec 1 we made simulation of fire 100 MW in 6 examples. Calculation of speed of air is simulated at excluded and at included fans (including time: cca 10 minutes). As example is here showed case of fire in KLZ Air velocities Table 2: Air velocities in case of fire (no wind) Off (m/s) On (m/s)

5 At excluded fans is the air speed speed enough low that is not too large cooling off smoke, at included fans are high enough, to cleaning tunnel from smoke Air temperatures Table 3: Air temperatures in case of fire (no wind) Off (m/s) On (m/s) Because of excluded fans are against flash over of fire the temperatures of air several high, however it is important, that speed of air stay low enough. That is why temperatures also several located are. When for cca 12 minutes start up fans, temperature of air is going quickly to lower, however they are alongside tunnel, for difference from before several more highly Rescue tube (Kastelec 2) Generally At double tunnels we have in case of fire tube with fire and rescue tube, through which move away participants of incident from tube, where fire is. We must prevent entry of smoke to rescue tube and in her to ensure current of fresh air, which means, that must in rescue tube to ensure overpressure. On this way we prevent also entry of smoke to rescue tube. This can achieve on two ways: classical procedure new perfected procedure 2320 m m 300 m 1700 m 1800 m 1900 m 2000 m LJ INCIDENT TUNNEL Kastelec 1 I H G KLZ5 F E D C Gradient +2.5% cca 400 m 700 m 1100 m 1400 m 1800 m cross passages A NON INCIDENT TUNNEL Kastelec 2 B KP 150 m 2260 m 2100 m Fig. 5: Fans in case of fire (example for KLZ 5) Classical procedure At the beginning of fire, in incident tunnel the air velocity should be 1 2 m/s. The fans must be switched of for cca 10 minutes. In non incident tunnel we switch on the couple of fans A and B. So is in the middle of this tunnel an over pressure: 39 Pa

6 After minutes we switch on the fans C, D, E, F, G, H and I, in incident tunnel is an under pressure. But it is a danger to come smoke in the non incident tunnel. It depends on form and some other properties of portals, meteorological circumstances, New improved procedure At the beginning of fire we switch on the fans B in the opposite direction. In non incident tunnel is an over pressure. After 10 minutes we switch on the fans G, H and I in the same direction, as fans B. So is an over pressure in non incident tunnel, and an under pressure in incident tunnel. Direction of air movement in both tubes is the same; the smoke can not come in the non incident tunnel. 5. TESTING 5.1. Fire testing Generally Goal of found out of test was to find out temperatures and velocities in intersection of tunnel against over flash of fire. This was simulated with prescribed quantity two different fuels. Besides evaluating of process was goal measurement also indirect compare of built-in felt and of warning systems. Simulation of fire was found out in left tube of tunnel Kastelec on location first niche, where is made also crossing passage for connection between both tubes. Pools for fuel were placed some meters for niche in middle of tunnel. Two pools were used (round and in shape letter X). In middle over both wares was located construction with four plates namely in plain of intersection of tunnel, as shows Fig. 6. Fig. 6: Plates with temperature sensors (T1 T5)

7 Temperatures temperatura ( C) čas (min) T1 ( C) T2 ( C) T3 ( C) T4 ( C) T5 ( C) By calculation: T1 = 176 ºC Fig. 7: Temperatures in Kastelec Temperatures measured by IR camera Fig. 8: Thermo grams in Kastelec 1 (example) Conclusion Found temperatures and of speed of movement of air can serve for comparison with measured values of built-in felt and theoretical simulation models. For estimating most highly temperature of air in tunnel in case of fire at further tests necessary to accompany also longitudinal temperature gradient. It turns out, that is deviation of flame in connection with air moving. That is why are of temperature in vertical plain over flame more lowly, highest measured temperature is consequence of counter flow of flue gases underneath rim of tunnel. We estimate against this, that speed of air in intersection of tunnel longitudinal isn t changing essentially. Between fire also didn't find of important changing of speed of air. Essentially are growing up only round start of fans. 6. CONCLUSION Density of traffic is very changeable so in winter time, in the middle of week, traffic is very rare, in touristy season; guest is at weekends especially exceptionally, even congestions are occurring. Inclination (ascent and fall) is for high way tunnels relatively large, because amounts ±2.5%, which means, that is between portals cca 60 m of high-altitude difference. Consequence of this is prominent buoyancy.

8 Both tunnel Kastelec are emphasized very strong north wind (bora), which considerably influences on hydraulic circumstance in tunnel, by ventilation, but also in case of fire and against occurring of fog. Because of vicinity of port Koper be probably guest traffic of cisterns with gasoline against interior of Slovenia, which in considerable measures influences on fire endangerment of tunnel. There is danger of occurring of fog in tunnels because of changeable windy and temperature circumstances. At ventilation distinguish four different instances: 1. Ventilation in normal conditions 2. Ventilation against strong wind 3. Ventilation in case of fire 4. Ventilation to prevent a fog in tunnel At normal conditions in all tunnels show results of simulation, that in case of congestion fans is not enough. This means, that it must put out car engines in this instance, or to stop traffic. At speed of ride 5 km/h and more fans not even are not necessary. In case of strong wind and at excluded fans at low speeds of ride appears negative speed of air, which is not wrong, because tunnel cleans in inverse direction, and it is concentrations of harmful substances in speed limits. The drivers must put out engines at congestion of traffic in tunnel, because otherwise tunnel can't be clean. At speeds of driving over 5 km/h tunnel is ventilated alone, either because of piston effect, either because of buoyancy as consequence comparatively ascent (or of fall), either because of wind, or because of activity of fans. In case of strong wind and at excluded fans in some instances appears negative speed of air flow, that he helps with lowering of concentrations of harmful substances straight so, although to opposite direction. Because are all this phenomena between self interwoven, and it is heavy to foresee every situation separately, we must use the automatics. Sensors must find level of concentration of harmful substances, also direction and strength of air flow in tunnel. When level of concentration of harmful substances achieves admissible value, must with fully power include all fans, direction of rotation or direction of air flow must to be harmonious with direction of natural movement of air, irrespective of direction of traffic. We must stop fans in case of fire at once. In instance, when is not a strong wind, this is enough. If the wind is blowing, must with all power to start up fans against direction of movement of air. In case of strong wind is also in this instance speed of air a bit too high, however acceptable. Round expiry cca 12 minutes must to start up fans with all power, namely in direction of movement of air at stopped fans. With this achieve greater speed of air and greater efficiency at cleaning of tunnel or at extracting smoke from tunnel. 7. REFERENCES 1. A. Bendelius Simulation of Escape from Road Tunnel Using Simulex Tunnel Safety and Ventilation, Graz, K. Pucher The new Austrian Safety Concept In Case of Fire for Road Tunnel with Longitudinal Ventilation, Congress Ljubljana, J. Modic Criterial Number by Natural Ventilated Tunnels Elsevier Science S.A. Dublin, IDA Road Tunnel ventilation Software, Equa Simulation Technology, Stockholm, J. Modic Analysis of Ventilation and Fire Safety in Tunnels Kastelec IBE, Ljubljana, 2005