Tunnel ventilation
Tunnel ventilation is the ventilation of a tunnel structure or a tunnel-like structure in order to divert the pollutants emitted in the tunnel space - for example by cars - and replace them with fresh air. Another aspect is the smoke extraction of tunnels to save lives.
historical development
In the early days of tunnel system construction, half- transverse ventilation was planned for medium-length tunnels , full transverse ventilation was planned for longer tunnel lengths, and subsequently combined half- transverse full transverse ventilation was also planned. Axial fans are used in these types of tunnel systems .
At the beginning of the second half of the 20th century, the development of individual components for tunnel ventilation systems ran parallel to the development of fans for thermal power plants, mine ventilation systems in the mining sector and wind tunnel systems. The problem with the conception of the systems was the inclusion of parameters, some of which could not be clearly foreseen, such as an increase in the volume of traffic, expected pollutant emissions and fresh air demand.
More recently, longitudinal ventilation systems have been installed, especially in tunnels up to three kilometers long. Longitudinal ventilation systems have lower investment, operating and maintenance costs compared to other systems. In longitudinal ventilation systems, jet fans, also known as jet fans, are used, which are installed individually or in groups at certain intervals on the tunnel ceiling. The distance between the fans is chosen so that an optimal mixing of the propulsion jet with the rest of the tunnel flow and a good flow distribution in the tunnel cross-section is guaranteed.
conditions
The tunnel ventilation system is determined based on the respective conditions of the tunnel structure. In addition to the length of the tunnel, the decision-making criteria for the conception are, in particular, the need for fresh air depending on CO, NO x and cloudy emissions, as well as the longitudinal speed of the tunnel, taking into account applicable legal regulations and guidelines.
In order to comply with the prescribed immission values in the tunnel, the fresh air and exhaust air flow must be continuously adapted to the current traffic conditions. Different control options are used to adjust the volume flow. The fans are speed-controlled with the option of hydraulically adjusting the blades.
Tunnel ventilation systems are also important in the event of fire. The requirements and dimensioning, the fire ventilation concept and the temperature resistance of the ventilation system are regulated in the guidelines for the equipment and operation of road tunnels (RABT). For example, exhaust fans and exhaust flaps, with the help of which smoke is extracted from the driving area , must be designed for a temperature resistance of at least 400 ° C with at least 90 minutes of functionality.
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Free / natural ventilation
Tunnel systems are usually designed and built in such a way that free ventilation , i.e. ventilation through natural thermals or wind loads, is always guaranteed. Cross ventilation is the most common form of ventilation in short tunnels. Above-ground tunnel systems usually have roof attachments or skylights through which the roof attachment ventilation or window ventilation is implemented.
Tunnel ventilation
Tunnels are mostly underground structures that always have to do with moisture, temperature differences (condensation) and pollution. The ventilation of a tunnel through a ventilation system thus serves on the one hand to dehumidify the tunnel structure and on the other hand to improve the breathing air quality. Since some tunnels are a few kilometers long, it is important for every car or truck driver to be able to permanently suck in fresh air through their own vehicle ventilation system and not to suffocate in the exhaust gas flow.
In the case of tunnels ventilated with compressed air, there is often no need to install an exhaust air system, as the incoming air displaces the polluted air into the open air via the tunnel exits and risers (displacement ventilation).
Tunnel ventilation
The targeted ventilation of a tunnel system is used for the targeted removal of contaminated room air from the tunnel. The room air is sucked in from the tunnel via riser shafts and exhaust air fans and blown outside above ground.
In the case of ventilation in a tunnel system with negative pressure, the air supply system is dispensed with, as the air can flow freely through the tunnel entrances.
Tunnel smoke extraction with flue gas fans
In the event of a fire, flue gas fans are used to discharge the smoke from a tunnel system as quickly as possible, during a fire or after a fire, in order to protect the victims or the helping rescue personnel from smoke poisoning. These flue gas fans can be installed directly in the tunnel, on the ceiling / wall, or as supply air or exhaust air fans at the entrance or exit of the tunnel system. The main focus of this special type of fan is thermal resistance and thus reliability even at higher exhaust air temperatures.
Tunnel smoke extraction via riser shafts with fans and flaps
Another possibility for smoke extraction from tunnels is riser shafts. The shafts for the smoke extraction fans are preferably arranged on the tunnel ceiling and across the tunnel axis in order to safely remove all fire and smoke gases from the tunnel.
Tunnel-like structures
The overall conception of tunnel ventilation also applies to underground garages, multi-storey car parks and garages and is achieved using mechanical ventilation systems and smoke extraction systems. But also with large animal farms or the fattening of animals in tunnel-like buildings, the technical standards and experience of tunnel ventilation for rail and car traffic are taken into account.
Regulations and standards
- RABT [2003] Guidelines for the equipment and operation of road tunnels
- VDI 6029 [2000-03] Ventilation systems for road tunnels
- DIN EN 12101-3 [2002-06] Keeping smoke and heat free - Part 3: Regulations for mechanical smoke and heat exhaust ventilation devices
- Directive 2004/54 / EC Directive on minimum safety requirements for tunnels in the trans-European road network
- PIARC standard part 1 / part 2
- NFPA 130 - Standard for Fixed Guideway Transit and Passenger Rail Systems
- NFPA 502 - Standard for Road Tunnels, Bridges and Other Limited Access Highways
See also
literature
- Page no longer available , search in web archives: tunnel ventilation - WITT & Sohn. (PDF; 2.3 MB) In: wittfan.de
- Safety first, road tunnels in Germany. (PDF; 11.4 MB) In: strassenbau.niedersachsen.de. Retrieved August 10, 2018 .
- Correct behavior in the road tunnel. (PDF; 568 kB) In: strassenbau.niedersachsen.de. Retrieved August 10, 2018 .
- Tunnel ventilation. In: Viktor von Röll (ed.): Encyclopedia of the Railway System . 2nd Edition. Volume 9: Seaport tariffs - transition curve . Urban & Schwarzenberg, Berlin / Vienna 1921, pp 432 -437.
Web links
- Fire protection for the underground car park, multi-storey car park and tunnel with the thrust fan. In: colt-info.de. Retrieved September 18, 2013 .
- Air for the underground traffic arteries. In: howden.com. Retrieved September 18, 2013 .
- The World Road Association (AIPCR / PIARC). FGSV - Research Society for Roads and Transport, archived from the original on July 18, 2009 ; Retrieved September 18, 2013 .
Individual evidence
- ↑ Tunnel smoke extraction with fans and flaps. (PDF; 621 kB) In: tunnellueftung.de. Retrieved September 18, 2013 .
- ↑ European standard DIN EN 12101 and with applicable standards. In: baunormenlexikon.de. Retrieved September 18, 2013 .
- ↑ Directive 2004/54 / EC of the European Parliament (PDF; 512 kB), accessed on September 18, 2013 .
- ↑ Standard NFPA 130 from 2000 contains requirements for fire protection. (PDF; 2.5 MB) In: traffgo-ht.com. Retrieved September 18, 2013 .
- ^ NFPA 502 Standard for Road Tunnels, Bridges, and Other Limited Access Highways 2004 Edition. In: de.scribd.com. Archived from the original on September 21, 2013 ; Retrieved September 19, 2013 .