axial fan

Road Tunnel Ventilation

In a road tunnel, the ventilation has to serve the purpose of securing smoke free escape routes in the case of a tunnel fire by appropriate smoke management and control. In many tunnels, the required air quality in normal operation is often achieved without the operation of a mechanical ventilation system, given the modern fleet of vehicles nowadays in developed countries.
Aerodynamics, thermodynamics and ventilation of underground traffic structures belong to IP Engineering┬┤s core capabilities. As internationally recognized experts in air flow control and smoke management, our staff has profound knowledge and decades of first-hand experience on the best practice of fire safety engineering in underground facilities.

Tunnel Specific Requirements

Beside good engineering practise and the up to date state of technology, standards, laws and guidelines play a major role in the design of ventilation for road tunnels. Such as the German guidelines VDI, the guidelines about equipment of road tunnels RABT and ZTV-ING, the Swiss guidelines SIA and ASTRA for ventilation, the safety manual BSA of the Swiss Federal Roads Office FEDRO (ASTRA), the Austrian road tunnel safety law, the Austrian guidelines RVS, the ASFiNAG design handbook PLaPB, the European Directive on minimum safety requirements for tunnels in the Trans-European Road Network 2004/54/EC, the NFPA and PIARC publications on safety, smoke control and air demand in road tunnels and many other applicable national and international requirements.

Designing the Ventilation Systems

Before a tunnel goes into the construction phase, its intended safety measures design undergoes calculation, simulation and evaluation in every detail. Deep insight into the fundamentals of fluid dynamics and thermodynamics of tunnels is required, the nature of smoke propagation and fire development and the interaction with the tunnel ventilation systems has to be understood. The human behavior, also in panic, has to be taken into consideration. Last but not least all relevant design criteria from BIM building information modelling data, tunnel safety codes, guidelines and standards as well as third party requirements have to be considered to create a safe, stable, reliable and state-of-the-art ventilation system. IP Engineering reliably delivers tunnel ventilation system design from concept to detailed design to tendering to commissioning and testing.

Flow Control in Tunnels

Most fatalities in tunnel fire events have been caused by the spread of toxic smoke. The control of smoke spread is crucial to providing a survivable environment for egress. A properly designed and tuned feedback control loop is required to achieve a target flow which is slow enough to allow for escape of people under different boundary conditions. It is also helpful in optimizing energy consumption under moving traffic conditions. A reliable feedback flow control system requires sophisticated engineering know-how and experience, careful selection of instruments and controlled variables, and a thoughtful implementation from design through field testing and commissioning.

Calculations and Simulations

Where required, all the calculations, modeling and dynamic simulation of the aerodynamics and thermodynamics of complex tunnel ventilation and smoke extraction systems, including the effects of traffic, ambient weather and tunnel fire are carried out.

Procurement Support and Site Supervision

Professional support is provided in procurement and commissioning of plants, conduct factory acceptance tests FAT for fans and dampers, site acceptance tests SAT and fire / smoke tests in the tunnel as your agent, prepare technical specifications and bill of quantities (BoQ) for jet fans, supply fans, exhaust fans, fire-dampers, air-quality instruments, flow state monitors and other ventilation components, elaborate system specification for control systems and assistance in their implementation.


IP Engineering assists in tendering of engineering-, installation- and design-services, components and equipment and, last but not least, deliver independent third-party expert opinion, ventilation design review and specialist counseling - worldwide.

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