Investigations About Methods to Control Airflow in Road Tunnels (original) (raw)

For road tunnels with and without smoke extraction, the control of longitudinal airflow is essential in order to limit smoke propagation in case of fire. Various concepts for the handling of longitudinal airflow have been investigated. These include jet fans, the use of (semi-)transverse ventilation, directed point air injection (Saccardo-nozzles), local air extraction, air curtains and mechanical curtains. At present, the application of jet fans is the standard solution, but not necessarily the optimum for all applications. Jet fan installation in the traffic envelope often leads to problems with corrosion and accessibility for maintenance and repair. Jet fans require extra space under the ceiling or in niches. This may lead to high additional costs if jet fans have to be retrofitted during ventilation system upgrades in existing tunnels. Particular attention is paid to the rededication of existing supply air ducts in tunnels with transverse ventilation systems. Many tunnels of med...