Fire & water mist vs. longitudinal ventilation in tunnels

Does the action of a water mist system assist or hinder the action of a tunnel ventilation system, with regard to smoke control? Or, more practically, if a water mist system is activated in a tunnel, are more jet fans required for smoke control, or fewer? To answer this question, a mathematical model was built in MATLAB to balance the many equations relating to thrust, flow, friction, fire size, tunnel size, ventilation flow, water mist effects, evaporation, temperature and heat losses. An example test case is presented. When no fire is present, 3 jet fans are required to generate the desired ventilation velocity for emergency smoke control. The model shows that when a fire is present, but no water mist is active, that larger fire sizes require progressively more jet fans. However, when water mist is introduced into a tunnel containing a fire, more jet fans are required for smoke control if the fire is small, but fewer jet fans are required for smoke control if the fire is large.


  • English

Media Info

  • Pagination: pp 389-403
  • Monograph Title: Proceedings from the Ninth International Symposium on Tunnel Safety and Security, Munich, Germany, March 11-13, 2020

Subject/Index Terms

Filing Info

  • Accession Number: 01845954
  • Record Type: Publication
  • Source Agency: Swedish National Road and Transport Research Institute (VTI)
  • ISBN: 9789189049895
  • Files: ITRD, VTI
  • Created Date: May 20 2022 2:06PM