Mechanical ventilation of tunnels is costly because of the initial installation and the continued maintenance and operation. However, at some tunnel length corresponding to a particular altitude, traffic configuration and topography there is a need for this forced ventilation. This study was undertaken to help determine the pollution concentration in existing tunnels in Colorado, and predict the length of tunnels which will need mechanical ventilation. The study indicated that, even at high altitudes, tunnels will vent very well when the length is less than 2000 feet and traffic is less than 1500 vph. Above these limits, combinations of increased length and increased traffic may require some type of mechanical ventilation for tunnels serving vehicles with internal combustion engines similar to those used today. The greatest pollution concentration condition occurs when vehicles are stopped and engines continue the "idle." When vehicles are in motion the induced wind will be approximately 7 mph and contribute significantly to the dispersion of pollutants.

  • Corporate Authors:

    Colorado Department of Highways

    4201 East Arkansas Avenue
    Denver, CO  United States  80222
  • Authors:
    • Gerhardt, B B
    • Donnelly, D E
    • Griffin, R G
    • LaForce, R F
  • Publication Date: 1973-9

Media Info

  • Pagination: 69 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00263005
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Report/Paper Numbers: Final Rpt.
  • Contract Numbers: 1473
  • Created Date: Sep 5 1974 12:00AM