Enclosed Vehicular Facilities
ASHRAE Technical Committee 5.9

Scope of TC 5.9

TC 5.9 is concerned with existing technology and design requirements for enclosed transportation facilities. Enclosed vehicular facilities encompass the subway portion of rapid transit systems, vehicular tunnels, rail tunnels, enclosed bus ways, bus terminals and parking garages.


The ASHRAE Handbook is published in a series of four volumes, one of which is revised each year, ensuring that no volume is older than four years.

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TC 5.9 is responsible for Chapter 16 in the ASHRAE HVAC Applications Handbook volume:

Enclosed Vehicular Facilities
Enclosed vehicular facilities include buildings and infrastructure through which vehicles travel, are stored, or are repaired, and can include vehicles driven by internal combustion engines or electric motors. Ventilation requirements for these facilities are provided for climate and temperature control, contaminant level control, and emergency smoke management. Design approaches for various natural and mechanical ventilation systems are covered in this chapter. The chapter is structured to address general tunnel issues first and then address the unique aspects of rail and road tunnels, rail stations, bus garages, bus terminals, and enclosed spaces for equipment maintenance later in the chapter. Finally, information on applicable ventilation equipment is presented.

This chapter contains the following sections:

  • - Tunnels
  • - Parking garages
  • - Bus garages
  • - Bus terminals
  • - Tollbooths
  • - Diesel locomotive facilities
  • - Equipment
  • - National and international safety standards and guidelines 

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ASHRAE writes standards for the purpose of establishing consensus for: 1) methods of test for use in commerce and 2) performance criteria for use as facilitators with which to guide the industry. ASHRAE publishes the following three types of voluntary consensus standards: Method of Measurement or Test (MOT), Standard Design and Standard Practice. ASHRAE does not write rating standards unless a suitable rating standard will not otherwise be available. ASHRAE is accredited by the American National Standards Institute (ANSI) and follows ANSI's requirements for due process and standards development. Standards may be purchased at the ASHRAE Bookstore.

TC 5.9 is cognizant for the following standard:
Standard 217: Non-Emergency Ventilation in Enclosed Road, Rail and Mass Transit Facilities

Other Activities

TIP: If MTG involvement add here otherwise leave blank.



ASHRAE Technical FAQs are provided as a service to ASHRAE members, users of ASHRAE publications, and the general public. While every effort has been made to ensure their accuracy and reliability, they are advisory and provided for informational purposes only, and in many cases represent only one person’s view. They are not intended and should not be relied on as an official statement of ASHRAE. Technical questions not addressed may be submitted to the ASHRAE Technical Services department at tse@ashrae.net.