Implementation of jet fan based longitudinal and semi-transverse ventilation systems

Based on favorable results from the Memorial Tunnel Fire Ventilation Test Program (MTFVTP) conducted in West Virginia, on November 1, 1995 the Federal Highway Administration (FHWA) issued a memorandum authorizing the consideration of jet fan based longitudinal ventilation systems of roadway tunnels on federally aided projects. With regard to the Central Artery/Tunnel (CA/T) Project, potential opportunities for significant cost containment were immediately envisioned through the incorporation of jet fan based longitudinal ventilation systems in lieu of, or in combination with, the currently planned full-transverse tunnel ventilation system on certain project roadways. To that end, FHWA and Massachusetts Highway Department (MHD) initiated the Tunnel Jet Fan Implementation Program to identify candidate project tunnels for longitudinal ventilation. Per direction of FHWA, the physical criteria to be used in the selection of candidate tunnels was established based on similar characteristics as that of the MTFVTP test site, i.e.: Tunnels that have traffic flow in one direction only. Tunnels in the range of 2,000 feet long, or less. Tunnels that service up to two lanes of vehicular traffic. Based on the above criteria, fourteen project tunnels were identified as candidates for analysis as to the potential application of jet fan based longitudinal ventilation systems.