A number of tests of the Memorial Tunnel Fire Ventilation Test Program were devoted to determining the effectiveness of a full-transverse ventilation system in limiting the spread of smoke and hot gases, with varying system configurations and air flow rates. The controlled fire, located at the approximate quarter point of the 2,800ft (854m) long tunnel, was varied in three levels of intensity; 10, 20 and 50 megawatts (MW). Heavily insulated instrument "trees" at fixed cross-sectional locations throughout the roadway and in the plenum above the ceiling were equipped with thermocouples, bidirectional pitot tubes, and gas sampling tubes. The data-acquisition system (DAS) in a control trailer remote from the tunnel continuously recorded air temperatures, air velocities, and gas concentrations for subsequent analysis. A closed-circuit television (CCTV) system, composed of seven cameras inside the tunnel and immediately adjacent to its portals, facilitated observation of smoke movement at the monitors, which were also located in the control trailer. A total of 19 full-transverse tests were conducted - 9 with balanced supply-exhaust air flow rates and 10 with an imbalanced system configuration in which the exhaust flow rate exceeded the forced supply flow rate, causing the make-up air to be introduced through the tunnel portals. Addresses results and conclusions drawn by the author on the basis of acquired data and observations as an eyewitness to these tests as a member of the joint test group.

Units: Dual

KEYWORDS: year 1997, Testing, smoke ventilation, fire, tunnels, USA, comparing, roads