ASME-Landmark:Holland Tunnel Ventilation System

The Holland Tunnel, connecting New Jersey and Manhattan, was the first long underwater tunnel in the world designed for motor vehicle use and was built from 1920 to 1927. The 29.5-foot-diameter, 8,500-foot-long twin tubes of this tunnel were shield-driven by the pneumatic method through extremely difficult river-bottom conditions that were overcome by the ingenuity and determination of its engineers, Clifford M. Holland, Milton H. Freeman, and Ole Singstad. They were the largest in the United States when built. The unprecedented length was a bold step forward in subaqueous tunnel engineering.

The principal feature of the cast iron-lined tunnel is the ventilating system. Its design was based on elaborate theories of physiological and mechanical tests conducted mainly by the U.S. Bureau of Mines. The resulting system has been the model for all succeeding vehicular tunnels.

In the Holland Tunnel's transverse-flow system, fresh air is drawn from the outside through one of four ventilation buildings and blown by fans into a fresh air duct located under each tunnel roadway. The air enters the tunnel proper through narrow slots just above the curb, spaced 10 to 15 feet (3 to 4.5 m) apart. Exhaust fans (also located in the ventilation buildings) pull the exhaust-laden air through openings in the ceiling into an exhaust duct located above the ceiling slab, and discharges it into the open air through the roof of one of the ventilation buildings.

The four ventilation buildings (two in New Jersey and two in New York) house a total of 84 fans, of which 42 are blower units, and 42 are exhaust units. They are capable, at full speed, of completely changing the tunnel air every 90 seconds. See ASME website for more information