CAR TUNNEL’S 29 FANS

Poverty Bay Herald, Volume LIX, Issue 17919, 25 October 1932, Page 7

CAR TUNNEL’S 29 FANS

VENTILATION UNDER MERSEY CARBON MONOXIDE DEFEATED LIVERPOOL, Sept. 5. How is it possible to ventilate a tunnel through which motor vehicles can pass at the rate of 3000 an hour, each journey occupying 8} minutes? The development of motor transport has brought with it a great many new problems, but none more striking perhaps than the one now being tackled at Liverpool, where, at a cost of £7,000,000, a new tunnel has been driven below tho River Mersey, between Liverpool ami Birkenhead, the longest umler-water tunnel in tnd world. The tunnel hits been driven to a depth of 170 ft., and to withstan I tho enormous pressure it was essential to make a circular cutting so big that its internal diameter is 44ft. When tho tunnel was started seven years ago less .was known than now about the kind of ventilation requisite when hegvy motor traffic is passing through. Carbon monoxide, of course, was the great enemy. Nobody at the outset knew exactly what proportion of carbon monoxide in the air was fatal, or what proportion could be borne by a human being without any deleterious effects. Nor did anybody know exactly how much carbon monoxide was given off per hour by a motor-car or lorry. . ■ The result of experiments proved that the best method of ventilation was 1o use the whole of the open tunnel above the roadway as the exhaust duct. It is this system that is being installed. Six ventilating buildings are being built, three on each side of tho river, and in those the blowing and exhaust fans are to be housed. Twenty-nine fans aro to bo provided, but. about half of them are for use only in emergency. Normally nine blowing fans and six exhausting fans will operate. It is confidently believed that the ventilation problem has been solved in the most satisfactory way, and that within 12 months the tunnel will be opened.