415, 0.295, and 0.177 cubic foot per mile per hour. By calculation,
the volume of acetylene generated in this village would appear to have
been about 23,000 cubic feet per mile of main per year, and therefore it
may be said that the proportion of gas lost was reduced by attending to
the cocks from 15.7 per cent, to 11.3 per cent, and then to 6.8 per cent.
At another village where the main was 2.5 kilometres long, tests
extending over two months, when the public lamps were not in use, showed
the leakage to be 4.4 litres per kilometre per hour, _i.e._, 1.25
cubic foot per mile per hour, when the annual make was roughly 46,000
cubic feet per mile of main. Here, the loss, calculated from the direct
readings of the works motor, was 4.65 per cent.
When all the fittings, burners excepted, have been connected, the whole
system of pipes must be tested by putting it under a gas (or air)
pressure of 9 or 12 inches of water, and observing on an attached
pressure gauge whether any fall in pressure occurs within fifteen minutes
after the main inlet tap has been shut. The pressure required for this
purpose can be obtained by temporarily weighting the holder, or by the
employment of a pump.
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