The Manawatu Herald. Tuesday, August 13, 1912. UNACCOUNTED-FOR GAS.

Manawatu Herald, Volume XXXIV, Issue 1082, 13 August 1912, Page 2

The Manawatu Herald. Tuesday, August 13, 1912. UNACCOUNTED-FOR GAS.

In the gas manager’s monthly reports to the Council there appears large quantities of gas unaccounted for. For instance, in the report provided last night for the monthly period, 330,000 It. was reported as manufactured, and 10,000 odd ft. unaccounted for. A loss, roughly, of 3 per cent, of the total manufactured. Such leakage is beyond the comprehension of most people, and as a result, the manager comes in tor some adverse

criticism. A leakage of gas to the extent of 3 per cent, is not considered abnormal by expert gas engineers. The large quantities unaccounted tor this and last month were due, in great measure, to the two conflagrations, and such shortage may not be recorded again, at least under normal conditions. We have before us a text book on the constitution and management of small gas works, written by Norton H. Humphreys, Assoc. M. Inst. C.E., F.C.S., in which the subject of unaccounted-for gas is dealt with at length. The expert we have named says matters that directly affect the loss are extravagance at the works, waste or excess of schedule quantity for the public lighting, mileage of mains, number of services and meters, and the percentage of meters that show a consumption of less than 1000 ft. per quarter. He suggests that by working on certain lines laid down that the leakage should be kept below xo per cent. More leakage takes place than might be supposed owing to the fact that gas is completely deodorised in some kinds of soil. If a crack or puncture exists, the leakage is continuous for 8,760 hours per annum. A respectable pin-hole will pass one cubic foot per hour, so it is evident that a very small fault will get rid of 10,000 cubic feet per annum. There is also a loss or deficiency between the quantity of gas measured at the works meter and the aggregate of the consumers meters even if the mains are bottle-tight, and all the meters correct, due to the difference in temperature. The average temperature at the consumers’ meters will be less than at the works meter. Gases expand nearly one per cent in bulk for a rise of five deg. Fahr. in temperature, and, therefore, 1,000 cubic feet at 70 deg. will only measure out at 990 at 68 deg. and sojm. With due care —particularly in regard

to the street lamps and economy at the works, the loss should not and in fact has not averaged more than i Yz to 2 per cent., and with the present capable administration there should not be any cause for adverse criticism under this head.