WATER MAINS

Wairarapa Times-Age, 24 April 1940, Page 11

WATER MAINS

RELINING PROVES HIGHLY SATISFACTORY OVERCOMING INCRUSTATIONS. EXPERIENCE AT AUCKLAND. ‘’Tests of city water mains to determine the pressures and rate of flow, following the scraping and relining with cement, of the pipes; are now being carried out in the Parnell area,” states the “N.Z. Herald” of October 5. 1938. "This work has been going on in various parts of the city and suburbs for the past two .years; and the City Waterworks Engineer (Mr A. D. Mead) has had tables prepared showing the results of the investigation. REDUCTIONS IN CAPACITY. “After scraping and cleaning of the mains a coating of cement is forced into the pipes under pressure, and this has given a smooth bore which not only accelerates the flow of water, but is calculated to give the old cast iron mains a further life of usefulness, of 50 years or more. “It was found that some of the older mains in the residential areas, and which have been in use for up to 55 years, were so encrusted that their capacity was reduced by about 50 per cent; but this capacity had been almost wholly restored by the new Tate process treatment. “The Waterworks Engineer has shown that, for ordinary domestic purposes. the pressure should not be below 401 b oi- above 801 b to the square inch; as lower pressures give an unsatisfactory service, and higher pressures are apt to cause water-hammer and rapid leakage of washers. A minimum flow of 200 gallons a minute is considered effective for fire-fighting in these areas, although a good deal more is necessary in commercial areas.

INCREASING DEMAND. “In the residential localities so far i dealt with and tested, the lowest pressure recorded was 501 b. Prior to treatment by the Tate process the flow showed an average of 170 gallons a minute, whilst the recent tests give an average of 278 gallons, which can be regarded as highly satisfactory. “The increasing demand on the water supply in the Parnell and other suburban areas is approaching the capacity of the chief distribution mains in the city, and Mr Mead has recommended the replacement, or reconditioning of a number of sections at an estimated cost of £23,600, and the scraping and relining of 44 miles of mains, in Grey Lynn, Archhill. Newton and Eden Terrace, Grafton, part of Epsom and part of Remuera —at a cost of six hundred pounds (£600) per mile, and for which purpose in view, the Auckland City Council has decided to make provision—in the next Loan proposal—for the raising of fifty thousand pounds (£50,000) to carry out these works.” QUESTIONS AND ANSWERS 17. Q.: Is the process of lining the pipes in situ, a complicated one? A.: No. on the contrary, it is fairly simple. A ‘movie’ picture, illustrating the whole process, will be shown at the public meeting (to be held in the Municipal Hall) on Thursday evening. May 2. 18. Q.: If the loan is carried, will the work be proceeded with, before next summer? A.: Yes. it must be done during the winter months, while the pressure is sufficiently high to enable the town to be supplied by one main, while the other is being lined. In this respect we are. as a Borough, fortunate in having two mains enabling us to do this without undue interruption of the supply. (To be continued).