Spring Valley Water Company, San Francisco.
following figures, * given in tabular form, show the details of the
construction of an 18-inch wrought-iron pipe, 5,800 feet long, made for
the Spring Valley Water Company, which supplies the city of San
Francisco. This pipe has a tensile strain of about 5,000 or 6,000 lbs.
per sectional inch, and was made with this low coefficient in order to
withstand the pulsations caused by a single-acting plunger pump making
as high as 36 (four-foot) strokes per minute. These pulsations in
practice vary from 5 to 9 lbs. per stroke when the air-vessel is
properly charged, but through carelessness they may exceed 50 pounds.
* Details by Joseph Moore, Superintendent of the Risdon Iron-Works, San Francisco.