The hose at these hydrants should be festooned on a row of pins,
or doubled on some of the reels made especially for such purposes.
Stand-pipes are not recommended to be placed in rooms or on
fire-escapes; and inside hydrants should not be attached to the vertical
pipes supplying automatic-sprinklers.
Fire-pumps are generally too small for the work required of them, 500
gallons per minute being the minimum capacity recommended. For a
five-story mill there should be an allowance of 250 gallons per minute
for an effective stream through a 1-1/8-inch nozzle, and for lower
buildings the estimate should rarely be less than 200 gallons for each
stream.
Contrary to the general assumption, a ring nozzle is not so efficient as
a smooth nozzle, the relative amount of discharge of ring and smooth
nozzles of the same diameter being as three is to four. For stand-pipes
7/8-inch nozzles are recommended, but for yard hydrant service the
diameter should never be less than one inch, and 1-1/8 inches generally
fulfils the conditions of best service.
The yard hydrants should be placed at a distance of fifty feet from
buildings, and covered with a house which should also contain hose,
axes, bars, nozzles and spanners.
Water-mains about a mill-yard should be of ample capacity not to cause
an excessive loss by friction, their diameter being based upon a limit
of velocity of ten feet per second for the maximum delivery.
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