The Insurance Companies have issued detailed specifications for the
construction of fire pumps to be known as Underwriter Fire Pumps.
They have agreed that such pumps with their specified attachments be
recognized as the approved type, and that pumps built and fitted up
less perfectly be not approved in future installments.
_The wide experience and systematic methods_ of the Insurance Companies
place them in position to give valuable suggestions as a result of
their observation and experiment, and these are embodied in carefully
drawn regulations issued by their Engineering Department.
The specifications are very exacting in every particular, entering into
_the design, material, and workmanship in minute detail_. They call
for a number of fittings and attachments not usually furnished, and a
most rigid test at the factory before shipping, and by the Inspecting
Engineers of the Insurance Companies after the pump is installed, which
secures for the purchaser the certainty of having a machine which
beyond any reasonable doubt can be relied upon to do its full duty when
emergency arises calling for its use.
There are a few quite important features not found in pumps of usual
construction. The pumps are composition fitted throughout, the water
cylinder bushings and plungers and linings to stuffing-boxes are of
composition, the piston and valve rods, made unusually heavy, are of
Tobin bronze. The mixture of the copper and tin composing the plungers
and bushings varies for the two so as to prevent their cutting. Owing
to the very high speed at which these pumps are liable to be run
during a fire, all the working parts are made excessively strong, and
the valve area and water passages are larger than usual. The interior
of each Underwriter pump is treated with a rust-proof coating, and
every precaution taken so that the pump will start instantly after an
indefinite period of disuse.
Figs. 307 and 308 exhibit two somewhat varying but acceptable forms of
the duplex steam pump.
_Among the attachments included in an outfit_ for the underwriter pump
may be mentioned: an elbow or tee for the suction connection with a
large suction air chamber, a set of brass priming pipes with special
gate and check valves for the same, an automatic water pressure relief
valve fitted to a cone and overflow pipe, a steam gauge and a special
water gauge with duplex spring, each of which in the Underwriter Pump
is mounted on an ornamental plate rigidly attached to the machine.
[Illustration: FIG. 308.]
Straightway hose valves for the proper number of streams are placed
in the neck to a very large discharge chamber, and there is also a
large discharge opening for connection to the system of hydrants and
sprinklers.
A stroke pointer is attached which travels between graduations marked
on the yoke, indicating the length of stroke which pump travels,
a one-point sight feed cylinder lubricator, a capacity plate with
enamelled face giving instructions for operating, etc., is attached to
each machine.
SPECIFICATIONS
OF THE
National Board of Fire Underwriters
FOR THE MANUFACTURE OF
STEAM FIRE PUMPS
AS RECOMMENDED BY THE
National Fire Protection Association.