The Water Supply of the El Paso and Southwestern Railway from Carrizozo to Santa Rosa, N. Mex. | Page 3

with as much hot asphalt as it
will carry.
Steel Bands.--The specifications required bands of mild steel, of 60,000
lb. strength, with an elastic limit half as great. The winding was spaced
to limit the tension to 15,000 lb. per sq. in. If severe water-hammer is
present, the ordinary working stress should be materially less than the
latter, otherwise the spiral bands will stretch enough to permit the water
to spurt out between the staves. This was determined to be true on
4,500 ft. of 12-in. pipe connecting the Carrizozo Reservoir with a water
column at the roundhouse there. In pumping tests at the mills, attempts
were made, at various times, to burst the pipe, but they never succeeded.
Before the elastic limit was exceeded, the water was running out
between the staves as fast as the pump forced it in. On the following
day, pipe thus tested would carry the pressure for which it was designed
without leaking. Except for defects in the band, pipe of this kind will
not burst in the service for which it is properly designed. This is true,
without exception, of the 100,000 pieces of pipe in this service.
There has been some trouble with a number of the riveted splices on the
banding. Such a splice occurs for every spool of banding used. In every
case where one of these splices has pulled apart, the break was the
result of defective riveting, permitting the rivets to pull out. In no case

has a rivet been found sheared off, and even one good rivet appears to
be sufficient to prevent rupture. The explanation is found in the high
frictional resistance between the band and the pipe, which distributes
the weakness of a bad splice over several adjacent turns of the band
around the pipe. The band loosens a few turns only on either side of a
parted splice, generally not more than three. In no case has any pipe
been removed from the trench, repairs being made without interruption
to the flow of water.
It is desirable to substitute welding for the riveting of these splices. The
trouble is not present with the round band, the wrapped splice of the
latter giving practically 100% efficiency.
The flat band was chosen for this work because it is the more
effectively buried in and protected by the asphalt, and will not crush the
soft wood staves under high pressure. The longevity of either the flat or
the round steel band is dependent primarily on effective protection
against contact with corrosive elements. Wrought iron should be used
for this kind of service, and, for the same reason, for many other
purposes. Engineers and consumers should join in some comprehensive
and effective plan to bring back the old-time production of high-grade
wrought iron.
Wood Staves.--The staves of this pipe are of Michigan and Canadian
white pine. This pine cannot now be had of clear stuff or in long
lengths in large quantities; otherwise, it is unexcelled. Douglas fir and
yellow pine, coarser and harder woods, have the advantages of clear
lumber and long length. Cypress is not as plentiful, and redwood is
costly. The mill tests did not determine definitely the minimum degree
of seasoning necessary, and press of time compelled the acceptance of
some rather green lumber. Service tests do not show that there is any
abnormal leakage from pipe made of such lumber, and it could not now
be distinguished in the trench by such tests. Undoubtedly, however,
thorough air seasoning should be required.
Bored Pipe.--Owing to its small size, a part of the 3-1/2-in. pipe was
bored from the log. This was a mistake, for bored pipe has a rough
interior and a reduced capacity. The inspection and culling are difficult

and unsatisfactory, and imperfections readily apparent in a stave
frequently escape detection in bored pipe.
Pipe Joints.--The chamber and tenon of this pipe is an all-wood joint, 4
in. deep. An iron sleeve makes a better and stronger joint. It
compensates for any lack of initial tension in the banding over the
chamber of the wood joint, and secures full advantage of the swelling
of the wood. Cast iron is better than steel; it is more rigid, and its
granulated surface breaks up the smoothness of the wood surface
swelling against it. One objection to the cast-iron sleeve is that of cost,
but it adds 4 in. to the effective length of every section of pipe, as
compared with the wood joints. On the Pacific Coast, a banded
wood-stave sleeve is used with success.
Coating.--To preserve the banding from corrosion and the wood from
exterior decay, the pipe is thoroughly enveloped in refined asphalt
having a flow-point adjusted to the prevailing temperature during
shipment and laying. One grade can be used through a considerable
range of