E.

TIE-INS AND FITTINGS .

Since the 0.0. of P.V.C. pipe is the same as D.|. pipe, the
cast iron fittings and couplings now used with D.I. pipe
are compatible for use with P.V.C. pipe.

For .the Purpose of tie-ins to existing mains and setting of
tees, valves, eatec., in mainiine construction, P.V.C. pipe
may be cut with a hand or ski type saw. The cut end of
the pipe must be bevelled with a coarse file or rasp prior
to assembiy,. Unlike Del. pipes, harness clamps cannot be
used on P.V.C. pipes for the purpose of restraining
thrusts. Thrust blocks must be used without exception.

TRENCH WIOTH, BEDDING AND BACKFILL

As with amy underground conduit, the Engineer designing the
pipe system must take into consideration amongst other

‘things, the expected total toad on the conduit, the ground

conditions and the design strength of the pipe. Since
P.V.C. AWWA C900 pipe is a flexible conduit, the Engineer
must follow the established procedures for designing the
instailation of flexible conduits. The construction crew
must aiso recognize the fundamental! differences between the
installation of flexible and rigid conduits and adhere to
The specified trench width, bedding and backfil|
requirements.

DENSITY OF MATERIAL

‘P.V.C. pipe is approximately five times lighter than v.I.

pipe. The lower density of P.V.C. pipe is an advantage
since this would result In a lower handting cost. On the
other hand, the lower density may cause the bipe to float
while the soil surrounding the pipe is being heavily
compacted or when the trench bottom is ¢illed with water.
Additional precautions for anchoring the P.V.C. pipe may be
nacessary under these conditions.

The Uni-Bell Piastic Pipe Association's "Handbook of P.V.C.
Pipe", and Manville'ts "Biue Brute Instatlation Guide", give
in considerable detail! the recommended construction and
handling practice of P.V.C. pipe. For the most part the
manual covers good construction practices which ara
applicable to any underground conduit installation as we | |
as special considerations for P.V.C. pipe. The most
important factor In handling and installing the P.V.C. pipe
Successfully as with any other meterial, is knowing its
properties and how it will react under varying conditions,