How to Guide

102
Plastics Technical Manual
INSTALLATION PROCEDURES
Antifreeze Solutions for ABS
DWV Systems
Onlythefollowingantifreezemaybeusedwithorinconjunction
withABSDWVfoamcoresystems:
• 60%glycerol,byweight,inwater.Useundiluted.
• 22% magnesium chloride, by weight, in water. Use
undiluted.
• “Plastic Pipe Antifreeze” (especially made for plastic
pipe).
Donotuseanyothertypeantifreezeexceptthoserecommended
above.
Bedding and Backfilling
1. Even though sub-soil conditions vary widely from place
to place, the pipe backfill should be stable and provide
protection for the pipe.
2. The pipe should be surrounded with an aggregate material
which is easily worked around the sides of the pipe.
Backfilling should be performed in layers of 6 inches with
eachlayerbeingsufcientlycompactedto85%to95%
compaction.
3. A mechanical tamper is recommended for compacting sand
and gravel backfill which contain a significant proportion
of fine-grained material, such as silt and clay. If a tamper
is not available, compacting should be done by hand.
4. The trench should be completely filled. The backfill should
be placed and spread in uniform layers to prevent any
unlledspacesorvoids.Largerocks,stones,frozenclods,
orotherlargedebrisshouldberemoved.ASTMD2321
standardcallsforstonebacklltopassthroughan1-1/2”
sieveandthatrocksizeshouldbeabout1/10thofthepipe
outside diameter. Heavy tampers or rolling equipment
should only be used to consolidate only the final backfill.
Trenching
The following trenching and burial procedures should be used
to protect the piping system.
1 . Excavate the trench in accordance with applicable codes
and regulations, ensuring that the sides will be stable
under all working conditions.
2. The trench should be wide enough to provide adequate
room for the following.
A. Joiningthepipeinthetrench;
B. Snaking the pipe from side to side to compensate for
expansionandcontraction,ifrequired;and
C. Filling and compacting the side fills.
The space between the pipe and trench wall must be wider
than the compaction equipment used in the compaction
of the backll.Minimum width shall be not less than
the greater of either the pipe outside diameter plus 16
inches or the pipe outside diameter times 1.25 plus 12
inches. Trench width may be different if approved by the
design engineer.
3. Install foundation and bedding as required by the en-
gineer according to conditions in the trench bottom.
Provide firm, stable and uniform bedding for the pipe
barrel and any protruding feature of its joint. Provide a
minimum of 4 inches of bedding unless rock or unyield-
ing material is encountered in the bottom of the trench,
in which case a minimum of 6 inches of bedding shall
be used. For more severe conditions the guidelines in
ASTMD2321shouldbefollowed.Blockingshouldnot
be used to change pipe grade or to intermittently sup-
port pipe over low sections in the trench.
4. To prevent damage to the pipe and disturbance to pipe
embedment, a minimum depth of backfill above the pipe
should be maintained before allowing vehicles or heavy
construction equipment to traverse the pipe trench.
Pipe should always be installed at least below the frost
level. The minimum depth of cover should be established
Additional information is contained in ASTM D 2321
“Underground Installation of Thermoplastic pipe for
SewersandOtherGravity-FlowApplications”(non-pressure
applications)andinASTMF1668“ConstructionProcedures
for Buried Plastic Pipe.”ASTM Standards are copyrighted
documentsandcanbepurchasedfromASTMInternational:
100 Barr Harbor Drive West Conshohocken, PA 19428 or
“http://www.astm.org.”
Note:Thissectionisageneralreferenceguideandshouldnot
be considered a complete engineering resource addressing all
aspects of design and installation of pipe in buried applications.
Charlotte Pipe recommends that a design professional use
this manual along with other industry references taking into
account sub-surface conditions unique to each project and that
all installations be made in accordance with the requirements
foundinASTMD2321andincompliancewithapplicablecode
requirements.
Underground Installation
by the design engineer based upon an evaluation of spe-
cific project conditions. In the absence of an engineer-
ing evaluation, Charlotte Pipe recommends referring to
Section7.6inASTMD2321“UndergroundInstallation
of Thermoplastic pipe for Sewers and Other Gravity-
FlowApplications.”