Installation Guide

102
Plastics Technical Manual
INSTALLATION PROCEDURES
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 backfill 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.
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.
Unstable Soil
Burial of pipe under slab in soils that are unstable is
often accomplished by suspending the piping systems from
structural slabs. The use of plastic pipe in such installations
mustbeinaccordancewithASTMF2536.Cellularcorepipe
is specifically not permitted for these applications.
CTS CPVC Under-Slab
Installations
FlowGuard Gold
®
andReUze
®
CPVC is suitable for under-
slab installations when approved by prevailing plumbing and
building codes.
When performing under-slab installations, it is important
that the pipe be evenly supported. Charlotte Pipe recommends
pressure testing with water prior to backfilling and pouring
the slab. Backfill should be clean earth, sand, gravel or other
approved material, which must not contain stones, boulders
or other materials that may damage or break the piping. The
pipe should be protected from damage by tools and equipment
used to finish the concrete. Because CPVC does not react to
concrete or stucco and is inert to acidic soil conditions, it does
not need to be sleeved. NOTE: Some code jurisdictions require
sleeving at slab penetrations. Verify code requirements prior
to installation.
Do not bend FlowGuard Gold
®
andReUze
®
1/2”and3/4”pipe
inaradiustighterthan18”;1”pipeshouldnotbebentina
radiustighterthan24”.
Check applicable plumbing and building codes before making
under-slab installations.
In-Slab Installations
CPVC is not suitable for in-slab radiant heating systems.
CPVC piping can be installed embedded in a concrete slab,
because CPVC does not react to concrete or stucco and it is
inert to acidic soil conditions.
ABS and PVC Under-Slab
Installations
Although PVC or ABS is unaffected by direct contact with
or burial in concrete, care must be taken to properly support
any piping system when pouring concrete so that the weight of
the concrete does not affect the pipe system and that any heat
generated by curing concrete does not exceed the capability
of the system.
Some codes require sleeving or protection of piping at slab
penetrations.Whilenotnecessaryduetoanycorrosionissues,
always follow applicable code requirements on any installation.