Warranty Guide

57
Horizontal and Vertical
Support Spacing For ABS,
PVC and CPVC Pipe
Adequate support for any piping system is a matter of great
importance. In practice, support spacings are a function of
pipe size, operating temperatures, the location of heavy valves
or fittings, and the mechanical properties of the pipe material.
Most plumbing codes and building codes require support for
horizontal pipe lines every 3 feet for pipe in 1/2”-1” diameters,
and every 4 feet for pipe with diameters greater than 1”.
Support spacing should be in accordance with applicable
plumbing and building codes.
To ensure the satisfactory operation of a DWV or pressure
piping system, the location and type of hangers should be
carefully considered. The principles of design for metallic
piping systems are generally also applicable to DWV or
pressure piping systems, but with some notable areas where
special consideration should be exercised. Hangers should not
compress, distort, cut or abrade the piping.
All piping should be supported with an approved hanger at
intervals sufficiently close to maintain correct pipe alignment
and to prevent sagging or grade reversal. Pipe should also be
supported at all branch ends and at all changes of direction.
Support trap arms as close as possible to the trap. In keeping
with good plumbing practices, support and brace all closet
bends and fasten closet flanges.
(1) Concentrated loads (ie: Valves and other appurtenances)
should be supported directly so as to eliminate high stress
con centrations. Should this be impractical, then the pipe
must be supported immediately adjacent to the load.
(2) In systems where large fluctuations in temperature occur,
allowances must be made for expansion and contraction
of the piping system. Since changes in direction in the
system are usually sufficient to allow for expansion and
contraction, hangers must be placed so as not to restrict
this movement.
(3) Since plastic pipe expands or contracts approximately
five times more than steel, hangers should not restrict this
movement. When using a clamp-type hanger, the hanger
should not force the pipe and fittings into position.
(4) Hangers should provide as much bearing surface as
possible. To prevent damage to the pipe, file smooth any
sharp edges or burrs on the hangers or supports.
(5) The use of coated hangers with plastic pipe is neither
recommended or necessary. If coated hangers are used,
verify that the rubber or vinyl coating utilized does not
contain plasticizers and is chemically compatible with the
plastic pipe material.
(6) Plastic piping systems must not be placed alongside
steam or other high temperature pipe lines or other high
temperature objects.
(7) Support spacing for horizontal piping systems must be
determined by the maximum operating temperature the
system will encounter. The piping should be supported
on uniform centers with supports that do not restrict the
axial movement.
(8) For vertical lines, it is recommended that an engineer
design the vertical supports according to the vertical
load involved. Vertical CPVC piping should be properly
supported and have a mid-story guide, unless thermal
expansion requires another design.
(9) Changes in direction should be supported as close as
practical to the fitting to avoid introducing excessive
torsional stresses into the system. Please see the
associated chart showing the recommended support
spacing according to size, schedule, and operating
temperatures. These spacings apply to continuous spans
of uninsulated lines, with no concentrated loads, conveying
liquids with specific gravities of up to 1.00.
Special Considerations for
CPVC Pipe
The pipe should not be anchored tightly by the support, but
secured in a manner to allow for movement caused by thermal
expansion and contraction. It is recommended that you use
clamps or straps that allow pipe to remain away from the
framing, thus reducing the noise generated when pipe is
allowed to rub against wood. Use hangers and clamps that
are chemically compatible with CPVC.
DESIGN & ENGINEERING DATA
Pipe or fittings may be damaged by contact with
products containing incompatible chemicals resulting in
personal injury or property damage.
• Verify that paints, thread sealants, lubricants, plasticized
PVC products, foam insulations, caulks, leak detectors,
insecticides, termiticides, antifreeze solutions, pipe
sleeve, firestop materials or other materials are
chemically compatible with CPVC.
• Do not use edible oils such as Crisco
®
for lubricant.
Plastic insulators do not need to be used when CPVC pipe
passes through wood studs. However, when CPVC pipe passes
through metal studs, some forms of protection must be used
to isolate the pipe from abrasion and to prevent noise.
NOTICE: The above information on this page provides general
guidelines. It should be used only as a reference and not as a
guarantee of performance. Specific installation instructions
and techniques may be required as a result of local plumbing
and building codes, engineering specifications and instructions.
Failure to compensate for expansion and contraction
caused by temperature change may result in system
failure and property damage.
• Do not restrict expansion or contraction. Restraining
movement in piping systems is not recommended and
may result in joint or fitting failure.
• Use straps or clamps that allow for piping system
movement.
• Align all piping system components properly without
strain. Do not bend or pull pipe into position after being
solvent welded.
• Do not terminate a pipe run against a stationary object
(example: wall or floor joist).
• Do not install fittings under stress.