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D.
Know your own qualifications or those of your contractor.
The solvent welding technique of joining PVC and
CPVC pipe is a specialized skill just as any other pipe
fitting technique.
E.
Closely supervise the installation and inspect the
finished job before start-up.
F.
Contact the manufacturer, supplier, or competent
consulting agency if you have any questions about the
application or installation of PVC and CPVC pipe.
G.
Take the time and effort to do a professional job.
Shortcuts will only cause you problems and delays in
start-up. By far, the majority of failures in PVC and CPVC
systems are the result of shortcuts and/or improper
joining techniques.
2. SELECTION OF MATERIALS
• Cutting Device - Saw or Pipe Cutter
• Deburring Tool, Knife, File, or Beveling Machine (2" and
above)
• Brush - Pure Bristle
• Rag - Cotton (Not Synthetic)
• Primer and Cleaner
• Solvent Cement - PVC for PVC Components and CPVC
for CPVC Components
• Containers - Metal or Glass to hold Primer and Cement.
Select the type of PVC or CPVC materials to be used on
the basis of their application with respect to chemical
resistance, pressure rating, temperature characteristics,
etc.
• Insertion Tool - Helpful for larger diameter pipe and fittings
(6" and above).
PRIMER
It is recommended that Tetrahydrofuran (THF) be used to prepare
the surfaces of pipe and fittings for solvent welding. Do not use
water, rags, gasoline or any other substitutes for cleaning PVC
or CPVC Surfaces. A chemical cleaner such as MEK may be
used.
CEMENT
The cement should be a bodied cement of approximately 500 to
1600 centipoise viscosity containing 10-20% (by weight) virgin
PVC material solvated with tetrahydrofuran (THF). Small
quantities of dimethyl formamide (DMF) may be included to act
as a retarding agent to extend curing time. Select the proper
cement; Schedule 40 cement should be used for Schedule 40
pipe. Never use all-purpose cements, commercial glues and
adhesives or ABS cement to join PVC or CPVC pipe and fittings.
SAFETY PRECAUTION: PRIMERS AND CEMENTS ARE
EXTREMELY FLAMMABLE, AND MUST NOT BE STORED OR
USED NEAR HEAT OR OPEN FLAME. ALSO, USE ONLY IN A
WELL-VENTILATED AREA.
3. MAKING THE JOINT
A. Cutting
Pipe must be squarely cut to allow for the proper interfacing
of the pipe end and the fitting socket bottom. This can be
accomplished with a miter box saw or wheel type cutter. Wheel
type cutters are not generally recommended for larger
diameters since they tend to flare the corner of the pipe end.
If this type of cutter is used, the flare on the end must be
completely removed.
NOTE: Power saws should be specifically designed to cut
plastic pipe.
STEP A
B. Deburring
Use a knife, plastic pipe deburring tool, or file to remove
burrs from the end of small diameter pipe. Be sure to
remove all burrs from around the inside as well as the
outside of the pipe. A slight chamfer (bevel) of about 10°-
15° should be added to the end to permit easier insertion
of the pipe into the end of the fitting. Failure to chamfer
the edge of the pipe may remove cement from the fitting
socket, causing the joint to leak.
STEP B
C. Test dry fit of the joint
Tapered fitting sockets are designed so that an
interference fit should occur when the pipe is inserted
about 1/3 to 2/3 of the way into the socket. Occasionally,
when pipe fitting dimensions are at the tolerance
extremes, it will be possible to fully insert dry pipe to the
bottom of the fitting socket. When this happens, a sufficient
quantity of cement must be applied to the joint to fill the
gap between the pipe and fitting. The gap must be filled
to obtain a strong, leak-free joint.
D. Inspection, cleaning, priming
Visually inspect the inside of the pipe and fitting sockets
and remove all dirt, grease or moisture with a clean dry
rag. If wiping fails to clean the surfaces, a chemical
cleaner must be used. Check for possible damage such
as splits or cracks and replace if necessary.
Depth-of-entry mark
Marking the depth of entry is a way to check if the pipe has
reached the bottom of the fitting socket in step F. Measure
the fitting depth and mark this distance on the pipe O.D.
You may want to add several inches to the distance and
make a second mark as the primer and cement will most
likely destroy your first one.
