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VENT PIPE PREPARATION
1. INITIAL PREPARATION
A.
Make sure the solvent
cement you are planning
to use is
designed for the specific application you are attempting.
B.
Knowthe physical and chemical characteristics
and limitations
of the PVC and CPVC piping materials that you are about to
use.
C.
Know the reputation of your manufacturer
and their products.
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 inches
(15.2 cm) 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.
APPLICATORS
Fire Hazard
• Primers and cements are extremelyflammable,and
must not be stored or used near heat or open flame.
• Also, use only in a well ventilated area.
Select a suitable pure bristle type paint brush. Use a proper width brush
or roller to apply the primer and cement (see chart below).
Speedy
application
of cement is important due to its fast drying characteristics.
IMPORTANT
NOTE: A dauber type applicator should only be used on
pipe sizes 2" and below. For larger diameter pipe, a brush or roller must
be used.
RECOMMENDED
BRUSH*
SIZE
FOR PRIMER
AND CEMENT
APPLICATIONS
Nominal Pipe
Size Brush Width
IIPS_
IINS._
2
1-1 !2
3
1-1/2 - 2-1/2
*USE ONLY NATURAL BRISTLE
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
21
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