The boom in the building and construction industry, especially in the housing
and commercial building sector has fueled
high demand for cost effective, reliable,
quality piping and plumbing systems. The choice
of piping systems for water utilities is based
on overall long term value. They must deliver
on factors like long term costs, reliability,
versatility, environmental effect, drinking
water safety and public health. CPVC Piping
systems are the ideal choice, because they
are corrosion resistant, durable, smooth,
friction free, resistant to bacterial growth
and environment friendly, besides a host of
other user friendly features.
CPVC Pipes - Manifold Benefits
CPVC Pipes provides several critical advantages
· Aesthetic, extremely easy, cost
effective to handle and install
CPVC pipes are lightweight, which means low
shipping costs along with faster, safer and
easier handling, cutting and installation,
reducing overall labour costs. Installation
is easy by fast cold welding, which is cost
effective as no electric/heat source is required.
Simple cutter, chamfering tool and CPVC solvent
are the only requirements for 100% leak proof
· Excellent resistance to chemicals,
corrosion and abrasion
Does not breakdown ever under harshest water
conditions and aggressive service conditions
like low pH water, coastal salt air exposure
and corrosive soils. It can even be buried
directly under concrete slabs with no chemical
interaction with concrete.
· Most suitable for carrying drinking
Retards bacterial growth, which keeps the
water quality healthy and very good. They
are suitable even for aggressive water pH
levels of less than 6.5. CPVC Pipes meant
for carrying water should have NSF certification
according to ANSI/NSF Standard 61/ program
policy 45 (RVCM levels in these pipes are
so low as to be undetectable).
· Smooth Internal Surface
Absence of scaling, pitting and leaching leads
to smooth and full bore flow and low water
noise. It maintains full water carrying capacity
because of no scale buildup, avoiding water
· Energy efficient, lower thermal
conductivity and insulation cost
It is self insulating with lower thermal conductivity,
which greatly reduces heat and therefore requires
low insulation levels and cost.
· Excellent performance in tough
These piping systems are tough, rigid and
strong with higher pressure bearing capacity.
It requires less hangers and supports with
· High flexibility virtually eliminates
No water hammer arrestors required under normal
conditions as intensity of water hammer is
approximately one third that of copper or
· Extremely fire resistant
It has integral flame retarding property with
very high Limiting Oxygen Index (LOI) of 60.Thus
in air these pipes cannot be the ignition
source of fire or support or sustain combustion.
It does not increase fire load, has low smoke
generation and low flame spread without flaming
· Completely leak proof
The cold welding using CPVC solvent is fast
and simple, ensuring leak free installation
for the entire life span of the piping system.
· Cost - effective, durable with
excellent long term reliability
CPVC pipes have high impact strength and durability.
It has low initial cost and lower maintenance
costs as against competitive materials.
· Ideal for home plumbing systems
The CPVC system is four times quieter than
copper plumbing systems, reducing not only
the sound of running water, but also the pounding
noise of the water hammer. Its thermoplastic
properties provide excellent insulation to
virtually eliminate sweating and condensation.
It keeps hot water hotter and cold water colder
than copper plumbing. There is minimal energy
loss through pipe walls, saving money on heating
· Less subject to job site thefts as
compared to copper or metal pipes.
· Relative price stability over a long
· Eco friendly as its production is
very energy efficient.
Wide Range of Applications
The excellent qualities of CPVC Pipes make
them ideal for
· Hot and cold water distribution in
residential, industrial and public projects.
· Carrying drinking water and food
· Water and waste water treatment systems
· Transportation of chemical and hot
corrosive fluids, which includes a wide variety
of inorganic acids, bases used in chemical
· Use in industries like metal finishing,
plating and treatment, pulp and paper, air
pollution control, mining, aerospace, textile,
food and beverage processing, fine sprinkler
piping and municipal projects.
· Use as high tension cable protection
pipe for electric net improvement (Large dia.
· Solar heating, central heating and
radiant floor heating application
Installation and Maintenance of CPVC Pipes
CPVC Pipes and Fittings for potable water
applications are available in CTS (Copper
Tube Size) ½ through 2 inches and in
IPS (Iron Pipe Size) ¼ through 12 inches.
CPVC Pipes and Fittings are joined by solvent
cementing and CPVC Pipe and other piping materials
are connected by use of adapter fittings.
These CPVC Pipes are available in wall thickness
of either SDR 11(Copper Tube Size), SDR -
PR, Schedule 40 or Schedule 80. These pipes
and fittings are pressure rated as per ASTM
D 2846 for continuous use at 100 psi at 180
degrees F and 400 psi at 73.4 degrees F.
These pipes should be designed with a water
flow rate between 5 and 12 feet/sec and while
laying them it must be remembered that CPVC
Pipes expand and contract more than metallic
pipes. Compensation must be provided for expansion
and contraction, where they are installed
in long, straight lengths, by using offset
piping arrangements like loops or bends. Adequate
horizontal supports and vertical hangers at
appropriate distances must be provided.
For cutting CPVC Pipes fine tooth saws/simple
hack-saws/rachet saws or a circular tubing
cutter modified with a plastic cutting blade
can be used. Care should be taken to avoid
cracking of the pipe wall while cutting. For
larger diameter pipes power tools are also
used at major sites for cutting.
Only CPVC solvent cements which meet the specifications
of ASTM F 493 should be used while installing
CPVC Pipes. Orange CPVC solvent cement or
Purple primers are used when required to facilitate
identification and plumbing inspection. Unpigmented
CPVC solvent cement/primer, clear cement/primer,
one step cements are the other alternatives
available for joining purposes.
Teflon Tape can be used with CPVC threaded
adapters very effectively. However before
using paste or pipe dope, it is better to
check with the manufacturer as some of these
pastes or dopes may contain solvents incompatible
While connecting CPVC Pipes to gas water heaters,
the pipe should not be located within 6"
of the heater's flue, to avoid the possibility
of damage to the plastic pipes from the flue
heat. A flexible appliance connector or metal
nipple is used for the connecting. However
the hot water from the heater does not affect
CPVC is affected by prolonged exposure to
sunlight/ultraviolet radiation. Pigments are
added to CPVC to make pipe and fitting resistant
to degradation. CPVC pipes can be protected
from sunlight /UV radiation by painting them
by exterior grade latex paint.
If a section of the piping systems freezes
in the cold, it can be thawed by wrapping
it with a cloth saturated with hot water and
keeping the cloth hot by re-dipping in hot
water till required. Alternatively a low wattage
heater/blower can used to blow heated air
on the frozen area to thaw the pipe.
Important CPVC related Standards
Water Supply This is a critical certification
without which CPVC Pipes cannot be used
for carrying potable water
||CPVC Hot Cold Water Distribution
||CPVC Schedule 80 CPVC Fittings
||CPVC Schedule 40 & 80
||CPVC Pipes Dimension
||CPVC Pipes General Quality
Requirements and Testing
||CPVC Pipes and Fittings
for Hot and Cold Water Distribution
||CPVC Pipes and Fittings
for Hot and Cold Water Distribution
||Plastics Piping Systems
for Hot and Cold Water Installations -Chlorinated
Poly Vinyl Chloride (PVC - C)
CPVC Pipe Extrusion
CPVC Pipe processing is done on Twin Screw
Pipe Extrusion Plants, where the specially
designed screws are triple chrome plated for
longer life. Each screw requires special screw
geometry to process for optimum shear, as
the material is much more heat sensitive as
compared to normal PVC. The screws are designed
to give good melt homogeneity. The Die Head
manufactured from stainless steel offers least
resistance and stagnancy to flow path. The
flow optimized Spider Die offers uniform melt
distribution and very good flow properties
throughout the entire flow channel. It also
allows optimum dwell time spectrum with targeted
temperature guidance of sensitive material
to give outstanding pipe quality. It also
ensures benefits like low pressure built-up,
low melt temperature, even with high throughput.
CPVC being highly viscous requires high torque
gear box and drive.
Next Generation CPVC Pipe Extrusion Plants
Next Generation CPVC Twin Screw Extrusion
Plants are being manufactured for the first
time in India, incorporating all critical
aspects mentioned above. This plant with Extruder
having L/D ratio of 22, has successfully produced
CPVC Pipes of excellent quality. Earlier all
CPVC Pipe Plants were imported. Downstream
Equipments like stainless steel Vacuum Calibrator,
Spray Baths for intensive cooling, Haul-off
Unit, Cut-off Unit etc., are part of the Line.
These plants are capable of manufacturing
CPVC pipes which conform to NSF - USA and
other stringent International quality standards
likes DVGW (Germany), WRAS (U.K.), CSTV (France),
KIWA (Netherlands), TSE (Turkey), CSA (Canada)
CPVC Pipes - Increasing Demand
These pipes have been successfully used worldwide
for over forty years. It has a proven track
record of being used in water distribution
applications in houses, apartments, hotels,
condominiums and commercial establishments
with increasingly developing demand.
Author : Mr. T. K. Chattopadhyay, VP (Works),
Kabra Extrusiontechnik Ltd.