Frequently Asked Questions
1)What is Thermal Expansion? - Expansion and contraction of piping systems
due to temperature changes is not unique to plastics. Changes in temperature tend
to cause a change in dimensions of any matter. But, the amount of dimensional change
for a given temperature change can vary significantly depending on the material
2)How to restrain thermal expansion?
- The restraining of the tendency of a piping system to expand/contract can result
in significant stress reactions in pipe and fittings, or between the piping and
its supporting structure. The allowing of a moderate change in length of an installed
piping system as a consequence of a temperature change is generally beneficial.
Allowing controlled expansion/contraction to take place in one part of a piping
system is an accepted means to prevent added stresses to rise to levels in other
parts of the system that could compromise the performance of, or cause damage to
the structural integrity of a piping component, or to the structure which supports
the piping. Everyone is familiar with the typical expansion loops that are periodically
placed in long pipelines subject to wide temperature changes.
3)How to prevent freezing?
-There are two very reliable methods of providing freeze protection and/or temperature
maintenance: external electrical heat tracing using “self-regulating” style electrical
heaters, and the internal method of using a smaller diameter pipe that conveys a
hot fluid to transfer heat to the fluid flowing in the annular space. Both methods
require a slightly different design method, and also require their own unique fabrication
techniques which need to be done during pipe installation. In case no care is taken
during pipe installation, but still there is chance of exposure of pipes to freezing
temperatures, it is important to fill the pipes with glycerin solution. High purity
glycerin and propylene glycol solutions are the best antifreeze liquids.
4)What is the effect of excessive use of solvent cement?
- An installation problem that we occasionally see is the use of excessive solvent
cement. The solvents in the cement themselves are readily absorbed into the wall
of the CPVC pipe and inside fitting socket resulting in solvation/softening of the
material. The solvents in the cement absorbed into the pipe wall resulting in softening
of the pipe wall to the point that the pipe wall became swollen/ softened and no
longer had sufficient strength to hold water pressure resulting in failure.
5)What is the effect of insufficient use of solvent cement?
-Sufficient solvent cement must be applied to end up with complete coverage of the
matting portion of pipe outer and fittings inner surface so that a continuous bond
is formed between the pipe and fitting surfaces. If insufficient cement is used,
voids may develop in between the pipe and fitting. The presence of the voids results
in a weakened assembly which may result in water leaking from the joint.
6)What is the life of CPVC?
-CPVC pipe and fittings, when installed underground as per the laid down procedures
had a life expectancy of more than 50 years. CPVC pipes installed decades ago are
still working satisfactorily.
7)What is the effect of external contacting material on the life of CPVC pipes &
-Care must be taken not to allow CPVC pipes to contact other materials that contain
aromatic ester plasticizers and flame retardants. Phthalate esters are highly incompatible
with CPVC pipes. Direct contact of such material with CPVC pipes results in premature
failure. Solder flux is another material that may contain chemicals that are incompatible
with CPVC. If copper pipes are being soldered in the vicinity of CPVC pipes, hot
flux can fall, spatter, or vaporize and condense on the outside surface of the CPVC
pipes causing ESC failure.Polyurethane spray foam (PUSF) insulation can be a problem.
PUSF generates heat as it cures. If the heat is trapped by a thick layer of foam
against the wall of the pipe, the heat can weaken and distort the pipe.
Also, each PUSF manufacturer has formulations that contain additives such as fire
retardants. Some of these formulations may not be compatible with CPVC. one should
consult with the PUSF manufacturer before applying PUSF in spaces where it may contact
CPVC pipes & fittings for its chemical compatibility with CPVC.
8)Can we use CPVC pipes and fittings immediately after the solar water heater storage
- YES, Jain CPVC pipes and fitting can be used immediately after the water storage
tank of solar water heater. There will not be any problem with it provided that
it is properly prevented against UV lights.
9)Can we use CPVC pipes & Fittings immediately after gas water heater?
-Use of CPVC pipes immediately after the gas water heaters is permitted with some
restriction. A care should be taken in such a way that at no point of time the flue
gases from the heater directly or indirectly come in contact with the CPVC pipe,
as the passing flue gases supply external heat to the pipe and if the flue gases
temperature is high enough, it may damage the pipe. if flue gases cannot be controlled,
in such cases avoid the use of CPVC pipe immediately after the gas water heater.
10)What extra care to be taken while installation of CPVC pipes & fittings in a construction?
Some products that are used in construction may contain chemicals that are not compatible
with CPVC pipes and fittings. Therefore care must be exercised during installation
to make sure that only chemically compatible products (e.g., metal pipe thread sealants,
fire caulks, antifreeze, antibacterial lined pipes, etc.) are used during installation.