Pex Piping:
Pex (Cross-linked Polyethylene) piping is the
new material used for plumbing. Polyethylene is an extremely effective
alternative to pipes made from traditional materials such as cast iron, steel,
concrete, etc for technical and economic reasons. The big development and
widespread use of polyethylene pipes is due to the its special properties. Below
is a brief description of these especial properties.
Abrasion.
Polyethylene's resistance to abrasion is greater than that of steel and
concrete. This makes it ideal for conveying solid particles suspended in water
(sludge) and for sand and gravel dredging operations. When the piping is laid,
the outer surface should not, however, be scratched or cut by sharp objects. The
pipes should therefore be handled with care in order to prevent deep cuts to the
surface that would reduce the piping mechanical performance.
Flexibility
Polyethylene's high flexibility and its ability to regain its original shape
after deformation make it readily absorb vibrations, collisions and stress due
to ground movement. As a result it is suitable for installation in unstable
areas Lightness
Polyethylene pipes have a low specific weight and can therefore be easily
transported and installed. This results in considerable costs savings.
Corrosion
Polyethylene is chemically inert within its normal temperature range of use. For
this reason, it does not crack or corrode and the wall thickness is not reduced
after electrochemical reactions with the surrounding terrain. It does not
encourage the growth of algae, bacteria and fungi.
Low temperatures
Polyethylene's mechanical properties allow the pipes to work at low temperatures
such as –60°C. Chemical
effects
Polyethylene has good resistance to a wide range of chemicals. Nevertheless, if
it comes into contact with certain highly oxidizing chemical agents over a long
period of time, it can deteriorate. Detergents may encourage fractures to
develop, especially at high temperatures. Some solvents (hydrocarbons such
petroleum and oil) may be absorbed, this reducing mechanical resistance and
affecting the taste of the transported fluid. Heat stability
Exposing polyethylene to normal environmental temperature variations does not
make it deteriorate. When pipes are manufactured, the material is subjected to
temperatures of 200°C - 240°C, so certain stabilizers are added to prevent
chemical and physical deterioration.
Resistant to UV rays
To prevent polyethylene from deteriorating (ageing) through exposure to
ultraviolet light (sunlight), carbon black is added to it. This stabilizer enables the pipes to be stored outdoors for a long time.
Poor conductor of heat and electricity
Polyethylene is a poor conductor of heat but is flammable. Direct flame must not
therefore be used to defrost pipes or for other operations. Pipes should also be
protected if they are near sources of heat that could raise its surface
temperature above 60°C. Polyethylene is also a poor conductor of electricity,
so that no particular precautions need to be taken in laying the pipes.
Non-toxic
Polyethylene is a completely non-toxic material and is therefore suitable for
conveying drinking water or water that is to be made potable.
Many
municipalities require certification for installation of PEX. Doran
is certified for installation of PEX.
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