What is PEX? PEX is cross-linked polyethylene. Through one of several
available processes, links between polyethylene macro-molecules are formed to create
essentially one large molecule of polyethylene. This
three-dimensional molecule is more resistant to temperature
extremes, chemical attack and creep deformation which makes
PEX ideal for use in hot water applications. Typical
cross-linking levels in pipe are 65%- 89%. For more than
three decades, PEX (or XLPE) has been used extensively in
Europe for hot water heating and plumbing applications.
How is PEX made? The process starts with medium to high density polyethylene
(MDPE or HDPE) resin. In some of the cross-linking methods,
chemicals are added to the base resin which, either during
extrusion or in a post-extrusion process, create the
molecular cross-links through chemical reaction. These
chemical methods can be compared to the vulcanization of
rubber. Another method, radiation (nuclear or electron
beam), uses high energy irradiation of the extruded pipe to
form the molecular links. Finished properties of
cross-linked material from these commercial methods are very
similar.
What cross-linking method is used to
make Vanex PEX? Vanguard uses the silane method of chemical cross-linking.
This process uses HDPE resin with additives that react when
the extruded pipe is exposed to heat and moisture. The
chemical reaction stops when cross-linking reaches 70-80%.
Even with further exposure, no additional reaction will take
place. Vanex PEX is tested to check the degree of cross-link
before it leaves the factory.
What about the chemicals used in
cross-linking Vanex? Are they harmful? All of the chemical additives used in making Vanex are
depleted during the cross-linking process. NSF International
(formerly the National Sanitation Foundation) has tested
Vanex tubing to Standard 61 (Health Effects) and found it
safe for use in potable water systems.
What sizes is Vanex available in? Vanguards Vanex PEX tubing is made in 3/8", 1/2", 5/8”, 3/4"
and 1" sizes. The tubing is copper tube size, meaning that
the actual outside diameter of the PEX is the same nominal
size of copper tubing. Vanex has a wall thickness
corresponding to SDR9 (Standard Dimension Ratio 9) meaning
that the wall thickness is 1/9th of the outside diameter and
is proportionate for each size maintaining the same pressure
ratings for all sizes.
What about freeze-break resistance? Vanex PEX will stretch slightly to accommodate the expansion
of frozen water, then return to its original size when the
water thaws. This memory is a feature of cross-linked
material, giving it thermo-elastic behavior. Although
freeze-break resistant, no pipe is freeze-break proof under
all circumstances. Insulation of plumbing pipes as required
by local codes is still recommended.
What about flexibility and fewer
fittings for changes in direction? Vanex is flexible and requires fewer fittings to install
since most changes in direction can be accomplished without
the need for elbows. Vanex is simply curved around
obstructions unlike rigid piping materials. Compared to
branch and main plumbing systems with rigid piping, a Vanex
PEX system uses only about 1/2 of the fittings.
What about the use temperatures and
pressures ratings? Vanex PEX is rated for 100 psi @ 180° F and 160 psi @ 73° F.
Vanex PEX tubing is manufactured, sampled, tested, marked
and third-party-listed in accordance with ASTM standards
F876 and F877, and CSA (Canadian Standards Association)
standard B137.5.
What approvals does Vanex PEX have? Vanex PEX was the first of a very limited number of PEX
tubing manufacturers to acquire a third party certification
listing with NSF, International for both chlorinated hot and
cold potable water plumbing systems and chlorinated
recirculating hot water plumbing loops. Vanex PEX is also
third party listed for potable water plumbing use by: NSF
International, IAPMO (International Association of Plumbing
and Mechanical Officials), ICBO (International Conference of
Building Officials) Evaluation Service and Warnock Hersey.
Also, the PEX material used in the manufacture of Vanex is
listed by the PPI (Plastics Pipe Institute).
What about code approvals? Is PEX
referenced in the plumbing codes? Yes. Currently, PEX manufactured to ASTM F876/F877 is listed
in the BOCA National Plumbing Code, the BOCA National
Mechanical Code, the Standard Plumbing Code (SBCCI), the
CABO One and Two Family Dwelling Code and the International
Plumbing Code (IPC) for use in plumbing systems as well as
many state and local codes. Before installing Vanex PEX,
check with your plumbing official for state or local
variances from these national codes. Contact Vanguard for an
up to date list of approvals.
How can I be assured that Vanex PEX
will hold up? Vanex PEX meets or exceeds all of the industry standards
established to ensure quality and reliability. Through
independent laboratory testing of tens-of-hundreds of pipe
samples, test data is developed and analyzed to determine
that Vanex PEX will perform. Continual monitoring by
Vanguard and several third-party test agencies assures
consistently high-quality.
What do the letters A, B and C mean
when used to describe PEX? The ABC letter designation system is used in Europe to
identify the process by which a particular PEX tubing is
cross-linked. It is NOT a grading system, but simply an
identification system. PE-Xa is cross-linked with the
peroxide method, PE-Xb is cross-linked with the silane
method (Vanex is silane method) and PE-Xc is cross-linked by
electron beam irradiation.
What about the CRIMPSERT® fittings
systems? The CRIMPSERT fitting system is extremely installation
efficient and reliable. The system has a 25 year history of
performance in flexible plumbing systems. The system is
simple to assemble and requires no glues, solders, torches
or lubricants.
To make a CRIMPSERT connection, simply: 1) Position the crimp ring and insert the fitting into the
tubing 2) Crimp the ring in place with the correct size crimp tool Each size takes its own, specially sized crimp tool to
ensure consistent, properly made connections. CRIMPSERT is a
gaugeable system allowing checking of the crimp connections
for proper crimp size.
All CRIMPSERT components and tools meet or exceed the
requirements of ASTM standard specification F1807. This
assures a consistent fit and compatibility with components
from other manufacturers also making fittings to F1807.
Can I use Vanex PEX with the MANABLOC®
system? Yes, Vanex is ideal for MANABLOC installations. The
flexibility of PEX allows one continuous length of tubing
from the MANABLOC directly to each fixture.
Can I use Vanex PEX in Hydronic
Heating Systems? Yes, Vanex PEX is perfectly suited for hydronic heating
loops. An oxygen-barrier version of the tubing and a
complete line of heating system components are also
available.
|