FREQUENTLY ASKED QUESTION
What is PEX?
What are
recommended uses for PEX?
Can PEX be
used under the slab?
Will PEX
systems help save on utility bills?
What joining
systems are available?
How long can
PEX be exposed to sunlight?
What are
temperature limitations for PEX?
How are PEX
systems tested for leaks?
How soon
after installation can you pressure test a PEX
tubing installation?
Is PEX
freeze-break resistant?
How do I thaw
PEX lines?
Can PEX be
joined with solvent cement?
How long has PEX been used?
What is PEX?
PEX is
cross-linked Polyethylene. Through one of
several processes, links between polyethylene
macromolecules are formed to create bridges
between PE molecules (thus the term
"cross-linked). This resulting molecule is more
durable under temperature extremes, chemical
attack, and resists creep deformation, making
PEX an excellent material for hot water
applications (up to 200° F).
Back to top
How long has
PEX been used?
PEX was
developed in the 1960s. PEX tubing has been in
use in many European countries for plumbing,
radiant heating and snow melt applications since
that time. PEX was introduced in the United
States in the 1980s, and has seen significant
growth in market demand and production.
Back
to top
What are
recommended uses for PEX?
PEX 's
flexibility and strength at temperatures ranging
from below freezing up to 200 degrees Fahrenheit
makes it an ideal piping material for hot and
cold water plumbing systems, hydronic radiant
heating systems, snow melting applications, and,
even ice rinks and refrigeration warehouses.
Back
to top
Can PEX be
used under the slab?
Yes. The
flexibility of PEX allows it to be supplied in
coils meaning installations under the slab can
be made with a single, continuous length without
the need for fittings under the slab. PEX is not
affected by concrete, or chemicals in concrete
(it is commonly encased in concrete for radiant
floor heating). PEX, however, must be sleeved
when penetrating a concrete slab.
Back
to top
Will PEX
systems help save on utility bills?
Yes. Home run or
manifold plumbing systems utilizing PEX tubing
can substantially reduce water and energy
consumption in a home. The home-run concept
provides dedicated direct lines from the
manifold to the fixtures, reducing the amount of
water that must be purged from the lines to get
hot water at the fixture. Direct lines can be
sized to the fixture requirements, further
reducing the amount of time to wait for hot
water. Faster hot water delivery reduces water
waste and the amount of times the water heater
must cycle to supply hot water.
Back
to top
What joining
systems are available?
There are
several methods of connecting PEX, all of which
involve mechanical fittings. There are two
approved standard specifications for PEX
connections: ASTM F 1807 and ASTM F 1960. Both
reference mechanical insert fittings. The crimp
fittings specified in ASTM F1807 are the most
widely used. Other fitting systems, including
insert and outside diameter compression
fittings, are also available. PEX cannot be
joined by solvent cement or heat fusion methods.
Back
to top
How long can
PEX be exposed to sunlight?
PEX tubing is
not intended for outdoor applications and must
be stored in a covered environment not exposed
to direct sunlight. Maximum UV exposure is no
more than 60 days.
Back
to top
What are
temperature limitations for PEX?
PEX tubing can
be used up to 200° Fahrenheit for heating
applications. For plumbing, PEX is limited to
180° F. Temperature limitations are always noted
on the print line of the PEX tubing. Recommended
140 max for safety and conservation
Back
to top
How are PEX
systems tested for leaks?
PEX plumbing and
radiant heating systems can be pressure tested
using either water or air to check for leaks.
Follow manufacturer's instructions.
Back
to top
How soon
after installation can you pressure test a PEX
tubing installation?
PEX
systems can generally be tested immediately
after the installation is complete. There is no
wait time for glue to dry or joint to cool off.
Weather should be considered and manufacturer's
instructions followed in cold weather.
Back
to top
Is PEX
freeze-break resistant?
PEX piping is
freeze damage resistant and can expand and
contract as water freezes and thaws within the
tubing. No tubing material is freeze-break
proof, however, and PEX should be installed
using the same locally-prescribed insulation
requirements to prevent freezing of any plumbing
system.
Back
to top
How do I thaw
PEX lines?
When water
freezes inside PEX tubing, it can be thawed
using a hair dryer, warm wet rags or heat tape,
taking care not to overheat the tubing beyond
it's maximum recommended temperature.
Back
to top
Can PEX be
joined with solvent cement?
No. PEX cannot
be joined with solvent cement, or heat fusion.
PEX is installed using only mechanical fittings
either inserted in or around the tubing or by
compression fittings
Back
to top
|