|
|
PEX Tubing Comparisons - PEX-A - PEX-B - PEX-C Compared!
|
Comparisons between PEX-A and PEX-C versus other PEX-A, PEX-B & PEX-C
|
|
Property
|
HousePEX
PEX-A
|
HousePEX
PEX-C
|
Other PEX-A
|
PEX-B
|
Other PEX -C
|
|
Flexibility
|
Most flexible PEX than any other PEX tubing
meeting ASTM
|
More flexible than PEX-B and traditional PEX-A
|
Better flexibility than PEX-B
|
Stiffer to work and bend than PEX-A or PEX-C
|
Varies
|
|
Kinking resistance
|
Excellent
|
Fair
(More vulnerable to be Kinked than PEX-A)
|
Good
|
Poor
(Most vulnerable to be kinked than PEX-A or PEX-C)
|
Fair
(More vulnerable to be Kinked)
|
|
Kink Reparability
|
Excellent
|
Decreases after heating to transparency
|
Excellent
|
Not Possible
|
Decreases after heating to transparency
|
|
Strength
|
Meets ASTM and withstands higher inside
pressures than other PEX Tubing
|
Meets ASTM
|
Meets ASTM
|
Meets ASTM
|
Meets ASTM
|
|
Homogeneity
|
Excellent
|
Good
|
Not very good
|
Good
|
Good
|
|
Thermal Memory
|
Excellent
|
Poor
|
Good
|
Poor
|
Poor
|
|
Barrier property
|
Meets DIN 4726 (Measured 25 Times Better)
|
Meets DIN 4726
|
Meets DIN 4726
|
Meets DIN 4726
|
Meets DIN 4726
|
|
Thermostability
|
Better than ASTM requirements
|
Better than ASTM requirements
|
Better than ASTM requirements
|
Better than ASTM requirements
|
Better than ASTM requirements
|
|
Memory effect of being coiled
|
Easy to bend in any direction
|
Fair - Better than PEX-B
|
Fair - Better than PEX-B
|
Poor
|
Fair - Better than PEX-B
|
|
Minimum bending radius
|
Excellent - (Best of any other PEX Tube)
|
Good - Better than PEX-B
|
Good - Better than PEX-B
|
Poor - The worst of all PEX types
|
Varies
|
|
Density
|
0.930 - the lowest
|
0.941 - highest
|
0.938 - higher
|
0.941 - highest
|
0.941 - highest
|
|
Some of the Different PEX Tubing Sold in America
|
|
PEX-A
|
PEX-B
|
PEX-C
|
- HousePEX PEX-A
- Heat Link PEX-A
|
|
- HousePex PEX-C
- Embassy Industries, Inc.
|
|
HousePEX PEX-A & PEX-C Tubing Techs / Specs / Benefits
|
HousePEX™ PEX-A tubing is crosslinked using peroxide crosslinking, a so called PEX-a process. By means of
heat, a peroxide mixed into the PE raw material is split into radicals. These radicals react with the PE
polymer chain and absorb hydrogen atoms to become inert. The polymer chains now becomes radicals.
They, in turn, become inert by joining together - forming crosslinks.
As mentioned, the peroxide is split by means of heat. That means that the tubing material needs to be
quite hot for the reaction described above to take place. It must be well over the crystalline melting
point temperature of around 270°F. The material must also be correctly shaped (must have its tubing
form) while the crosslinking takes place inside the polymer melt. After crosslinking has taken place, the
material is cooled down and the crystals are formed around the crosslinking points, reinforcing these
areas.
These principles are valid for all PEX-A processes.
HousePEX™ PEX-C tubing crosslinking methods like radiation crosslinking (PEX-c) the
crosslinking takes place at temperatures below the crystalline melting point.
For other crosslinking methods like Silane crosslinking (PEX-b) the crosslinking takes place at
temperatures well below the crystalline melting point. For these methods, when tubing is heated over the
melting point, there will be a loss of crystals when the material is cooled down again. The crosslinks
will partially disturb the formation of previously existing crystals. So there will be a loss of strength
after this reheating - which is not the case for PEX-a tubing.
PEX-A is crosslinked while melted, and as described above, this will result in a lowered crystallinity.
Typically, a lower crystallinity means a lower strength. Therefore, the raw material utilized in traditional
PEX-a processes need to have a quite high density (which is practically the same as high crystallinity).
Typical raw material density is at least 0.950 kg/m3, and this results in density of around 0.939 kg/m3
after crosslinking. This is approximately the minimum density required in order to meet the ASTM F
876/877 strength requirements.
Radiation (HousePEX PEX-C) and Silane crosslinked tubing have densities that are approximately the same as the raw
material they are produced of - around 0.940 to 0.941 kg/m3. This is approximately the required minimum
for them to meet the ASTM PEX standards. Since density is directly related to stiffness (or flexibility)
we note that Radiation and Silane tubing are slightly stiffer than traditional PEX-a processes
(their density os approximately 0.002 kg/m3 higher - and this makes up a clearly noticeable difference.
The HousePEX™ PEX-A Tubing process starts with a raw material with a density of around 0.940 kg/m3 and the
final product has a density of around 0.930 kg/m3!! This is considerably less than other PEX process,
and results in a very flexible tubing. How is it possible that a material with this low density still exceeds
the ASTM requirements for PEX? The reason is that inventors of this process has succeeded to align
most molecular chains AROUND the tubing circumference! Traditional extrusion processes does not
provide any orientation of molecules, but their orientation are at random. By having the molecules
aligned around the tubing they are ready to absorb the stress caused by inside pressure. So in spite of
lower density this tubing can actually resist a higher inside pressure than traditional PEX tubing! At the
same time, since few molecules are stretched along the tubing, the flexibility is even better than what is
explained by the density alone! Welcome to test the pressure resistance. Just hook up our tubing in
series with a competitor's tube and increase the pressure until one of them bursts. It will not be the
HousePEX™ PEX-A Tubing.
Another major difference is the homogeneity. Traditional PEX-a processes have raw materials with high
density and high molecular weight making the polymer flow characteristics quite poor. The material is
mainly pushed through the extruders and raw material particles are just melted together. The flow is
very little stirred during the extrusion. Not so in the HousePEX PEX-A process. The material is thoroughly
worked, the original raw material particles are thoroughly blended, and even stretched out to orient the
molecules around the tubing. The result is excellent homogeneity, antioxidants well disbursed, and
better overall properties. Check homogeneity by holding tubing samples towards a bright light. Turn
slowly and look. You will notice the difference!
|
Click here to see our HousePEX PEX-A NSF listing information
- Backed by a 25 Year Manufacturer Warranty
- HousePEX® Tubing carries following ratings as issued by Plastic Pipe Institute: 73° F: 160 psi - 180° F: 100 psi - 200° F: 80 psi
- Manufactured in accordance with ASTM F 877 & ASTM F 876 ASTM F 877 - Bending Radius, ASTM F 876 - Tubing Strength
- Manufactured by LK-PEX (LK-PEX is the second largest manufacturer of PEX in Europe)
Click here to see our HousePEX PEX-C NSF listing information
- NSF Cl-TD Chlorine Resistance Performance for Potable Water Applications
- NSF Standard 61: Drinking Water System Components - Health Effects
- NSF Standard 14: Drinking Water System Components - Performance
- Manufactured in accordance with ASTM F 877 & ASTM F 876 ASTM F 877 - Bending Radius, ASTM F 876 - Tubing Strength
|
|
|
