Barrier vs. Non-Barrier PEX
Primary difference between Non-Barrier and Oxygen Barrier PEX is external coating of special polymer (EVOH), which purpose is to prevent gradual diffusion of O2 (oxygen) molecules into the water circulating in the heating system. This simple mechanism protects cast iron components of the heating system from rusting and contributes to higher operating efficiencies and longer lifespan of the parts.
The visual difference between these types is the glossy surface of the oxygen barrier PEX.
More about Oxygen Barrier PEX Tubing
The most common type of tubing used for radiant heat applications is the oxygen barrier PEX. The oxygen diffusion barrier coating of this radiant heat PEX prevents the oxygen in the atmosphere from permeating the pipe walls into the water to avoid over-saturation of the water with oxygen. For cost reasons, many of components in a typical radiant/hydronic heating system - from circulator pumps to heating elements and piping of the boiler are either cast iron or ferrous and are subject to rusting when in contact with oxygen. Without the oxygen barrier, only components made from non-corrosive material (such as stainless steel, brass, bronze) can be used in the system, subsequently increasing the costs of its initial installation and further maintenance.
PEX with oxygen barrier offers an effective and low cost solution for protection of ferrous parts in hydronic and radiant heat systems against rusting and corrosion.
Another type of radiant heat tubing is
PEX-AL-PEX.
Compatibility
Everhot barrier PEX is compatible with the following systems listed by popularity:
- Crimp Connection System - Brass Crimp Fittings (manufactured to ASTM F1807) or Poly Crimp Fittings (manufactured to ASTM F2159) and Copper Crimp Rings (manufactured to ASTM F1807) in conjunction with PEX Crimp Tools.
- Clamp Connection System - Brass (F1807) or Poly (F2159) PEX Crimp Fittings and Stainless Steel PEX Clamps (manufactured to ASTM F2098) in conjunction with Clamp Tools.
- Push-Fit (Sharkbite) Connection System - Quick connect/disconnect fittings which does not require tools or rings.
- Press Connection System - Special type PEX fittings with a stainless steel compression sleeve. Installed using press tools.
- Compression Type PEX Fittings - from certain manufacturers only, such as Matco-Norca
Sizes
1/2" oxygen barrier PEX is the most popular tubing size used in radiant heating systems, including installations under the subfloor (stapled to the bottom of the subfloor) and in concrete slabs (both reinforced and non-reinforced). Because of the relatively small diameter (5/8" OD), 1/2" PEX does not raise the floor level significantly and is flexible enough to ensure adequate coverage of the area with optimal heat distribution.
3/4" barrier PEX is commonly used for snow melt systems in driveways and walkways, since such systems require a higher flow rate with less restriction than traditional radiant heating systems. This size is also very common for supply and return lines to copper finned baseboards and cast iron or aluminum radiators.
1" PEX is generally used for supply and return lines to the boiler or the radiant heat manifold. Large internal diameter of 1" PEX allows it to transport substantial amounts of hot water to great distances, which makes it ideal for outdoor wood furnace installation.
3/8" size PEX is used in non-structural slabs (under tile) for residential radiant heating applications - bathrooms, kitchens, etc. It is a preferred size for smaller areas due to it's flexibility.
5/8" oxygen barrier PEX tubing sometimes replaces 1/2" tubing when project calls for higher heat loads or flow rates. It can also substitute 3/4" PEX in applications that require more flexibility and less flow (such as smaller snow melt systems).
Frequently Asked Questions
Q: Is Everhot Oxygen Barrier PEX Lead-Free?
A: No. Since it is not used in potable water applications, oxygen barrier PEX does not have to meet the SDWA low-lead requirements. For plumbing applications, Everhot Non-Barrier PEX can be used, which is Lead-Free and fully compliant with 2014 regulations.
Q: What Type/Grade is Everhot PEX tubing - A, B or C?
A: Type B.
"Grade" is not an appropriate term, since letters A, B and C refer to manufacturing methods (Peroxide for PEX-A, Silane for PEX-B and Irradiation for PEX-C) and are not an indicator of quality. In fact, when compared to PEX-A, PEX-B tubing exhibits less variation in wall thickness, higher bursting pressure, produces less waste during manufacturing, requires less energy to make and is more resistant to hydrocarbon oxidation.
Q: Can Everhot PEX be used for potable water?
A: Only Non-Barrier (Plumbing) PEX Tubing and PEX-AL-PEX tubing by Everhot are Lead-Free compliant and certified for potable (drinking) water use.
