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Oxygen Barrier PEX tubing vs. Non-Barrier PEX tubingOxygen barrier PEX offers the significant feature that prevents the corrosion on cast iron parts which are commonly used in heating systems (circulators, boiler heating elements, radiators etc.)
The size of the tubing is estimated by the application type and the size of the tubing. It is determined by the engineer who designs radiant heating system. ½ PEX is the commonly used tubing size and is used for sub floor installations and radiant heating installations, concrete slabs, engineered floors and sandwich type installations.3/4 PEX is used for snow melt system as these systems require higher flow rate of the radiant heating system.1" PEX is commonly used to supply & return lines to the boilers or radiant heat manifold. This size allows transporting huge amounts of water to distant places. This size is perfect for outdoor wood installation of furnace. Another size which is available is 3/8' inch which is used in non structural slab. It is a preferred choice in smaller areas as it provides flexibility.
PEX tubing is a non barrier PEX-B
This tubing has received the certification for potable water applications. It is used for light commercial potable plumbing systems.
One of the commonly asked questions before initiating the plumbing or a radiant heating system is which PEX tubing to be used, whether PEX tubing with non- barrier or oxygen barrier.
The major difference between the oxygen and the non barrier PEX tubing is external coating of oxygen barrier PEX tubing and this makes tubing prone to oxygen diffusion. Oxygen barrier is used in hydronic or radiant heating applications. In these systems the ferrous and iron components are already present. When the oxygen molecules get in touch with the water along with the ferrous parts of system it results in rusting. Oxygen barrier helps in preventing ferrous components from corroding. The Oxygen barrier is known by EVOH (Ethylene Vinyl Alcohol) and this is the simple abbreviation of a polymer. On the oxygen barrier PEX tubing one can find the imprint of DIN 4726 which is standard. This standard shows that the oxygen diffusion requirements are completely met.
Non barrier PEX tubing has its use in plumbing applications. In this there is no need for oxygen barrier as the oxygen molecules would be present in the system always as there is a constant supply of fresh water from water main or water heater.
One can identify the PEX tubing by bringing it to light and taking a closer look. If this tubing is with the shiny surface then it is oxygen barrier and if it has a matte surface then it is non barrier. When purchasing tubing one should not get confused with the colors as these colors are used for coding purposes only.