EVOH is an oxygen barrier material
EVOH stands for ethylene vinyl alcohol copolymer. It is a specialized polymer with low gas permeability. Oxygen cannot pass through the EVOH layer. PEX EVOH pipes use EVOH to block oxygen diffusion.
How EVOH blocks oxygen
EVOH has a dense crystalline structure. This structure prevents gas molecules from passing through. Oxygen molecules are too large to penetrate the EVOH layer. PEX EVOH pipes rely on this physical barrier.
Oxygen diffusion process
Oxygen naturally diffuses through plastic pipes. It enters from the atmosphere into the water. This process is called permeation. PEX EVOH pipes prevent this permeation completely.
Why oxygen is harmful
Oxygen in water causes metal corrosion. Boilers, pumps, and pipes can rust. Oxygen also supports bacterial growth. PEX EVOH pipes protect systems from these problems.
EVOH layer location
The EVOH layer is in the middle of the pipe wall. Two PEX layers surround and protect it. Adhesive layers bond everything together. PEX EVOH pipes have the EVOH barrier in the center.
Barrier effectiveness
EVOH reduces oxygen permeability by over 98%. Standard PEX allows up to 100 mg/m²·day. EVOH layers allow less than 0.1 mg/m²·day. PEX EVOH pipes are highly effective oxygen barriers.
Example: heating system protection
A heating system uses PEX EVOH pipes for distribution. The EVOH layer prevents oxygen from entering. The boiler remains rust-free after 10 years. Example: a durable, corrosion-free heating system.
Example: standard PEX system
A heating system uses standard PEX without barrier. Oxygen enters the water through the pipe. The boiler shows corrosion after 5 years. PEX EVOH pipes prevent this problem.
Meeting DIN 4726 standards
German standard DIN 4726 requires oxygen barriers. Permeability must be below 0.1 mg/m²·day. PEX EVOH pipes meet this standard easily. Example: approved for use in German heating systems.
Protecting metal components
The barrier protects pumps, valves, and heat exchangers. Corrosion is prevented or minimized. Equipment life is significantly extended. PEX EVOH pipes protect the entire system.
Maintaining water quality
The barrier prevents bacterial growth in the water. Oxygen promotes bacterial proliferation. The water stays clean and clear. PEX EVOH pipes maintain water quality.
Final EVOH role summary
The EVOH layer in PEX EVOH pipes prevents oxygen diffusion. It is a dense polymer with low gas permeability. Oxygen cannot pass through the EVOH barrier. This protects metal components from corrosion. It also prevents bacterial growth and maintains water quality. PEX EVOH pipes meet DIN 4726 oxygen barrier standards. The EVOH layer is essential for heating and plumbing systems. Example: a reliable, long-lasting oxygen barrier solution.