PE-RT Oxygen Barrier Pipe: 5-Layer Underfloor Heating Guide

Oxygen-barrier PE-RT pipe contains an EVOH barrier layer designed to limit oxygen permeation into a closed-loop heating system. The barrier requirement should be checked carefully in underfloor heating projects that contain pumps, boilers, manifolds and other metallic components.

How does the five-layer structure work?

In five-layer PE-RT pipe, the EVOH oxygen barrier sits between the inner and outer PE-RT layers. Two adhesive layers provide adhesion between the different materials. The layers and their functions, from outside to inside, are:

SPK five-layer PE-RT pipe cross-section: outer PE-RT, adhesive layer, EVOH oxygen barrier, adhesive layer and inner PE-RT. — Layers of SPK five-layer oxygen-barrier PE-RT pipe, from outside to inside. Schematic illustration; layer thicknesses are not to scale.

Outer PE-RT layer: Forms the pipe's outer surface and helps protect the EVOH barrier inside from external influences.
Adhesive layer: Provides adhesion between the outer PE-RT layer and the EVOH oxygen barrier.
EVOH oxygen barrier: Helps limit oxygen permeation through the pipe wall into the heating circuit.
Adhesive layer: Provides adhesion between the EVOH oxygen barrier and the inner PE-RT layer.
Inner PE-RT layer: Forms the inner surface in contact with the heating water and carries the water through the circuit.

What does an oxygen barrier do in PE-RT pipe?

Oxygen entering through a plastic pipe wall can increase the corrosion risk for ferrous components in a closed circuit. The EVOH layer helps limit this permeation. If a project specification refers to DIN 4726 or another oxygen-permeability criterion, request the current product data sheet and applicable conformity documents.

Standard PE-RT vs 5-layer oxygen-barrier PE-RT

Option	Main feature	What to verify
Standard PE-RT	Flexible pipe for heating and warm-water applications	Whether the project requires an oxygen barrier
5-layer oxygen-barrier PE-RT	Multilayer construction with an EVOH barrier	Required standard, system components and application class
PE-RT with conduit	Spiral conduit for mechanical protection and routing	Whether conduit and oxygen barrier are each specified

Underfloor heating pipe selection checklist

Pipe dimension and wall thickness
Design temperature and operating pressure
Oxygen-barrier requirement
Loop length, pipe spacing and hydraulic calculation
Compatibility with the manifold and connection fittings
Pressure test and installation procedure before screed
Required standard, certification, packaging and total length

Loop length and pipe spacing are not fixed product values. They must be determined by a qualified designer from the heat-loss calculation, floor finish and system design.

Frequently asked questions

What does the oxygen barrier do?

The EVOH layer helps limit oxygen permeation through the pipe wall into a closed heating circuit. This helps reduce the risk of oxygen-related corrosion in ferrous components. Check the barrier requirement and applicable conformity documents against the project specification.

Does spiral conduit replace an oxygen barrier?

No. Spiral conduit provides mechanical protection and helps with pipe routing; the oxygen barrier has a different function. If the project specifies both, select a pipe with both an oxygen barrier and spiral conduit.

How are loop length and pipe spacing determined?

No single length or spacing suits every project. Heat loss, floor finish, pipe dimensions, design temperatures, flow rate and pressure loss must be considered together. A qualified designer should determine loop length and pipe spacing from the system design calculations.

SPK PE-RT product options

Request a technical data sheet and quotation

Share the destination country, total length, pipe dimensions and project specification through the SPK enquiry form. Request the current technical data sheet, the conformity documents required for your project and a quotation to support product selection.