Standard & approval

EN 681 – Elastomeric seals for water

EN 681 · Elastomeric seals for pipe joints in water supply and drainage

EN 681 sets out the material requirements for elastomeric seals in pipe joints used in water supply and drainage. For drinking water seals, it is the relevant material standard.

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Field

Drinking water

Subject

Material requirements

Part 1

Vulcanized rubber

Complemented by

KTW-BWGL · DVGW

Overview

EN 681 is the European standard for elastomeric seals in pipe joints used in water supply and drainage. It specifies the mechanical and physical properties a sealing material must meet so that a pipe joint stays tight for decades. For seals in drinking water it is the relevant material standard; for gas, EN 682 applies.

The parts of EN 681

Part	Material
EN 681-1	vulcanized rubber (e.g. EPDM)
EN 681-2	thermoplastic elastomers (TPE)
EN 681-3	cellular materials of vulcanized rubber
EN 681-4	cast polyurethane sealing elements

Which requirements are tested?

Hardness and hardness tolerance
Tensile strength and elongation at break
Compression set at different temperatures
Stress relaxation (sealing force over time)
Volume change in water
Behaviour after ageing and ozone resistance

EN 681 and drinking water hygiene

EN 681 describes the mechanical requirements for the material. Hygienic suitability for contact with drinking water is demonstrated separately: in Germany via the KTW-BWGL and the microbiological test method to EN 16421 (W270), in future complemented by the EU DWD. Certification is often carried out by the DVGW.

Which seals does EN 681 cover?

Sealing rings and crush seals for pipe joints
Hose rings and profiles in water-carrying systems
Moulded parts and O-rings for fittings

For drinking water seals we recommend our EPDM blue. Testing to EN 681-1 is in preparation; the compound is already KTW-BWGL compliant.

FAQ

The key questions

What does EN 681 apply to?

EN 681 sets out material requirements for elastomeric seals in pipe joints used in water supply and drainage. For seals in drinking water, it is the relevant material standard. For gas, EN 682 applies.

Which parts does EN 681 have?

Part 1 covers vulcanized rubber, part 2 thermoplastic elastomers (TPE), part 3 cellular materials of vulcanized rubber and part 4 cast polyurethane sealing elements. For most EPDM seals, part 1 is relevant.

What is tested under EN 681?

The mechanical and physical properties of the material are tested, including hardness, tensile strength and elongation at break, compression set, stress relaxation, volume change in water, behaviour after ageing and ozone resistance.

Is EN 681 sufficient for use in drinking water?

No. EN 681 describes the mechanical requirements. In Germany, hygienic suitability for contact with drinking water is demonstrated via the KTW-BWGL, in future complemented by the requirements of the EU DWD.

Which material is suitable for EN 681 in drinking water?

For drinking water seals we recommend our EPDM blue. Testing to EN 681-1 is in preparation; the compound is already KTW-BWGL compliant.

Applications