Harmonisation of Polyethylene Pipe Buttfusion Procedures and Test Methods

Session 9B
11:00 am

Stephen Beech, SHB Consulting

Several well established procedures are used for butt fusion welding of PE pipes globally. ISO 21307 brings together Single Low Pressure, Dual Low Pressure, and the Single High Pressure procedures in one document. In the future these may be further rationalised to result in two or even one reference fusion procedure. Materials and machinery development is resulting in an increasing size range of pipe. Assurance of welding quality and accepted test procedures are required for such pipe.

The PE 100+ Association has established this project to evaluate the welding of large diameter thick walled pipe. The key to success is to ensure that the properties of welds are fully understood by means of suitable test methods.

After consultation with the industry, tests commonly used were reviewed. Tests on pipe assemblies and most tensile tests were discounted for stress distribution and geometry issues. The German DVS bend test, UK WIS tensile test with energy measurement, and the German DVS creep test to assess long term properties have been selected.

Weld samples using the three procedures and a ‘poor weld’ for comparison were produced from a 1200 mm pipe. Differences in performance have been identified in testing to date, and the relevance will be discussed in the presentation.

When the suitability of these tests for the full thickness range has been established, the relevant standards will be revised. At the same time the need for change and further harmonisation of the butt fusion procedures will be considered.

The project is being supported by members of the PE 100+ Association, assisted by product manufacturers, fusion equipment suppliers, test laboratories, and end users.

Stephen Beech – SHB Consulting, UK
Johannes Grieser – Hessel Ingenieurtechnik GmbH, DE
David Lowe – Exova, UK
Philippe Vanspeybroeck – Becetel, BE