FR0352

Mar 1993

I BENEFITS

To help derive maximum benefit from the FWR High Strength Plastics/HPPE research programme, particularly where there is a need to update the existing design, installation or operational guidance for PE pipelines.

This report examines the "Manual for the Design, Installation and Operation of MDPE Pipe Systems for Water Supply Distribution" and makes recommendations for the areas that will need to be addressed and updated as a result of the knowledge gained from the High Strength Plastics research programme.

The MDPE manual was first published in June 1986. Since then, a number of changes have occurred that will need to be addressed. Of particular importance are the following: _A new material, Higher Performance Polyethylene (HPPE), has been introduced into the market and an appropriate Water Industry Specification has been prepared. This material has greater long-term strength than MDPE and SDR 11 pipes can be used at pressures up to 16 bar, as against 10 bar for the equivalent SDR 11 MDPE pipes. Significantly improved rapid crack propagation resistance will mean that downrating above size 250 will not be necessary. This property, together with the extra strength should extend the acceptable size range and pressure capabilities of polyethylene pipe systems. _Electrofusion and butt fusion jointing are the methods of jointing most commonly used. Socket fusion jointing is now hardly used. The practical guidance required for butt fusion jointing has changed as a result of the introduction of the HPPE product.

Sections of the MDPE manual have been identified as requiring revision in order to bring it up-to-date with current practice.

V RECOMMENDATIONS

The recommended changes to the MDPE manual outlined in this report should be implemented. (Note: this will be the subject of an FWR programme in 1993/1994.)

This report is a compilation of recommendations for the update of the MDPE manual, developed as a result of the knowledge gained from the High Strength Plastics research programme.

Copies of the Report are available from FWR, price £15.00 less 20% to FWR Members