Assessing the Structural Condition of PVC Pressure Mains

Reference: 15/WM/04/11
ISBN: 1 84057 786 X
Published Date: 26/08/2015

The water industry has a significant stock of PVC-U, PVC-O and PVC-A pressure mains some of which are now approaching the end of their 50 year design life. Additionally, early generation PVC-U mains have been shown to have a higher failure rate than anticipated.

This report sets out a description of the failure mechanisms of PVC pipes, reasons for their premature failure and describes the various methods of testing the mechanical characteristics of existing PVC pipe materials.

The report also investigates the various NDT methods that could be used to assess the condition of these pipes and provides guidance on future avenues of research that could be pursued in this area.

Air Valve Management

Reference: 13/WM/04/10
ISBN: 1 84057 703 7
Published Date: 23/12/2013

Ineffective air management in pressurised water networks can cause reduction in capacity, bursts, contamination and other water quality problems, which can lead to customer supply interruptions and water quality complaints. Detailed studies of these issues by means of a comprehensive literature search, water company questionnaires and field trials on real network distribution networks have led to the production of this report which contains the study findings together with a guidance document on the design and maintenance of air valve installations and an associated cost benefit analysis spreadsheet which users can customise to develop the most economic programmes of work.

Techniques for Preventing Interruptions to Customer Water Supplies

Reference: 12/WM/04/9
ISBN: 1 84057 630 8
Published Date: 24/05/2012

Customer expectations in terms of quality of service are rising; as such, customers are increasingly intolerant of interruptions to their water supplies. This increasing expectation is reflected in the introduction of the Service Incentive Mechanism and the requirement for more detailed reporting of interruptions to Ofwat. The water industry has developed a number of methods for working on mains under pressure to prevent interruptions, but there is a wide difference in the application of these techniques across the industry. This report evaluates the under pressure techniques that are currently available to the water industry, as well as reviewing those used in the Oil and Gas industry to assess what new techniques could be developed. A Decision Support Tool has also been developed to assist the practitioner in determining the relative cost effectiveness of under pressure techniques versus conventional methods, taking into account the impact of causing interruptions.