CONTROL OF SITE FUSION JOINTING OF MDPE PIPELINES
The aim of the work was to carry out a pilot study to evaluate the application of quality assurance principles to the control of site fusion jointing of medium density polyethylene (MDPE) pipelines.
MDPE is a relatively new material for the UK Water Industry requiring specialist jointing skills. Procedures for inspecting completed joints are relatively rudimentary, and sound workmanship is therefore of great importance. The pilot study was therefore carried out to determine whether the application of quality assurance principles to the task of site fusion jointing could assist towards the avoidance of failure costs and increase profitability.
Quality assurance principles were successfully introduced for the control of site fusion jointing. A number of discrepancies were identified during quality audits carried out which enabled improvements to the quality system to be identified and introduced. The report draws attention to the problems of maintaining good workmanship on site, and to training, and to the need for site supervisors to be aware of regular audit programmes. It also draws attention to costs and the practical issues involved in preparing and implementing appropriate control documentation.
The procedures developed during this exercise should be considered as a potential basis for the extension of quality assurance disciplines to other on-site activities associated with the installation and rehabilitation of water mains and sewers.
V RESUME OF CONTENTS
A Water Industry Specification is discussed which was developed to define procedures for the measurement of MDPE pipe fusion jointing performance. A pilot study is reported, set up within two divisions of Severn-Trent Water, to implement and audit site activity associated with both contract and direct labour using documented control procedures.
The results and cost/benefit analysis of the study are discussed to cover the whole MDPE fusion jointing activity from stores procedures through to final inspection.
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