Applications & Jointing
Plastic Pipes Conference Association # 1995 Edinburgh
Lowdon, Chantre, Brown
The Water Distribution Technical Centre
Lyonnaise des Eaux operates a network of three water distribution technical centres which serve the needs of the Lyonnaise des Eaux Group in the area of potable water distribution technology. The main centre, known as the Water Distribution Technical Centre (WDTC), is based at North East Water's Head Office in Newcastle upon Tyne. Part of the remit of the WDTC is to assess new materials appearing on the market for their suitability to the Lyonnaise des Eaux Group. This, coupled with the findings of the 1992 research study as outlined below’, were the primary catalysts for the collaboration between North East Water and Uponor over Molecularly Orientated PVC (MOPVC), a collaboration which began in 1992 and which continues apace today.
Materials Selection Strategy
In recent years, a number of studies have been carried out by Lyonnaise des Eaux which have revealed the value of developing systematic and consistent approaches to pipeline materials selection. One such study''’, commissioned in 1992 as part of the Lyonnaise des Eaux applied research programme, investigated the economics of laying three different types of pipe material - Polyethylene, PVC and Ductile Iron, over a range of diameters. The results, which do not include reinstatement costs, are shown in Fig.1.
From the graph, it can be seen that over the range of most commonly laid diameters (<315mm dia.), PVC is the most economic material to lay, based purely on cost per linear metre. There are, however, other factors which must be taken into consideration when making one's choice.
Related papers
Author(s) : Troughton, Brown, Hessel, Piovano
As part of the Polytec Systems European-funded project, electrofusion (EF) joints in polyethylene (PE) pipe, containing different flaws, have been subjected to various standard and non-standard, long-term and short-term, coupon and whole pipe tests. The results were compared to determine which tests could discriminate...
Author(s) : N. Brown
The three major requirements for a gas pipe resin are (1) the MRS , (2) excellent resistance to slow crack growth[SCG] and (3) resistance to brittle fast fracture as exhibited by a low S4 critical temperature,[Tc]. In order to develop a new PE resin, it is necessary to investigate many variables involving the...
Author(s) : Brown, Lu
The S4 critical temperature (CT) for 110 mm pipe was correlated with the plane stress impact energy for 13 resins. A plane stress impact (PSI) test is offered as an inexpensive way to control RCP by determining the lot to lot variations of the critical temperature of a resin. Details of the PSI test are presented.
Author(s) : Dear, Brown, Mason
The threshold load to just maintain crack propagation and conditions for catastrophic failure, should the material be loaded above this threshold, are two key evaluation requirements when assessing polymers for pipe applications. Often these assessments need to be made during material research and development and...
Author(s) : Brown
ASTM D2837 and ISO/TR 9080 for validating PE resins were analyzed. It was found that the difference between 11.3 yr. and 50 yr. as specified in D2837 and ISO/TR 9080, respectively, has very little effect on the determination of the Long Time Hydrostatic Strength (LTHS) at the service temperature, but this difference...
Author(s) : Brown, Lu
The test, called PENT, consists in measuring the resistance to slow crack growth of precisely notched specimens under constant load in air. The specimen geometry is designed and conditions are chosen so that failure is by slow crack growth as occurs under service in the field. The test conditions for producing failure...
Author(s) : Brown, Lu
Two of the pipe resins that are commonly used in the USA are compared with respect to their relative life times. The improvement in the performances of the currently used materials compared to the older material from the same producer have been measured. T h e 1ahoratoi-Y conditions for producing brittle failure in...
Author(s) : Brown
Slow crack growth in polyethylene involves one of the most complex fracture processes in the field of fracture mechanics and especially; very little is known about the initiation mechanism. It is generally believed that there is a critical value of the stress intensity, K, below which crack growth does not occur in...
Author(s) : Brown
An early record of the use of a l'plastictl or flexible pipe is in 1733 when the Re\/. Stephen Hales wished to measure the blood pressure of a horse. He had a brass canula, to insert into an artery, and a long glass tube; but he had to find a flexible pipe to connect the two. His solution was to use the trachea, or...