Author(s) : Lawrence 1995 Edinburgh
Department of Manufacturing Enginineering and Design. University of East London, Dagenham Essex. RM8 2AS. UK. Abstract The phenomenon of rapid crack propagation in a pre-notched plastic pipes that are filled or partially filled with pressurised pas has now k e n incorporated into an indostrial requirement typically I...
Author(s) : Grigory, Kim, Kanninen, O'Donoghue, Mamo 1995 Edinburgh
The perceived need to ensure that polyethylene gas distribution pipes are safe from the possibility of long running catastrophic cracks has prompted a significant level of research recently. This paper brings to a completion an ongoing effort by the authors and their colleagues over the last few years. The...
Author(s) : Kitao, Hiarse, Nishimura, Inouge, Ishikawa, Otani, Miyasa, Kato 1995 Edinburgh
In this paper, the behavior of rapid crack propagation in gaspressurized polyethylene pipes was analyzed using the method in which two characteristic curves, i.e., the crack velocity and the gas decompression velocity, were compared. The crack velocity of 216mm outer diameter SDR13.5 medium density polyethylene...
Author(s) : Berthold, Boehm, Enderele, Groebel, Lueker, Lecht, Schulte 1995 Edinburgh
Recently Business Unit Polyethylene of Hoechst AG developed a Ziegler-catalyst-system providing very high catalyst activity even in presence of high hydrogen concentrations. The catalyst is applied to an appropriaie Z-stage-polymerization process. This technology is carried out in a modern, fully automated production...
Author(s) : Venizelov, Greenshields, Leevers 1995 Edinburgh
An analytical I-D model of the gas discharge process in the small scale steady State ( ~ 4 ) test for rapid g a c k propagation (RCP) in thermoplastic pipe has been developed. Because the gas can exert a powerful crack driving force, such a model is essential to an understanding of the test. This model yields a...
Author(s) : Nishimura, Suyama, Inoue, Higuchi 1995 Edinburgh
This paper describes an evaluatio~i metl~od for elearofusion joint strer~gtl~ and a basic co~~cept for determination of suitable fusion jointing col~ditio~~s. Firstly, the concept for estimating electrofusion joint strength is indicated. As an experimental result, it was found that the optimum fusion range lay...
Author(s) : Torsun, Day, Wound, Dib, Rosala 1995 Edinburgh
The Electro-Fusion welding of plastic pipes requires considerable knowledge and expertise in all areas associated with the technology, including the design of the fittings, design of the process parameters and the associated hardware, and joint preparation. On-site practice is also often difficult to control :...
Author(s) : Jones 1995 Edinburgh
In thispaper the mrfhorreviews the current situation with regard to the development of standards for Plastic Piping ystems. There are many detailed doc~tments/programmeswhich spec!& the exad status of ClWdS0 standards. gyou do not have access to them the Author will be pleased to answer spec~jicpoints. The development...
Author(s) : Vanspeybroeck 1995 Edinburgh
This investigation was initiated because the producers, users and testing institutes of the same PE compound recommended different procedures for butt fusion. The major difference was in the pressure to produce the weld. The difference was obviously reflected in the shape of the fusion bead as shown in Figure 1. The...
Author(s) : Dear, Brown, Mason 1995 Edinburgh
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) : Wagner, Siedlarak, Kropp, Fischer 1995 Edinburgh
A potable water installation using both DHP-copper and polypropylene as described in various German standards has been in operation now for seven years in an official building in Germany. These materials are used in both the cold and hot water section of the building. Plastic pipes have been installed as an...
Author(s) : Lawrence, Potter, Teo 1995 Edinburgh
This paper first outlines the case supporting the use of a fatigue based test method for plastlc pipes. listing the factors that have to be addressed in its use and by reference to a large body of other work justifies its adoption into the pipe industry. It then presents further evidence that support the case that...
Author(s) : Taraiya, Ward 1995 Edinburgh
The die-drawing process was developed in this laboratory to produce thick uniaxially or biaxially oriented products.'" Earlier efforts to produce oriented polymer tubes at Leeds University were based on hydrostatic extrusion. Hope et a17 showed that, by using a stationary mandrel and converging die arrangement, round...
Author(s) : Farshad, Flueler 1995 Edinburgh
In this contribution, some aspects of the huckling hehaviour of polymer pipes are treated; particular emphasis is placed on the hehaviour of pipes under lateral pressure. This work contains a classification of the failure cases in the plastic pipes due to instahility, a summary of some of the existing...
Author(s) : Williams 1995 Edinburgh
A review of the Fracture Mechanics methodology for characterising toughness is given. It is shown that the fracture resistance R is derived by computing an energy difference. It is noted that R is dependent on the constraint in the crack tip region and that this leads to the very complex behaviour observed in Charpy...
Author(s) : Pots, Benjamin 1995 Edinburgh
PVC products have suffered in the last years from attack by environmental activists. The production of PVC with its chlorine based raw material and the incineration of PVC with the suggested emission of dioxine have been used as arguments to try to curtail the use of PVC in all application areas. The PVC pipe...
Author(s) : Elzink 1995 Edinburgh
Pipelines, as used for their various applications appear to suffer frequently from deterioration. The combination of new products and advanced plastics materials ensures that pipe renovation can be carried out with increasing efficiency and decreasing environmental disturbance. Methods of renovation that currently...
Author(s) : Pittman, Farah 1995 Edinburgh
Once a grade of polymer has been specified for pipe production, the properties of the finished pipe depend on the processing conditions. By properties we mean here those attributes that will influence the in-service performance, and these can be grouped under three headings: Pipe geometry. To meet specifications and...
Author(s) : Evans, Loeppky, Rogers 1995 Edinburgh
This paper, the first of a series on the subject, is a critical review of the creep stiffness tests performed on structured wall pipes in the UK. The review is timely in light of proposed changes to creep stiffness criteria, and associated test methods, and the imminent publication of a new specification for...
Author(s) : Viebke, Gedde 1995 Edinburgh
The life of a stabilized polyolefin hot-water pipe may be divided into three phases denoted as Regimes A, B and C. Regimes A and B are characterized by different antioxidant consumption mechanisms. Regime C is defined as the time period from the stan of the thermooxidative attack on the polymer itself to the failure...
Author(s) : Frassine, Rink, Pavan 1995 Edinburgh
Creep fracture tests were canied out on a pipe grade polyethylene using arc-shaped notched specimens loaded in four point bending. Under all conditions examined, discontinuous crack growth was observed. The fracture process is analysed considering each single stage of the discontinuous crack propagation independently....
Author(s) : Bowman 1995 Edinburgh
The many technologies associated with the production, installation and uses of plastics pipes systems increase in their sophistication and diversity This paper selects and reviews changes that have and are taking place with polyvinyl chloride (PVC) and polyethylene (PE) pressure pipe systems designed for canying...
Author(s) : Castin, Tavernier 1995 Edinburgh
Polyethylene technology is advancing continuously. In the pipe sector, SOLVAY has led the way in the development of the third generation compounds of polyethylene classified MRS10 or PE100 materials. The advantages of PE100 are PE100 enables pipes of a given wall thickness to withstand higher pressure; or PE100 may...
Author(s) : Grigory, O'Donoghue, Mamoun 1995 Edinburgh
Measurements of temperature, power input, and pressure of the molten PE at the pipe-coupling interface in 4-, 6-, and 8-inch (1 14-, 168- and 219-rnm)' electrofusion (EF) couplings were made using instrumented experiments during the fusion cycle. The high temperature properties of several medium and high density...
Author(s) : Burn, Richards 1995 Edinburgh
Fracture toughness tests have been used with uPVC pipe for more than a decade. Standard methods of testing are described in British and ASTM Standards and in an I S 0 draft. Analysis of the British methods associated with the introduction of a fracture toughness test into joint Ausmlia/New Zealand Standards for...
Author(s) : Lawrence, Potter, Teo 1995 Edinburgh
The ultimate reliability of the data generated on tests, both static and dynamic, on "notched" plastic pipes samples is cmcially dependent upon the perfection of the actual notch root and the material immediately surrounding it. This paper d d e r s a number of the important factors relating to the production of the...
Author(s) : Greenshields, Leevers 1995 Edinburgh
Previous research has concluded that rapid crack propagation (RCP) cannot be sustained in 100% water pressurised pipe. However, this paper shows that by reducing the decompression wave speed in water to below the crack speed, it is possible t o sustain fast cracks in thermoplastic pressure pipe. T h e prediction of R...
Author(s) : Chambers 1995 Edinburgh
North West Water provides water and waste services to 7 million people in the north west of England; in so doing the company invests about E400M of capital each year. The Fylde Coastal Waters Improvements Scheme is a key component of NWW's f500M programme of investment on new and improved waste water systems aimed at...
Author(s) : Fitzpatrick, Mount, Smyth, Stephenson 1995 Edinburgh
The robustness of PVC-U pipes can be increased by blending PVC with chlorinated polyethylene (CPE). By varying the level of incorporation a spectrum of properties can be achieved. Data are presented which indicate that the tensile yield stress decreases with increasing amounts of CPE, whilst the fracture toughness,...
Author(s) : Stokes, Morris 1995 Edinburgh
At this Conference, the main focus is on the pipe : hardly surprising since this forms a large part of the material cost of a sewer, water, gas or fuel line. However, the pipe is often only a small part of the total cost of a pipeline installation. It is the jointing of the pipes to each other and to valves and pumps...
Author(s) : Hilger, Petry, Barbari 1995 Edinburgh
A deep understanding of the gap closing process during electrofusion is necessary to design electrofusion fittings (esp. couplers), which give best assumptions for good fusions on site. In one respect, measurements of temperature, melt-pressure and change of circumference during electrofusion and on the other hand...
Author(s) : Ovington, Stafford 1995 Edinburgh
This paper summarises a comprehensive study examining the factors which influence the weldability of crosslinked polyethylene W E ) whilst gaining an understanding of the nature ofjoints at a molecular level. Butt welding of XLPE to XLPE was investigated using both chemical @eroxide)and radiation crosslinked PE. The...
Author(s) : Headford 1995 Edinburgh
A novel polyethylene stub flange adaptor is described which allows size-for-size connection, in terms of the respective bores, to iron pipes or fittings. The end load performance of this product is significantly superior to that achieved with conventional polyethylene flanges, especially at large pipe diameters, and...
Author(s) : Cartwright, Troughton, Hinchcliff, Bowman, Jenkins 1995 Edinburgh
For the butt fusion joining of PE80 polyethylene pipes on site, long heat soak and cooling times predominate in the United Kingdom and other countries. The literature is reviewed to propose that these heat soak and cooling times can be significantly reduced via the use of machines with verifiable, reduced short...
Author(s) : Woodward, Pike 1995 Edinburgh
Holy Island (also known as Lindisfarne) lies off the North East coast of Northumberland and is separated from the mainland by a 5km causeway. It is cut off twice a day by the tides isolating the islanders from the mainland. Holy Island will be best known as the home of the Venerable Bede who wrote the first English...
Author(s) : Barbari, Hilger 1995 Edinburgh
Quality assurance (QA) systems according to IS0 9000 series are no longer the "privilege" of the suppliers to the plastic piping systems market. Also the endusers, in this case mainly gas distribution companies, are under-taking efforts to set up QA-Systems according to IS0 9000 series. Doing this more emphasis was...
Author(s) : Marshall, Hepburn, Netherwood 1995 Edinburgh
The adoption of polyethylene as a pipe material by both the gas and water indusmes has undoubtedly led to several sigruf~cant economic and operational advantages. The development of narrow trenching techniques and insertion refurbishment methods only became viable once a complete fusion jointed polyethylene system...
Author(s) : Tanaka, Akiyama, Komukai 1995 Edinburgh
This paper describes the influence of residual chlorine in potable hot water on durability of cross-linked polyethylene and polybutene pipes. The aim of this study is to find and verify proper testing procedures and evaluation methods to estimate service lives of plastic pipes under different concentration of residual...
Author(s) : Kenworthy, Harvey 1995 Edinburgh
The utilisation of underpressure electro-fusion Branch Saddles in gas and water distribution mains is well known and documented. To date the largest known Branch Saddles have been used for offtakes not greater than 125 mm . The advent of much larger underpressure Branching Saddles has enabled the industry to...
Author(s) : Troughton 1995 Edinburgh
This paper describes an initial programme of work to examine the feasibility of joining polyethylene pipe using the linear vibration welding technique. Commercial linear vibration welding equipment was used to join small lengths (100mm) of 125mm SDR11 PE80 and 180mm SDR17.6 PElOO pipe. Welds were achieved in total...
Author(s) : Janson 1995 Edinburgh
At the International Conference on Plastics Pipes W in Bath 1988, a paper was presented by the Author called : "Physical ageing of buried PVC sewer pipes as affecting their long-term behaviour". The tests performed on constantly deflected pipes referred to at that time had been running for approximately one year....
Author(s) : Kane 1995 Edinburgh
Severn Trent Water has a water mains distribution network of circa 40,000 kms in length. A major mains renovation programme has been underway since 1989 with over 7,500 kms of mains being rehabilitated. The triggers for this work were water quality, appearance, taste, structural condition, leakage and maintenance...
Author(s) : Leevers, Greenshields, Venizelos, Ivankovic 1995 Edinburgh
The development of pipe-grade materials to resist slow crack growth and ductile rupture has been spectacularly successful. It is a measure of this success that concern with Rapid Crack Propagation (RCP) has increased to the level evident at this conference. Stronger materials encourage the use of higher...
Author(s) : Isaac, Eccott, Pittman, Farah 1995 Edinburgh
This study has sought to characterise the variations in mechanical properties and residual stresses that develop as a result of the differential cooling rates that occur through the thickness of commercially produced polyethylene pipes. The mechanical behaviour has been studied through measurement of tensile...
Author(s) : Isaac, Eccott, Perridge, Pittman 1995 Edinburgh
A detailed investigation has been carried out on the microstructure of various polyethylenes recently developed for applications in the pipe industry. Of particular interest have been the PElOO formulations, and samples of these have been studied both from commercial piping and from laboratory produced plaques....
Author(s) : Knibbe 1995 Edinburgh
When we by to assess the applicability of plastics pipes. we normally start with the longterm hoop strength diagram. Although of course known to everybody. I show Figure 1 to make clear that I wish to consider both mechanical (bursting) failure and chemical failure. For polyolefins pipes, the life time is sometimes...
Author(s) : Bon, Gueugnaut, Marty 1995 Edinburgh
This paper presents the fust pan of the methodology designed by Gaz de France to assess for the prediction of the slow crack growth in polyethylene gas pipes by means of the so-called uvirolen test which allows one to monitor the length-wise development of a longitudinal crack in the pipe wall thickness after a...
Author(s) : Lowdon, Chantre, Brown 1995 Edinburgh
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...
Author(s) : Stafford 1995 Edinburgh
This paper is conceived as a review of current trends in the market and in the technology for thermoplastic pressure pipes. The application of any technical development depends on that subtle combination of the pull of needs and the push of new ideas. For more than 25 years British Gas has been actively involved in...
Author(s) : Monks 1995 Edinburgh
This paper describes the trial of a novel No-Dig water mains rehabilitation technique using "Polyester Reinforced Polyethylene" (PRP). The trial was carried out during July and August 1994 at Formby in the North West of England, where the water distribution system is the responsibility of North West Water Ltd....
Author(s) : Alferink, Guldback, Grootook 1995 Edinburgh
Wavin gained a lot of experience with operational PVC sewer pipes by monitoring installations and measuring pipe deflections over a period of about 35 years, as reflected in the database "PiPer". Some of the oldest pipes have been measured and dug up now to study the durability of these pipes. Furthermore the results...
Author(s) : Schmutz, Kramer, Zweifel 1995 Edinburgh
In recent years several specifications arose on determination of oxidation induction time (OIT) for polyethylene pipes. Depending on pipe applications, whether they transport water or gas at what pressure, an OIT of 10 to 20 min at an isothermal temperature of 200 or 210°C is specified. With such a specification it...
Author(s) : Ahlstrand 1995 Edinburgh
Pipes for the distribution of gas and water are generally installed underground, well protected from the destructive influence of UV radiation from the sun. So why bother about UV stabilization for products that will never be exposed to sunshine? Unfortunately the real world has its limitations. Even when business is...
Author(s) : Horne 1995 Edinburgh
Polyethylene for gas has always had an international flavour. When the first all-PE systems were built in this country in 1970 we imported pipe, fittings, tools and the instruction book complete from DuPont USA in two well-filled containers. Early experience was good and several of the independent Gas Boards, as they...
Author(s) : Ovington 1995 Edinburgh
Trenchless contractors throughout the world sometimes feel they have an uphill job trying to gain acceptance for non-disruptive technology. A major obstacle is that trenches, however dangerous and however much traflic chaos they cause, are cheaper. However with the implementation of the new Road and Street Works...
Author(s) : Hoving, Palmlof, Harget, Upperton, Ewing 1995 Edinburgh
The performance properties of Cross Linked Polyethylene (PE-X) are reviewed with particular emphasis on extreme temperature operation. Resistance to rapid crack propagation at low temperatures and retention of properties at elevated temperatures are highlighted. The potential availability of a high strength (MRS 12.5)...
Author(s) : Maine, Hicke 1995 Edinburgh
Due to space limitations on offshore platforms the treatment of well head fluids is expensive. To reduce the costs there is a move towards unmanned offshore platforms, or subsea completions. The result of such moves is that the pipelines are required to carry all produced fluids, including wet acid gases, in the...
Author(s) : Davitt 1995 Edinburgh
The needs of the water industry with respect to plastics pipes system are described, and the current situation of plastics pipes usage, along with future developments, is reviewed. The various stages in the process of introducing new materials are considered, and the associated d~ficultiesare highlighted. It is seen...
Author(s) : Engel 1995 Edinburgh
Polybutylene-l (PB) for pipe applications was first developed by Chemische Werke Huls in Germany in the early 1960's. 1965 several manufacturers were chosen by Huls to extrude pipes for trial installations - one of them was SALEN (today PIPELLFE) in Austria. Hiils sold it's PB-know how early 1970's. Mobil Chemical...
Author(s) : Kowalska, Wielgosz 1995 Edinburgh
ICRI in Warsaw elaborated the method of the powdered waste of vulcanized rubber management for thermoplastics porous hoses obtained by extruding, Porous hoses have excellent liquids and gases permeability. These hoses are applied in agriculture and horticulture as irrigation lines delivered water and nutrients....
Author(s) : Lind 1995 Edinburgh
The use of random copolymer polypropylene (PP-R) in hot water sanitary systems has grown substantially in Europe over the last five years. Borealis, which is a leading supplier of polyethylene and polypropylene for pipes and fittings, expects that the numerous benefits of PP-R over other materials will see this trend...
Author(s) : Choi 1995 Edinburgh
A plane strain specimen has been developed which creates a biaxial stress state when loaded in uniaxial tension. A detailed stress analysis of this specimen is presented. The stress state was generated though the use of a groove across the width of the specimen. Both theoretical and experimental results are presented....
Author(s) : Rose, Channell, Palmer 1995 Edinburgh
A series of PE 80 and PE 100 materials have been investigated to determine whether there exists a link between resistance to slow crack growth as measured by notched pipe test and creep of macroscopic oriented samples. Preliminary results suggests that there is a correlation between a single creep parameter and...
Author(s) : Hollins 1995 Edinburgh
PVC has been used for the manufacture of pipe for over 60 years and such pipes are now used on a worldwide basis for water distribution, effluent disposal, drainage, both highway and land, rainwater goods and cable ducting for telephone and other telecommunications purposes. Today about one and a half million tonnes...
Author(s) : Meijering 1995 Edinburgh
For reasons of environment and energy savings, the sales of High Efficiency Boilers have been stimulated in the last years. The low temperature flue gas emission which is characteristic for these boilers, leads to condensation of the flue gases in the chimney, attacking the masonry. The condensates contain aggressive...
Author(s) : Petersen 1995 Edinburgh
This paper presents the educational and personnel training system and ideas developed by Naturgas Syd i/S, based on the experience gained during the construction of natural gas networks and the company’s involvement in several countries as different as CZECH and Sweden. The system emphasizes personnel training,...
Author(s) : Greig 1995 Edinburgh
One of the main design criteria for limiting the operational pressures of polyethylene (PE) gas pipes is its resistance to rapid crack propagation (RCP) . Below a critical pressure the crack arrests but above the whole pipeline may be fractured. The paper discusses the critical pressures measured during European and...
Author(s) : Leijstrom, Ifwarson 1995 Edinburgh
This paper presents results and experiences obtained at Studsvik Material AB from the use of the Standard Extrapolation Method (SEM) according to I S O n R 9080. Results obtained from SEM calculations are demonstrated in creep rupture curves for pipe materials of PE, PP and PEX. Attention is also given to problems...
Author(s) : Crawford, Xu, Spence 1995 Edinburgh
Currently plastic pipes and fittings are manufactured by extrusion or injection moulding. However, in certain circumstances there are considerable advantages to be gained by using rotational moulding for these types of products. In particular, rotationally moulded products are stress-free, can have greater than...
Author(s) : Boot, Guan, Toropova 1995 Edinburgh
The Philosophy underpinning the concept of a polyethylene pipe lining designed to span small corrosion voids and longitudinal gaps in the host pipe is outlined, and provisional performance graphs for MDPE systems are given which indicate the potential savings that can be made under appropriate circumstances. Work...
Author(s) : Aoki 1995 Edinburgh
We have recently developed " D o u b l e - p i p e d r a i n a g e stack s y s t e m " which has a c o m p a c t n e s s of s p e c i a l d r a i n a g e c o n n e c t o r and the d r a i n a g e p e r f o r m a n c e of a traditional ventit'ated two-pipe s y s t e m . T h e d o u b l e - p i p e d r a i n a g e s t a...
Author(s) : Boot, Headford 1995 Edinburgh
This paper summarises current design practices for buried thermoplastic pipelines subjected to combined gravity and internal pressure loadings. It suggests that accurate predictions of stabilised deformations are neither possible nor necessary, but that appropriate structural design methodologies should instead...
Author(s) : Allwood 1995 Edinburgh
The industry has greatly benefinedfrom the use of plastics pipe systems. Understandinn - of - material behaviour,jointing and installation techniques has progressed to improve cost benefits. TLideal situation is that the user has a maintenoncefree system,fit for purpose with a long asset life, and the...
Author(s) : Marshall, Ingham, Brogden 1995 Edinburgh
When clients purchase plastics pressure pipes, they have frequently made that decision because they know that plastics do not corrode and they assume that if they do not exceed the pressure rating then a long lifetime should be assured. (Low cost has also been known to be a factor). It is thus of concern for the...
Author(s) : Marshall, Birch, Morley 1995 Edinburgh
Many UK Water Companies are now using PE pipe systems because it 1s believed that use of an all-welded pipe will minimise the number of mechanical fittings employed and therefore will reduce potential sources of leakage. With pipes such as ductile iron and PVCu, which are joined in short lengths, it is often...
Author(s) : Greenshiels, Leevers 1995 Edinburgh
The failure of a pipe by rapid crack propagation (RCP) can, by its nature, be highly desmctive and must be avoided. Research over the past ten years has concentrated on gas pressurised pipelines and has resulted in a greater awareness and understanding of the problem. Recent attention has focused on RCP in...
Author(s) : Gueugnaut, Rousselor 1995 Edinburgh
This paper presents the utilization of the so-called Stepwise Isothermal Segregation (SIS) tech nique for the characterization of 5 batches of gas pipes from a currently used.so-called 2nd generation MDPE from 1987 to 1992. The methodology allows one to eva luate the crystallization parameters of the resin at the...
Author(s) : Lamond 1995 Edinburgh
A general overview of the polyethylene market is given in relation to the use of non plastics materials. The advantages of using polyethylene pipe systems are highlighted. The value and success of polyethylene pipe systems to the utilities in economic and environmental tenns is discussed including the role of...
Author(s) : Pestrikov 1995 Edinburgh
In this paper the prediction test for a life it period of polymer pipes has been worked out and it is based on the prolonged fracture mechanics. A subcritical crack growth of the initiated defects, crack types in polymer material under the influencing of the external mediums, which model the exploitation conditions...
Author(s) : Beech, Headford, Hunt, Sandilands 1995 Edinburgh
The guldeUnes g h n in BS CP 312 :Pwt 2 : 1973 w e recommended to the UK toater industryfor the deslgn of polyethylene pfpeline systems to toke inin account the effects of tmnsient [surge) pressurejluctuatlons with respect to fatigue (ref.1). These guIdelInes we based on earlier experience wlth PVC-Usewer h i n g...
Author(s) : Channell, Clutton 1995 Edinburgh
A new method based on the Dugdale zone solution for finite geometries is presented to analyse the case of craze growth at the notch tip in Charpy impact experiments. It is believed that correct values of initiation toughness are calculated via this method, leading to greater confidence in the extrapolation technique...
Author(s) : Van der Grinten, Wichers-Schreur 1995 Edinburgh
Hydrostatic pressure testing 1s still the established method in evaluating the performance of plastics pipes. However, the introduction of new plastics materials with greatly improved properties causes hydrostatic pressure failure times to increase considerably. Evaluation of a new material delays introduction onto...
Author(s) : Cook 1995 Edinburgh
The properties of Hep30, an alloy of PVCU, PE and acrylic derivatives are described in terms of performance during handling and installation and performance during service. Details of tests demonstrate new levels of performance in the product and increased reliability in the long term properties of the plastic alloy....
Author(s) : Bjoerklund 1995 Edinburgh
Thermoplastic pipes have achieved a considerable share of the market over the years in the Nordic countries. PVC and PE pipes together account for more than 90% of the market for municipal water distribution lines and around 75% of the market for municipal drains and sewers. The consumption of plasticpipespercapitais...
Author(s) : Brown 1995 Edinburgh
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) : Pittman, Farah 1995 Edinburgh
Heat transfer coefficients for splay cooling in the manufacture of blue, yellow and black PE-80 and PE100 MDPE pipes are determined by measuring pipe surface tempemhtres in the annealing zones between splay tanks, and then fitting a computer simulation of the cooling process by adjustment of heat wander coefficients....
Author(s) : Munns and G.A, Georgiou 1995 Edinburgh
The use of polyethylene in the gas, water and chemical process industries has increased dramatically over the past two decades. This is largely due to the impetus provided by the British and American gas industries who have selected polyethylene as a material to replace metallic distribution pipelines. Apart from...
Author(s) : Wilson 1995 Edinburgh
The &ect of pipe wall thickness and welding parameters on the joint quality of bun fusion welded PElOO water pipes has been investigated using notched Charpy impact testing and tensile testing. The conventional U.K. Water Industry weld tensile test does not give a geometry independent measurement of weld ductility but...
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