Author(s) : Morgan, Muckle, Scott 1998 Gothenburg
A three way partnership has resulted in the development of a new solution to the refurbishment of old iron and steel gas service pipes. The solution which has been developed allows a flexible polyethylene replacement pipe to be inserted into the old pipe system. This avoids the need for the costly excavations or...
Author(s) : Lawrence, Rasbash, Potter, Teo 1998 Gothenburg
Structured wall plastic pipe has been in existence for many years, but there remains a need for an appropriate method for assessing the durability of their comparatively thin walls in actual service. In normal operation this has not manifest itself as a problem, but the fact that damage can be sustained during...
Author(s) : Lawrence, Potter, Teo 1998 Gothenburg
The short term testing of any plastic pipe for its prospective longevity in service is extremely difficult because it requires some accelerated technique which needs to work within or verv close to the normal operatin? strains if extensive creep processes are to be avoided. The problem has now been exacerbated by the...
Author(s) : Gutoneau 1998 Gothenburg
Polva Pipelife B.V. Holland is a producer of plastic pipe systems. The company belongs to the Pipelife Group based in Austria. In 1993 Polva Pipelife introduced a new product in the Dutch gas market with the name Polsafe. Whilst this system was designed for the connection of service lines to high impact PVC mains,...
Author(s) : Dreze, Scheelen 1998 Gothenburg
The expanding use of tough high-density polyethylene for gas and water pipes requires the develo~m~ent of new test methods for performance evaluation. This paper investigates the suitability of one of the proposed test methods, the Full Notch Creep Test, as a tool for material performance assessment, quality control...
Author(s) : Gray, Powell, Bonner 1998 Gothenburg
Aliphatic polyketones are a family of polymers prepared by the polymerisation of olefins and carbon monoxide in a perfectly alternating sequence. BP Chemicals produces these materials using a proprietary palladium catalyst in a continuous polymerisation process. They are crystalline thermoplastics which offer a...
Author(s) : Broutman, Edwards, Shah, Palermo 1998 Gothenburg
The Alternate Methods Committee of the Plastics Pipe Institute's Hydrostatic Stress Board (HSB) has initiated development of an alternate method for determining the hydrostatic design basis (HDB) for plastic piping materials. After reviewing several test methods, the plane-strain tensile method, developed by Choi and...
Author(s) : Hill 1998 Gothenburg
It is almost 30 years since BG ple (formerly British Gas) installed the first polyethylene gas distribution pipeline in the United Kingdom. At that time, there was little experience in the failure mechanisms associated with PE materials and therefore the predicted lifetime, although scientifically sound in approach...
Author(s) : Taraiya, Ward 1998 Gothenburg
Over the last decade Leeds University has developed a continuous die-drawing process to produce thick uniaxially and biaxially oriented polymeric products. Die-drawing offers a simple and effective route to stronger and stiffer polymer products. Biaxially oriented pipes with their improved hoop strength offer...
Author(s) : Hinchcliff, Troughton 1998 Gothenburg
There are a number of different mechanical test methods available to assess the quality of butt fusion welded joints in polyethylene (PE) pipes. However, little published information exists on the correlations that may or may not exist between the results from these methods. This paper compares the results from five...
Author(s) : Valta, Syrjaelae, Karttunen, Phillips, Kirjavainen 1998 Gothenburg
A novel extrusion technology is introduced for multilayer plastics processing. Starting point of this work has been well known problems with conventional extrusion heads : the marks from the spider legs and weld line of cross head remain in the product and weaken mechanical and electrical properties. Uniform flow in...
Author(s) : Gibson 1998 Gothenburg
This paper discusses the fabrication and properties of continuous fibre reinforced thermoplastic pipe systems. Such products can be manufactured by various winding processes involving reinforcing fibres or prepreg tape and have the potential to form the basis of a new range of high added value pipe products.
Author(s) : Tsunaga, Matsunami, Sato, Nakata 1998 Gothenburg
By applying the cross-linked EF to the cross-linked PE(PEX) pipe \vhicli has a composite structure, the reliability of hot water piping system under severe environment lias significantly increased. A continuous use for approsimately 30 years under severe conditions such as 80 "C. and I MPa becomes possible. In this...
Author(s) : Janson 1998 Gothenburg
Sustainable Development’ is a concept which is often used today, particularly when discussing necessary efforts for preventing persistent environmental problems. It came up as a result of the findings already by the Rome Club et al in the early 70s’, implying that the natural resources of the earth are limited and in...
Author(s) : Alferink, Janson, Olliff 1998 Gothenburg
Extensive field trials are being performed in a project sponsored by TEPPFA and APME,to obtain well documented information about the behaviour of buried thermoplastics pipes. as outlined in the paper by Alferink, Bjorklund and Kallioinen (Ref 1). This information is of vital importance to obtain a workable design...
Author(s) : Yoshida, Kitaoka, Nishimura 1998 Gothenburg
Because dirt ( sand, mud, etc. ) on the fusion interface causes a decrease in the strength of fusion joints, it is necessary to scrape and clean the pipe surface before fusion jointing. We have determined the degree of dirt that causes a decrease in the strength of fusion joints by experiments on peeling off at the...
Author(s) : Hillmansen, Davis, Leevers 1998 Gothenburg
Rapid Crack Propagation in PE-100 gas pipes is governed primarily by a brittle-tough transition temperature TBT,above which ductile deformation will absorb energy and promptly arrest a fast-running brittle crack. Even at low temperatures, a layer of plastically deformed material is formed at the pipe bore during...
Author(s) : Lawrence, Teo, Potter 1998 Gothenburg
There is increasing evidence that dynamic testing is a most powerful. if not the only practical, method of evaluating whole plastic pipe for its long term service potential. Indeed in some instances this method is used as the primary indicator of performance in the researcNdevelopmentaI process of these products :...
Author(s) : Lawrence, Potter, Teo 1998 Gothenburg
When butt welds fail in servicc it is normal to find that the initiation site of the fracture occurs at the point where the roll bead attaches to the main body of the pipe. The ratio of hoop stress to longitudinal stress for 'thin walled' pipe is approximately 2 : 1 and so it is more likely that these transverse...
Author(s) : Kuriyama, Narisawa, Shiina, Kotaki 1998 Gothenburg
Unplasticized polyvinylchloride (PVC-U) is extensively used in the pressure pipe applications. These pipes are usually designed to have 50 year lifetime. Although their service performance is generally very satisfactory , there has been a number of cases where the pipes fail at unexpectedly short times. One of the...
Author(s) : Lu, Burn, Whittle 1998 Gothenburg
For rubber ring joints to resist plant root penetration, it has been reported and promulgated into Australian Standards that a sufficiently high contact pressure between the rubber and the pipe must be maintained. The evaluation of the appropriate interfacial pressure to be used has been under discussion for some time...
Author(s) : Mitosek, Roszkowksi 1998 Gothenburg
Thanks to a number of beneficial properties, plastics pipes are widely used in the construction of pipelines. Very low absolute roughness, high wall resistance to aggressive agents (contained 111 soil and in the liquid stream) and simple assembly cause these pipelines to be cost-effective both in construction and...
Author(s) : Bagge 1998 Gothenburg
As the Environmental matters gain more attention, laws and regulations building on the principle of Sustainable Development emerge both on national and EU level. This concerns product applications as well as their chemical constituents. In the Nordic building and construction industry new interest has emerged after...
Author(s) : Wikkerink, Wolters, van den Berg, Huppes 1998 Gothenburg
Environmental aspects tend to be increasingly important in designing gas distribution systems and in selecting gas distribution materials. Therefore the environmental aspects of various materials options for gas distribution networks were analyzed by means of a quantitative life cycle assessment. This paper describes...
Author(s) : Wolters 1998 Gothenburg
In the Netherlands, rigid PVC and impact-modified PVC pipes have been used in gas distribution systems for dozens of years. In general, these pipes have performed excellently. Some years ago, however. questions were raised about the resistance of these materials to certain gas constituents. An extensive research...
Author(s) : Okamoto, Akiyama, Wasada, Komukai 1998 Gothenburg
Resistance of PE gas pipes to rapid crack propagation (RCP) was evaluated by S4 testing and a correlation of ductile brittle transition temperature between S4 testing and Charpy impact testing was investigated. S4 tests for Japanese domesticmade PE gas pipes (medium density) of five materials and three outer...
Author(s) : Marshall, Brogden, Shepher 1998 Gothenburg
Many early brittle failures in PVC water and sewerage pipelines, where repeated surge events are thought likely to induce embrittlement, were attributed to fatigue. The concerns of pipeline engineers led to the adoption of the British Standard Code of Practice CP 312 (ref. 1) by the UK water industry, which gives...
Author(s) : El-Sobky, Psimolophitis 1998 Gothenburg
Plastics pipes are used extensively by the gas and water industries. Fibre reinforced thermoplastics are widely used for the manufacturing of precision engineering components by injection moulding and to a lesser extent in pipe extrusion. The main reason for this is that the uniaxial flow of the fibre filled polymer...
Author(s) : Venizelos, Greenshields, Ivankovic 1998 Gothenburg
Over 30 years ago, fast brittle fracture was identified as an inherently catastrophic failure mode in pressurised plastic gas pipelines. Although fast cracks seemed difficult to initiate, subsequent rapid crack propagation (RCP) was thought to be possible at pressures lower than the rated pressure, imposed by design...
Author(s) : Greenshields 1998 Gothenburg
Brittle failures in service water pipelines sometimes occur at relatively low pressures and for no apparent reason. This paper presents a review o f research into brittle fracture in water pipes and questions some o f the received assumptions which obscure tlie subject. The hydrostatic S4 test is proposed to measure...
Author(s) : Reynolds, Jenkins, Burgess, Attwood 1998 Gothenburg
The Butt Fusion procedures used in the UK Water and Gas industries, which determine the total time taken to complete a successful joint, have remained largely unchanged since their harmonisation in 1990. The parameters evolved to suit manually operated Butt Fusion machines and reflected the fact that the...
Author(s) : Otto, Schulte, Feldmann 1998 Gothenburg
The development of a large aeroplane with two decks and a capacity of more than 500 passengers yields numerous problems in structural design, logistics, passenger systems etc., including special requirements for the fresh water supply system. The reliability of this system is very important, especially during long...
Author(s) : Wolfe 1998 Gothenburg
The development of Marlex" H5 16 high performance HDPE pipe compound progressed over many years resulting in the introduction of Driscopipe 8100 pipe to the United States pipe market in 1997. This product has been extensively evaluated for long-term hydrostatic strength (LTHS). slow crack growth (SCG). environmental...
Author(s) : Tonen 1998 Gothenburg
Safe operation of Transco's gas distribution system depends upon an ongoing policy to replace cast iron mains with polyethelene pipe. Minimal excavation techniqlles can ensure that this work is carried out in a cost effective manner. Research and development of techniques to achieve this objective are key to...
Author(s) : Douglas, Leevers 1998 Gothenburg
A model for dynamic and impact fracture has been recently proposed whereby the fracture event is controlled by adiabatic heating and subsequent melting of the cohesive crack tip craze. The crack initiation resistance is shown to be an inherent function of specimen geometry and impact speed. This theoretical framework...
Author(s) : Brown, Lu 1998 Gothenburg
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) : Pinter, Lang 1998 Gothenburg
In this work differently stabilized Poly(ethylene) (PE)-types were characterized by linearelastic fracture mechanics (LEFM ) (creep crack growth tests) and internal pressure testing. In total, 6 PE formulations (2 polymer types with 3 stabilizer systems) were investigated. While no influence of stabilizer type was...
Author(s) : De Rosa, Lane 1998 Gothenburg
The systems reviewed below refer predominantly to the use of PE pipe, as this is the material of choice for many of the applications described. Recent developments in other pipeline materials have introduced the possibility of using alternatives to PE in these applications where there is a cost-benefit of doing so....
Author(s) : Berndtson 1998 Gothenburg
This paper has been written to support the Workshop presentation. It is intended to be a useful reference and introduction to plastics pipeline systems for the engineer, specifier or end-user of plastics pipeline systems. The basic characteristics and types of plastics have been reviewed. The reasons why plastics...
Author(s) : Headford 1998 Gothenburg
Jointing Methods for Plastics Pipeline Systems AL Headford (Durapipe S & LP, UK) ee Introduction The basic requirements for pipe Jointing are common to all pipe systems made from any material (including traditional materials), whether they be for sealed pressure usage or non-pressure usage. These are a) minimal...
Author(s) : Beech 1998 Gothenburg
Pressure pipeline systems are a critical application for materials and demand high levels of performance and reliability. It is not by chance that plastics pipeline systems have gained a considerable market share, particularly in the gas and water utilities supply system. This paper briefly reviews the key properties...
Author(s) : Bar 1998 Gothenburg
Cross-linked PE (PEX) pipes have been known for two decades. Applications like floor heating and domestic sanitary systems for cold and hot water have long become standard in many countries. Increasing proportions of the total use have been captured by PEX away from traditional materials i.e. steel or copper....
Author(s) : Nomura, Hirabayashi, Troughton 1998 Gothenburg
This paper describes an assessment of the quality of butt and branch joints in polyethylene (PE) pipes, produced using the linear vibration welding technique. Results showed that butt welds in pipes of 165 mm outside diameter(0D) could be produced within a total weld/cool time of 85 seconds, which is less than 15?'0...
Author(s) : Gill, Knapp, W.Bradley, L.Bradley 1998 Gothenburg
The objectives of this research are to better understand the degradation of cross-linked polyethylene (PEX) tubing subjected to pressurized, hot chlorinated water in flow-through systems (like home plumbing) and to estimate its service lifetime. PEX tubing was subjected to pressure testing with flowing hot,...
Author(s) : Lu, Burn 1998 Gothenburg
One of the characteristic behaviours of plastics (or viscoelastics) materials is the creep phenomenon, which is defined as the continuing deformation under a constant load with time. Although research on creep of plastics pipes has been widely carried out in other plastics, little work has been reported for creep in...
Author(s) : Yoshii 1998 Gothenburg
Electro-fusion (EF) fittings are used in the joining of polyethylene (PE) gas pipes. However, the cost of fittings for large-diameter pipes is high compared with that for small-diameter pipes. Accordingly, the multilayer molding method was developed, with the aim of reducing the cost of EF fitting for large-diameter...
Author(s) : Abbas 1998 Gothenburg
Some years ago the polyolefin research and development was quite predictable and had to some extent the characteristics of a mature business. Today, it is one of the most interesting - and dynamic areas in the whole plastics industry. The reason for the excitement is mainly based on the development of new...
Author(s) : Schwarwachter 1998 Gothenburg
Plastic Pipes have been successful now for over 60 years. The first pipes with solid wall designs were used for pressure applications. Example: In the city of Berlin, the buried drinking water PVC pipes installed in private housing areas during 1935 are still in use. Test methods and Standards in the early years were...
Author(s) : Migchelsen 1998 Gothenburg
Polva Pipelife B.V., Holland, is a producer of plastic pipe systems. The company belongs to the Pipelife Group. The headoffice of the Group is in Vienna, Austria. In 1996 Polva Pipelife introduced a new product on the market with the name NO DIG DRAIN@ Recently the system has been granted a patent. NO DIG DRAIN@ is a...
Author(s) : Striplin 1998 Gothenburg
The Gas Research Institute and McElroy Manufacturing, Inc. cofunded Project 5091-271-2341 to increase the capability of the UltraMc” Computerized Ultrasonic Inspection System. This project added the 2” Iron Pipe Size (IPS), 3” IPS, 6” IPS, 8” IPS, 10” IPS, 12”, IPS, 50 mm Japan Industrial Size (JIS), 75 mm JIS, 100...
Author(s) : Wijeyesekera, Warnakulasuriya 1998 Gothenburg
Gurnble (1983) and Molin (1981) used numerical analysis to demonstrate the significance of lateral earth loading on flexible pipe design. The restraint provided by the stiffness of the side fills on the pipe influences the shape of the deformed pipe. Low trench width to pipe diameter ratios can hinder the process of...
Author(s) : Huusko, Bos 1998 Gothenburg
The main requirements for successful pipeline renovation systems are to combine an easy and safe installation with a long lifetime and a good cost performance. This paper reviews the development and evaluation of the Omega-Liner™ relining system which is a close-fit system based on a PVC alloy. Practical experiences...
Author(s) : Whittle, Burford) 1998 Gothenburg
Modified PVC pipes are being introduced for water reticulation where their tough, predictable behaviour offers advantages in both performance and material utilisation. CPE is one of the modifiers used, either alone or in combination with other additives. The effects of changes in processing conditions on both the...
Author(s) : Hopfmann, Wehner, Stoffelsma, Ryningen, Clucas, Pfaender 1998 Gothenburg
Today's success of PVC as the second largest single polymer with numerous applications would not have been possible without the development of efficient additives at the same time. In fact PVC cannot be processed in a proper way without addition of lubricants and stabilizers. This fact was already realized at the...
Author(s) : Bergman 1998 Gothenburg
Polyethylene has now been successfully used as a pipe material for around 50 years. During this time, knowledge has been gained of the three main factors that influence the lifetime of the pipe system; material factors, environmental factors and loading factors, fig. 1. It is quite clear that today's PE pipe systems...
Author(s) : Hill 1998 Gothenburg
Polyethylene has many virtues as a material for underground potable water hstribution pipes. Unlike ferrous metals, it is totally immune to corrosion, and is extremely resistant to chemical attack from any aqueous media. However it has one minor weakness - it is slightly permeable to hydrocarbons, and other organic...
Author(s) : LeRoux, Espersen 1998 Gothenburg
PElOO First introduced only 10 years ago, PElOO started to grow on the market really from the Midnineties . At the present growth rate the world-wide requirement for PE100 should reach 250 000 todyear by the turn of the century . The main market is still of course Europe but the penetration is increasing rapidly in...
Author(s) : Suys 1998 Gothenburg
Over the last two decades substantial development in Polyethylene (PE) pipe resins took place, but it was in the last five years that this range of PE-resins has been broadened with materials having a new design of molecular structure. A number of these resins are now in the market and are known as bimodal PE, with...
Author(s) : Nishimura, Macba, Ishikawa, Ueda 1998 Gothenburg
In the Great Hanshin-Awaji Earthquake, dthough leak and cracking occurred mainly in joints of small-diameter steel pipes with screwed joints, no damage occurred to polyethylene pipes. To secure aseis~uicresistance of gas pipeline, polyethylene pipes are expected to come into wider use i n the future. To deternune the...
Author(s) : Shepherd 1998 Gothenburg
This presentation is written from the perspective of the water industry and is therefore mostly concerned with pressure pipes for potable water as this is far and away the biggest area of use of plastic pipe systems. The Water Industry has been constructing its pipe network for over 150 years and it has been...
Author(s) : Van t Veer 1998 Gothenburg
I have been asked to present you with an outline of the environmental aspects of plastic pipe systems today, but I intend to take the issue a little bit broader and talk about Health, Safety and Environment aspects. I will not present a facts & figures story on technical details, but I will try to give you a broader...
Author(s) : Bresser, Palmloef 1998 Gothenburg
Over the past 15 years. plastics such as PE-X. PP. C-PVC. PB and PVDF have established their position also for hot water applications like industrial and domestic floor heating. drinking water installations. industrial piping and district heating. For example, roughly 8 % of all polyolefin pipe raw material in Europe...
Author(s) : Denning 1998 Gothenburg
This paper attempts to look at the history of Plastics Pipe system markets in Europe, to explain some of the reasons behind today's market structure and to look to the future. Estimates of the Total European market for plastic pipes for 1996 give figures in the region of 2,200,000 tonnes with the market being...
Author(s) : LeHunt 1998 Gothenburg
A comprehensive package of training programs for plastics pipeline systems has been developed for designers, installers, and operators in water supply, irrigation. gas, and drainage applications. These programs have been operational in Australia, and New Zealand over the last 4 years period, and are applied to PE,...
Author(s) : Stokes, Edwards 1998 Gothenburg
The paper examines the business and regulatory background to the infrastructure investments anticipated in the next few years, from the point of view of a major UK Water Company. Past performance of the use of plastic pipes for sewers and water mains are examined. Shortcomings of the products are identified and...
Author(s) : Bresser, Hoejer, Palmloef 1998 Gothenburg
This paper gives an overview of the different plastic systems and the spectrum of application areas. The present situation and trends for the future are described for the system design and installation, the applied standardisation, the approvals by authorities and the market size. It is attempted to give a complete...
Author(s) : Lind 1998 Gothenburg
Polypropylene has, in Europe, during the last decades gradually gained a stronger position as pipe material for non pressure sewerage applications. First heterophasic PP copolymers came into use in indoor sewerage systems, e.g. in Germany and in Scandinavia. Later Structured Wall Piping systems were developed for...
Author(s) : Davis, Greenshields, Dabas, Leevers 1998 Gothenburg
The study of Rapid Crack Propagation (RCP) in pressurised pipelines is of particular importancr to th? g a industry, where the possibility of such a failure must he minimised. Polyethylene (PE) currently dominates the market for plastic gas pipelines, and as the demands for larger diameters .and higher operating...
Author(s) : Ansell, Lawrence 1998 Gothenburg
Recent years have seen the steadily increasing use of thermoplastics for pipes and fittings for domestic hot and cold water supply and heating installations. Plastic pipe systems, in particular those that incorporate a push-in design offer considerable advantages over conventional pipe systems. However, manufacturers...
Author(s) : Holloway 1998 Gothenburg
An extrusion process for manufacturing a molecularly oriented PVC pipe is described. The pipe is stretched in both the hoop and axial d i i i o n s and is therefore described as a BiAxial PVC pipe. It is shown how this process enhances strength and toughness which allows a higher standard of pipe at lower cost. The...
Author(s) : Leevers 1998 Gothenburg
The international standardisation of tests for Rapid Crack Propagation (RCP) is approaching completion, and requirements for product and systems standards x e well established. Yet some basic issues about RCP remain contentious. In contrast to slow crack growth, there is a near-absence of service failure data, and in...
Author(s) : Hazra, Leevers 1998 Gothenburg
In previous work on the impact behaviour of pipe grade polyethylene (PE), the 'thermal decohesion model' was proposed by Leevers [ l ] to explain the embrittlement of PE under impact and at low temperatures. One of the initial assumptions of the model was that the crack tip craze could be represented by a Dugdale...
Author(s) : Francombe, Sharpe 1998 Gothenburg
Pera Technology is an independent research and development organisation, with a staff of approximately 150 dedicated to development, consultancy and technology transfer. About half of our development work is undertaken for individual clients, and we also have extensive experience in large collaborative projects. Our...
Author(s) : Higuchi, Nishimura, Tamamura, Harada 1998 Gothenburg
To estimate the long-term performance of polyethylene pipe, molecular structure of polyethylene resin were analyzed and the long-term performance test were done. By linking the molecular structure of the resin to the results of long-term performance tests such as tensile creep tests and tensile fatigue tests, it...
Author(s) : Nezbedova, Salajka, Kucera 1998 Gothenburg
Structural and morphological parameters together with processing conditions determine the type of fracture behaviour of polyethylenes. Long time brittle failure which occurs under low stresses and at room temperature limits the lifetime of polyethylens used as pipes for water and gas distribution. In order to...
Author(s) : Ifwarson, Andersson 1998 Gothenburg
This paper presents experimental data for PEX, PEM, PP and PVC pipes exposed to different chemicals. More than 150 plastic pipes of PEX, PEM, PP and PVC have been pressure tested with different chemicals. The chemicals used are; 97% Sulfuric acid, 100% Acetic acid, 30% Sodium hydroxide and a solution of 50%...
Author(s) : Ifwarson, Aoyama 1998 Gothenburg
This paper presents experimental data for three Japanese polyolefin pipe grades exposed to chlorinated water. The chlorine concentrations used are 0.5, 1 and 3 ppm. Results are presented in creep rupture diagrams. The results are compared with hydrostatic pressure tests using 0 ppm of chlorine. Extrapolations using...
Author(s) : Leijstrom, Ifwarson 1998 Gothenburg
This paper presents experimental evidences and experiences obta~nedfrom the use of the so-called Miner's rule for determination of lifetime expectancies of plastic pipes subjected to varying testing conditions, i.e. altering temperatures and pressures. Results obtained from some unique long-term pressure tests of PE,...
Author(s) : Morris, Cant 1998 Gothenburg
In the UK, jetting of drains and sewers is undertaken mainly for emergency clearance of blockages, rather than planned cleaning as in some other countries. Jetting equipment has been constantly upgraded to produce higher pressures in order to provide a quicker service to customers and better return on...
Author(s) : Buckler 1998 Gothenburg
It has long been recognised that the achilles heel of a thermoplastics pipe system 1s the quality of the site jointing procedure. Successful site welding, and indeed the making of mechanical joints, requires a higher level of competence than the more conventional jointing methods associated with traditional...
Author(s) : Muckle, Wood, Reed 1998 Gothenburg
Developed to address the practical problems experienced on site with the preparation of the surface of polyethylene (PE) pipes for electrofusion jointing, skinned PE pipe also offers the secondary benefit of general pipe protection against gouging and other forms of abrasion damage. This paper discilsses the concept...
Author(s) : Clutton, Rose, Capaccio 1998 Gothenburg
The development of pipe grades requires the careful balance of several mechanical properties, of which two of the most important are the resistance to slow crack growth (SCG) and rapid crack propagation (RCP). In this paper, we present small-scale tests which enable the rapid assessment of these properties. These...
Author(s) : Beech 1998 Gothenburg
Pressure pipeline systems are a critical application for materials and demand high levels of performance and reliability. Resistance to slow crack growth is a key consideration for both metals and polymers alike, which must be dealt with by the appropriate material selection, product design and manufacturing control....
Author(s) : Traenkner 1998 Gothenburg
This paper presents the results of a series of notch tests on bars and pipes. Tests were performed on PE, PEX (peroxide, silane and radiation), PP and PB resins. The temperature was 80°C. Large differences were observed between the various polyolefin grades. Differences were also observed between different PEX-grades...
Author(s) : Marshall, Morley, Pearson 1998 Gothenburg
The Water Industry in England and Wales has responsibility for an approximate length of 300,000km of water main, ~nuchof which was laid over 70 years ago using cast iron. Subsequently, asbestos cement, PVCu and cement lined ductile iron have been used. The old iron pipe systems that were installed in many of the...
Author(s) : Jones 1998 Gothenburg
In this paper the author reviews the current situation with regard to the development of standards for plastics piping systems. There are many detailed documents relating to the timetable/work programme of IS0 /CEN standards. If you do not have access to them the author will be pleased to answer specific points. The...
Author(s) : Vanspeybroeck 1998 Gothenburg
Plastics pipes and fittings are used in all types of applications in the water, gas, sewer and other industrial applications, where long life (minimum 50 years) is needed. Early applications have already been reported since the year 1935, but the imp0rtar.t growth was after the years 1970. A steady stream of new...
Author(s) : Boot, Naqvi 1998 Gothenburg
The principles underlying the concept of thermoplastically lined pipes for untreated well-head fluids, with particular reference to subsea applications, are first described. The prime sources of load on the lining are then identified as build-up of gas pressure in the pipe-lining annulus and swell of the lining. Since...
Author(s) : Wright, Burley 1998 Gothenburg
Advanced Engineering Solutions Limited (AES) and Colin Burley Associates have jointly developed and patented a Silane cross-linked polyethylene liner for the internal lining of pipelines, known as the (SPEX ) liner. For a number of years Medium Density Polyethylene (MDPE) pipe has been extensively used as a liner to...
Author(s) : Alferink, Bjoerklund, Kallioinen 1998 Gothenburg
Over the last 15 years several attempts have been undertaken to establish a design method for plastics pipes (IS0 TC138 WG13) and over the last ten years to establish an unified design method for all buried pipes (CEN TC1641165 JWGI). Several national methods are available and it is shown over the last ten years that...
Author(s) : Honda 1998 Gothenburg
In the Japan Water industry, there has been a strong movement recently to use PE piping . Till quite recently, PVC and ironjprimarily ductile iron) have been used for water piping in Japan generally. The movement toward PE for water piping was pushed by The Great Hanshin-Awaji(Kobe) Earthquake occurred in 1995. By...
Author(s) : Allan, Hashemi, Faulkner, Bevis 1998 Gothenburg
A novel moulding process has been developed at the Wolfson Centre for Materials Processing, Bmnel University, for the production of curvilinear forms of thermoplastic materials. The process has been used with a gas pipe grade of medium density polyethylene to manufacture right-angled elbows of 63mm diameter SDR 11...
Author(s) : Abdel, Vanspeybroeck 1998 Gothenburg
After a water supply crisis due to the age of the distribution system and insufficient sources of water, the Municipal Water Supply Co~npanyof Palermo (A.M.A.P.) decided in 1990 to proceed to the acquisition of a new "Preliminary Project of the water supply for the town of Palermo". Four engineers (Cesare Arici,...
Author(s) : Boot, Javadi 1998 Gothenburg
The fundamental structural characteristics of cured-in-place pipe for sewer linings are first described, and current procedure for their design reviewed. Following identification of the major inconsistencies in this design philosophy, a programme of research with the objective of addressing these issues is summarised....
Author(s) : Ebner, Konrad 1998 Gothenburg
Pipes made .from plastics are widespreadly used for numerous applications, and pipes made from polypropylene (PP) play a major role in manv of these fields, but especially in sectors such as pressurised industrial piping, domestic hot and cold water distribution and soil & waste discharge systems. Polypropylene block...
Author(s) : Bonn 1998 Gothenburg
This paper relates experience gained using Thermopipe. a Thin Walled Polyester Reinforced Polyethylene (PRP) pipe for the rehabilitation of water mains. Some 46km have now been installed world wide, with the bulk of the work carried out in the UK, where 12 water companies have used the system. The Paper also...
Author(s) : Bradley, Slay, Self, Register, Lamborn 1998 Gothenburg
The crack growth rate in HMN 5202 and HXM 50100 polyethylcne has bcen studied as a function of stress intensity using deeply notched three-point bend specimens. l'he load-line displacen~entin response to a static applied load has been measured, with tlie material compliance as a function of time determined from the...
Author(s) : Thornhill, Curley, Gilchrist 1998 Gothenburg
The use of glass fibre reinforced epoxy pipelines in the high pressure transport of fluids is becoming more widespread; this is due to the high strength to weight ratio and the corrosion resistant properties of these material systems. A 12-inch internal diameter glass fibre reinforced epoxy pipeline with winding...
Author(s) : Horst, Weyn, Hermkens 1998 Gothenburg
For a long time the energy distribution companies in the Netherlands have expressed their need for ways of effectively assessing the quality of field-installed PE-pipe systems to prove integrity and reduce maintenance and repair costs. This becomes especially important with the increased use of these PE-systems for...
Author(s) : Smith, Guzowski 1998 Gothenburg
Some forty years ago simple 0 ring joints for PVCu pipes were just being introduced as an alternative to solvent cemented joints. Rubber lip seal type of joints soon followed for both pressure and non pressure applications. Whilst in theory these designs were fine, both styles of joint had operational problems,...
Author(s) : Jones 1998 Gothenburg
The activities relevant to this paper are being undertaken in the context of a COST Cooperation. COST is the acronym for the French equivalent of "European Cooperation in the Field of Scientific and Technical Research" (Cooperation européenne dans le domain de la recherche scientifique et technique). COST Cooperation...
Author(s) : Scholten, Wolters 1998 Gothenburg
An investigation has been carried out into butt welding and electrofusion welding of PEX pipes, which had been crosslinked using the peroxide, silane and electron beam processes (PEXa, PEXb and PEXc respectively). A new hypothesis was set-up to explain the good weld quality of PEXa pipes electrowelded with regular...
Author(s) : Howell 1998 Gothenburg
This paper examines the asset investment options available to Water Utility Companies for the maintenance of underground utilities emphasising the advantages in taking the best whole life cost option for rehabilitation or replacement. Design, technical. operational and unit cost comparisons are then presented for the...
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