Author(s) : THOMAS W DAVIES 2001 Munich
The discussion concerns e-business and if it applies to manufacturers of plastic pipes. In a business world companies objectives are predominantly centred around three areas, retaining customers, improving efficiencies and expanding markets. Plastic pipe manufacturers are no exception and the benefits of e-business...
Author(s) : Paschal, Ciechanowski 2001 Munich
Fittings used in water and gas piping systems are rarely, if ever, explicitly rated for load carrying capability relative to internal pressure. In some cases the material or resin used to manufacture the fitting is stress-rated to a period of 100,000 hours (PPI TR3) or 50 years (ISO TR 9080 and FDIS 9080). This...
Author(s) : Scholten, Gueugnaut, Berthier 2001 Munich
Detergents of the type nonylphenol ethoxylate (NPE) are often used in PE pipe tests at 80°C like the Full Notch Creep Test, Cone test and Constant Load test. However, evidence is presented that this class of detergents is very vulnerable to oxidation by oxygen from the air surrounding the tests baths. This leads to a...
Author(s) : Tjandraatmadia, Burn 2001 Munich
To increase understanding of chemical jointing in pipes, the strength of solvent cement joints in acrylonitrile-butadiene-styrene (ABS) and poly(vinyl chloride) (PVC) pipes was investigated, using mechanical tests and morphology studies. The strength of solvent cement increases with curing time, and it was found that...
Author(s) : Edwards, Broutman, Choi 2001 Munich
The Alternate Methods Committee of the Plastics Pipe Institute’s Hydrostatic Stress Board (HSB) has completed development of an alternate method for determining the hydrostatic design basis (HDB) for plastic piping materials. The initial work was reported at Plastic Pipes X, in Sweden in 1998.1 An ASTM test method...
Author(s) : Lang, Pinter, Stern 2001 Munich
Engineering polymers, in particular special grades of poly(ethylene) (PE), are gaining importance in many pipe applications with targeted service lives of several decades. To ensure proper performance of such pipes over the required lifetime, polymer physics and mechanics concepts are needed which adequately account...
Author(s) : Brunecker 2001 Munich
The use of the no-dig method of renovating waste water sewer pipes is becoming steadily more common in the area of sewer systems, in spite of ever declining budgets. But maybe for this very same reason, other contemporary terms such as “pipeline integrity” are also becoming more important. Against this background,...
Author(s) : Vibien, Couch, Oliphant, Zhou, Zhang, Chudnovsky 2001 Munich
The chlorine present in potable water as a disinfectant has been reported to reduce the lifetime of some plumbing system components. In this study the nature of the failure mechanism of a commercial cross-linked polyethylene (PEX) pipe material exposed in the laboratory to chlorinated potable water is examined. The...
Author(s) : Whittle,Burford, Hoffmann 2001 Munich
A series of modified PVC pipes, with different concentrations of chlorinated polyethylene, were manufactured under carefully controlled processing conditions. The strength and toughness of each pipe was measured by a variety of methods including uniaxial tensile strength, notched C-ring, essential work of fracture,...
Author(s) : Hill, Wilson, Headford 2001 Munich
Butt fusion welding is the most reliable and unobtrusive method of joining PE pipes (and spigot fittings) of virtually any size-except perhaps the smallest where other methods are usually preferred. It is the dominant method of jointing both medium and large pipe sizes, but for different reasons. In medium pipe sizes...
Author(s) : Fairfield, Reid, Hounsome, Edwards, Sibbald 2001 Munich
This paper provides estimates of the draw force needed to pull sub-ducts or cables through a series of typical ducted utility networks. Variables such as : coefficient of friction between the outside of the cable and inside of the duct, the main duct’s vertical diameter, the cable bundle or sub-duct’s external...
Author(s) : Glanert 2001 Munich
Fold and form procedures for the trenchless renovation of gravity drainage pipe systems have been used throughout the world since the late eighties. Fold and form procedures are classified as renovation by the European Committee for Standardization CEN. OmegaLiner®, a product combining the advantages of comparable...
Author(s) : Choi, Lee, Broutman, Edwards, Palermo, Cho, Choi, Park 2001 Munich
In recently designated plane strain grooved tensile (PSGT) methodology of ASTM F2018 standard, a groove in the direction perpendicular to the loading axis allows biaxial stress state to be generated under a uniaxial loading. The biaxial stress state produced very closely approximates the internally pressurized pipes...
Author(s) : Laurent 2001 Munich
The development of improved toughness properties of PE pipe resins agrees with the implementation of modern PE pipe installation technologies. Especially the increased resistance to Stress Cracking and to Slow Crack Growth allows contemplation of improved economics, longer lifetime and higher safety. However the...
Author(s) : Balika, Lang 2001 Munich
The creep crack growth (CCG) and the fatigue crack growth (FCG) behaviour of a commercial pipe grade PVC material was studied based on a linear elastic fracture mechanics (LEFM) methodology. The FCG tests were performed under sinusoidal load control at a frequency of 5 Hz and at R-ratios (Fmin/Fmax) of 0.1, 0.3 and...
Author(s) : Jarnecke, Mamoun 2001 Munich
Magnetic detectable polyethylene (PE) pipe has been developed for the gas distribution system that has permanent detection for locating underground piping. Magnetic detectable PE pipe differs from normal PE pipe by the addition of magnetic particles in the PE resin, which are magnetized in a sinusoidal pattern during...
Author(s) : Sudheer, Pimputkar, Michael, Mamoun 2001 Munich
A new plastic piping material to augment and complement polyethylene (PE) (and newer materials such as Polyamide 11 and cross-linked PE) and extend the use of plastics to highpressure distribution piping is being developed. The scope of work consists of identification and laboratory testing of candidate materials, and...
Author(s) : Sun, Niu, J.Sun 2001 Munich
Steel mesh reinforced plastic composite pipe, possessing advantages of both metal and plastics, is a new type pipe that made a perfect combination of steel wire mesh and thermoplastics. A general description of characteristics of pipe structure, production process, pipe performance analysis and model projects of...
Author(s) : Wroblewska, Kwietniewski, Roszkowski 2001 Munich
The condition of underground infrastructure in Poland at the beginning of the 1990s was very poor. The length of the water supply, sewage and gas network was relatively small, compared with Western Europe, and the installation materials used at the times of socialism were of very low quality; the same can be said...
Author(s) : Morgan, Hill 2001 Munich
Transco, part of the Lattice Group, is the largest Public Gas Transporter in Great Britain. It currently operates a Distribution system of some 250,000 kilometers. Developments in polyethylene pipe technology have led to an ongoing increase in the size of pipe being laid in the U.K. Currently, pipes up to 630 mm...
Author(s) : Jivraj, Sehanobish, Dun, Damen, Wu, Zhou, Chen, Shulkin, Chudnovsky 2001 Munich
Analysis of polyethylene (PE) pipes ductile failure (ballooning) suggests that it is directly related to the delayed necking phenomena and time to ductile failure of PE pipe can be evaluated as the time to delayed necking. The necking in polyethylene (PE) is studied under displacement control (ramp test) and load...
Author(s) : Papp, Steve, Amos, Briers 2001 Munich
Fluoropolymer based polymer processing additives (PPAs) are frequently used in the polyethylene industry. Besides their ability to eliminate melt fracture and die build-up, PPAs are used to optimise the process conditions in a wide range of applications without having to make compromises on the properties of the final...
Author(s) : Campbell, Reyes, Rush, James 2001 Munich
This paper summarizes work that was undertaken to improve coiled pipe operations. Two different technical issues were addressed. The first is to improve the reliability and lower cost of gas mains by understanding the effects of excess ovality in plastic gas pipe. The second is to improve the handling of plastic pipe...
Author(s) : Jones 2001 Munich
This paper provides an overview of the evolving Liberalisation process in the context of the European Water sector. The underlying drivers are outlined from the perspective of EU member countries, the EU Commission and the broader international situation. The importance of the Liberalisation process in the balance of...
Author(s) : Sadler, Burn, Whittle 2001 Munich
Root intrusion into sewer pipelines is a major concern, especially in areas with a combination of dry climate and vigorous vegetation growth. For elastomeric pipe joints to resist root intrusion, some national standards specify a minimum interfacial pressure that must be maintained between the elastomeric ring and the...
Author(s) : Nishimura, Inoue, Inoue, Tani, Higuchi 2001 Munich
Electrofusion (EF) joints have been widely used as easy-to-fuse and high-quality joints for joining polyethylene (PE) pipes. When we introduced EF joints 150 mm or more in diameter, an electrofusion simulation program was concurrently developed to reduce time for design and experimental works. It was verified that the...
Author(s) : Scheelen, Tauber, Berndtson, Lackner, Bertrand, Bilda 2001 Munich
Founded on February 24, 1999, the PE100+ Association is an industry organisation of several polyethylene (PE) manufacturers whose objective is to guarantee consistent quality at the highest level in the production and use of PE 100 pipe material. The authors describe the current situation in terms of European...
Author(s) : Wuest 2001 Munich
This paper is about the squeeze-off tests on pipes made of PE 80, PE 100 and PE-Xa of different dimensions. After having squeezed off the pipes to a rate of 0.8 the air and water impermeability of the squeezed point is examined at different pressures and the leakage rates are determined. After reforming the pipe...
Author(s) : Crunkhorn, Smith, Whiter, Mulheron 2001 Munich
Cast iron pipes have been loaded to failure using a four point bending geometry under displacement-controlled loading. Specimens were tested with various liner configurations : unlined, epoxy resin lined or lined with one of two interactive (semi-structural) liners. Some of the pipes also had a circumferential notch...
Author(s) : Ivankovic, Tropsa, Jasak, Leevers 2001 Munich
This work presents a 3D coupled solid-fluid model for predicting fast failures in pressurised plastic pipes. It is developed within a unified computational procedure where both solid pipe and pressurising media are discretised using the Finite Volume method. The coupling is achieved across the pipe-fluid interface...
Author(s) : Petry, Gressmann, Pylarski 2001 Munich
Electrofusion is undoubtedly the most important method for jointing polyethylene piping systems in gas and water distribution. Today it is not unusual to joint PE 100 pipes and fittings in diameters up to 500 mm using electrofusion couplers whereas only five years ago the maximum size used was 315 mm. With these...
Author(s) : Kovriga, Gorilovsky 2001 Munich
According to the Russian standard local high pressure gas lines have pressure level of 6 and 12 bar. To provide these gas lines by PE pipes researches were conducted and pipes made from PE100 diameter 160 mm SDR7.4 were developed and produced. Pipe’s laying (850 m) was made in Vladimir region in 1998. In 2000 pipes...
Author(s) : Synnerholm 2001 Munich
PE 100 pipes were introduced as a possibility for use for natural gas in Sweden and Norway. The authorities had no doubts that the pipes were suitable for what they were designed. The main issue was whether the pipes were suitable for the same proximity distances or if they had to be altered. This paper explains the...
Author(s) : Neumayer, Knauder, Pilz, Lang, Major 2001 Munich
The importance of plastics piping systems based on glass fibre reinforced unsaturated polyester resins (GRP-UP) for water supply, industrial or sewer pipe works has continuously increased worldwide. Centrifugal casting (CC) is one of the most important technologies to manufacture CC-GRP-UP pipes. UP-resins, mineral...
Author(s) : Harris 2001 Munich
This paper discusses the important role that technology continues to play in addressing the challenges faced by the energy industry and the natural gas industry in particular. It also highlights how the changing structure of the industry is having an impact on the way technology development needs are being met. The...
Author(s) : Werner 2001 Munich
This presentation illustrates the extended functional possibilities yielded by multilayer systems based on simple polyethylene pipes installed underground. A simple, installed polyethylene pipe comprises: • A core, through which the medium to be transported flows, • A pipe wall made of polyethylene, which is equipped...
Author(s) : Friend, Harget, Hauki 2001 Munich
Fusion jointing of cross-linked polyethylene (PE-X) pipe systems can be achieved by the use of conventional electrofusion (EF) couplers. The body of these couplers are manufactured from thermoplastic polyethylene, hence the performance of the joint is limited by the response of the body of the EF coupler. We report on...
Author(s) : Oertli, Ifwarson 2001 Munich
While guaranteed lifetimes of pressure pipes in use is roughly 50 years, it is commonly accepted that a well designed and manufactured HDPE/MDPE pressure pipe would last as long as 100 years without failures. With ever-growing world population and intensifying pollution, it has become increasingly difficult supplying...
Author(s) : Lorbeer 2001 Munich
The most important requirement for a pipe in H & C water applications is that it remains trouble free throughout its life time. The life span of a piping system is influenced by the fluid conveyed through it; the external environment of the pipe (sunlight, grease, etc.); and the pipes operating-conditions...
Author(s) : Davis, Burn, Whittle 2001 Munich
The C-ring test method is widely used by the water industry to determine the fracture toughness of poly(vinyl chloride) (PVC) pipes. The test currently forms a draft ISO standard (ISO/DIS 11673.2) and an interim Australian/New Zealand Standard (AS/NZS 1462.19(Int)) for fracture toughness assessment. Whilst results...
Author(s) : Eckert 2001 Munich
Crosslinked polyethylene (PE-X) pipes, successfully used for decades in house installations and heating systems, have found a new and growing application in buried gas and water supply systems, in recent years. The reason for the renewed success of PE-X is due to its unsurpassed resistance to notches. The use of sand...
Author(s) : Ebner 2001 Munich
Polypropylene (PP) has a long and successful tradition as a material for piping applications. Polypropylene can be modified in many ways to tailor it for the needs of specific applications and markets. Typical examples are sanitary pressure piping systems made from PP random co-polymers (PP-R) for domestic hot and...
Author(s) : Stahmner, Whittle 2001 Munich
A number of PVC pressure pipes were exhumed from a large rural water supply scheme constructed in the early 1970s. The pipes had been extruded by three manufacturers in both elastomeric seal and solvent cement joints. The pipes were subjected to a range of mechanical tests in order to assess whether there had been any...
Author(s) : Scharwaechter 2001 Munich
Design of new rubber seal joints during last years have focused more on reduction of jointing forces than of sealing forces. Which sealing quality is necessary to avoid capillary water transfer and leakage through the joints on short and long-term, is an open question. Based on existing publications and test results...
Author(s) : Lenz 2001 Munich
The quality of the PE products used for gas and water pipe line systems was constantly improved in the last decades. The renouncement of the complex sand embedding of buried pipes and thus the use of PE pipes in no-dig procedures cannot be impossible any more. However the pipes have to be tested on the effects caused...
Author(s) : Stokes, Potter, Muhl, Acland 2001 Munich
Research indicates that the scoring of polyethylene pipes that can occur during directional drilling operations in clay soils will not exceed the specification of 10% pipe wall scoring depth. However, a higher level of damage may occur in different types of soils from these operations. Further investigations from...
Author(s) : Beech, Ferguson, Clutton 2001 Munich
Design of pipe systems for 50 year lifetimes depends on accelerated testing of pipe at different temperatures and standard extrapolation methods for assessment of whether the minimum required strength is achieved. Further acceleration is used in the notched pipe test (NPT), which is a medium term (up to 1000 hour)...
Author(s) : Braegelmann 2001 Munich
The only pipe materials for gas installations inside buildings in Germany and most of Europe used to be metals for a long period of time. Especially screwed steel pipes and soldered copper pipes have been installed. During the last few years also press systems made of copper were established. In contrast to this...
Author(s) : Berthold, Boehm, Enderle, Lackner, Lilge, Schulte 2001 Munich
The new generation pipe materials PE 100 are now well positioned in the market because of their unusual combination of mechanical properties. Major advantages are high resistance versus slow crack growth combined with superior stiffness. These new PE 100 resins show very high long term hydrostatic strength for...
Author(s) : Backman 2001 Munich
The introduction of bimodal polyethylene materials for piping systems such as PE100 and third generation PE80 HD has reinforced the trend from traditional to PE materials in piping systems for drinking water and gas applications. Improved physical properties and cost effective piping systems have increased the...
Author(s) : Keller 2001 Munich
Palermo, the capital of Sicily, is full of history and character - but in summer months it is often without water. At present, Palermo is currently implementing the biggest project of its kind in the field of European water distribution (Figures 1, 2 and 3). The population of Palermo is growing constantly. The water...
Author(s) : Oesterholt, Scholten, Roebers 2001 Munich
Worldwide more and more buildings are connected to natural gas. Until recently the gas within the building was exclusively distributed through metal pipe systems, such as straight copper pipes, soldered together and straight steel pipes, screwed together. About six years ago some pilot projects with PEX (crosslinked...
Author(s) : Ettinger 2001 Munich
Polyolefins have been used in chemical and industrial applications for many years with an impressive and highly successful track record. However, the progress of polyolefin systems in substituting traditional materials such as cast iron, steel, concrete and clay has been much more striking in construction and utility...
Author(s) : Fairfield, Hounsome, Reid 2001 Munich
This paper presents a method of optimising the distribution of plastic in a twin-walled, corrugated duct. This could be used to achieve maximum stiffness for minimum linear mass or a desired target stiffness for any envisaged market for the product. Spreadsheet optimisation routines1 based on a generalised reduced...
Author(s) : Stokes, Potter, Metcalfe, Bowman, Graham 2001 Munich
The response of three different forms of polyvinyl chloride (PVC) pipe has been explored when the pipes had attached to them ferrule straps. Pipes were subjected to fluctuating internal pressure (fatigue) loading at 20°C, and the lifetimes, location of any failures and the types of failures recorded. Tests were made...
Author(s) : Beech, Ducan, Millar 2001 Munich
Polyethylene has been used for pipeline applications for nearly 50 years now. It has become the prime material choice for gas and water distribution systems and many other applications worldwide. This paper reviews the growth in the market for polyethylene pipe products for both pressure and non pressure applications...
Author(s) : Frank 2001 Munich
Due to an increased environmental awareness, also in the field of sewerage, the problems with leaking drains have been given special emphasis. As sewage systems and treatment plants are often converted from mixed wastewater to concentrated, highly polluted water, leakproof pipelines are urgently needed...
Author(s) : Damen, Schramm, Quack, Sehanobish, Cham 2001 Munich
Developments in catalyst and process technology have resulted in a new highly differentiated product family based on ethylene-α-olefin copolymers. This paper reports on the key attributes of these materials. These polymers show superior Long Term Hydrostatic Strength at higher temperatures, without the need for...
Author(s) : Palmloef, Haizmann 2001 Munich
In practice the career of peroxide cross-linked polyethylene started in 1972 with the underfloor heating of the sports arena in Munich as a snow and ice melting system, built for the Olympic games. Since then the propagation of PE-X has been unstoppable. The spread of applications followed with tap water pipes and...
Author(s) : Alferink 2001 Munich
When starting with the application of buried thermoplastics pipes in the fifties, Wavin started to gain a lot of experimental experience with these pipes, which later formed a solid base for the correct application of thermoplastics pipes. In analogy, a lot of experimental experience is gained now with buried manholes...
Author(s) : Tarbet, Smoker 2001 Munich
There is continuing pressure within the U.K. for water companies to reduce costs whilst increasing levels of service to customers. Staff numbers within the water companies have been reduced leading to less site supervision by water company engineers and the letting of design and build contracts. The design and...
Author(s) : Schulte 2001 Munich
Lifetime expectations play a major role when selecting materials for pressure pipes. Information on the service life of a piping system made of polyethylene can be gained from the creep rupture tests at various temperatures being evaluated by standardized extrapolation methods (ISO/TR 9080). With the help of test...
Author(s) : Groves, Goodrich 2001 Munich
The COREL – corrosion resisting liners – project has been running since 1997 with the aim of qualifying plastic lining systems for use in upstream oil and gas pipelines. Lined carbon steel pipes can be cheaper to install and operate than alternatives such as corrosion resistant alloys or large corrosion allowances and...
Author(s) : Richter 2001 Munich
Pipelines are the arteries of civilization. One of the greatest challenges of our age, namely the supply of clean water world-wide, cannot be resolved without plastic pipes for the efficient transport of drinking water and sewage. Of all the types of plastic suitable for this application, polyolefins are – after PVC –...
Author(s) : Rydin 2001 Munich
During the last 15 years multilayer polypropylene coating systems have been developed and used as external coating for subsea pipelines in the offshore industry. There is now an increasing interest in the offshore steel pipe coating market for deepwater fields with a depth exceeding 1000 meters. The Gulf of Mexico and...
Author(s) : Palermo 2001 Munich
In addition to the HDB (Hydrostatic Design Basis) pressure rating obtained using ASTM D 2837, PPI (Plastics Pipe Institute Inc.) now also lists the MRS (Minimum Required Strength) pressure rating obtained with ISO 9080 in PPI’s publication TR-4, “Hydrostatic Design Bases (HDB), Pressure Design Bases (PDB), Strength...
Author(s) : Ashworth 2001 Munich
This paper describes an approach for performing improved commissioning tests on gas distribution mains. It covers the background theory to the problems involved, which include the discrimination of leaks from creep and temperature change. The production of models to predict the creep behaviour is outlined, along with...
Author(s) : Bos, Tan 2001 Munich
The paper examines the production of PVC and its conversion into PVC-U pipes. Advances in chemistry, process engineering and the design of extrusion equipment have led to significant improvements in quality and consistency of both PVC polymers and pipes made from them. At the same time, pipe productivity has risen...
Author(s) : Koestering, Laurent 2001 Munich
With alternative installation techniques for drinking water pipes, the installed pipe has to take high stresses because of point loads and outside damages. The specific raw material characteristics, which have been proven by different test results, have been transferred to a pipe system, which allows cost savings with...
Author(s) : Thompson 2001 Munich
PVC in the third Millennium - this sounds fantastic! How can an old fashioned - as some people believe - plastics material continue to grow and develop further in this new and even faster emerging new millennium? PVC is under more and more competition in the pipe industry from other polymers such as PE and PP but also...
Author(s) : Vanspeybroeck 2001 Munich
Although total safety in the gas industry may be an impossible dream, each engineer must definitely use every possible means to come near to this perfection. In view of this objective some gas companies join their efforts for combined research and development in order to improve standards or specifications and...
Author(s) : Frost, Gibson 2001 Munich
This paper describes the activities of the Joint Industry Project on Implementation of Reinforced Thermoplastic Pipe in the Oil and Gas Industries. The aim of the JIP is to promote applications of this new class of product in the transport of oilfield fluids, in gas transmission and in subsea flowlines.
Author(s) : Rouyer, Cornette 2001 Munich
Insofar as installing piping systems with traditional sand embedding is quite expensive and time-consuming, there is a current trend towards cost-effective, “trenchless” installation techniques (e.g. “ploughed-in”, directional drilling). Such buried pipes may be submitted to undesired external solicitations, namely...
Author(s) : Drummond, Fairfield, Wamuziri 2001 Munich
First Order Second Moment (FOSM) analysis techniques, employed in the development of limit state design codes, allow designers to account for the variations and random nature of the material properties and load effects inherent in the design of engineered structures. A generated non-linear equation is used in...
Author(s) : Alferink 2001 Munich
Two papers dealing with the intermediate results of the TEPPFA / APME project on design of thermoplastics pipes has been published at the 10th Plastics Pipes Conference in Gothenburg in 1998 by Alferink et al.1, 2 Meanwhile the study has been almost completed and the results discussed with several experts. Pipe...
Author(s) : Olliff, Rolfe, Wijeyesekera, Reginold 2001 Munich
Soil-pipe interaction studies generally recognise the significance of deformations in the pipe due to soil loading, but not differential ground and structure movements, which can induce excessive stress concentrations in the pipeline. Plastics pipes can suffer failure due to such movements, though their flexibility...
Author(s) : Brenik 2001 Munich
Topics concerning pure or further developed materials take priority within the framework of this event. This lecture treats the combination of different materials and the possibilities of creating out of them the optimal construction for the respective, individually defined case of application. Chemical, mechanical...
Author(s) : EK 2001 Munich
The new generation PP-B (Stiff PP), first introduced in 1998 for underground drainage and sewerage, is primarily based on a combination of a unique stiffness/impact property balance, low specific weight, good long-term properties and excellent chemical resistance. This paper gives the status of what has been achieved...
Author(s) : Nezbedova, Zahradnickova, Salajka 2001 Munich
High-density polyethylene (HDPE) is being used more and more in critical long-term application, such as in pipes for the distribution of water and gas. For this reason it is important to have a strong understanding of those parameters which control the fracture behaviour of HDPE. The main parameters are : i. Chain...
Author(s) : Kraehling, Spindler 2001 Munich
Market success factors agree with sustainability indicators to a large extent, both being multi-dimensional. Complete life cycle considerations are essential for comprehensive assessments. PVC pipeline systems are shown to be competitive considering all three sustainability categories, economic, ecological, and...
Author(s) : Kuliczkowski, Kubicka 2001 Munich
In the paper the situation, which exists in Poland in the field of the design of plastic pipes is presented. The size of the plastic pipes deflection obtained from the field measurements, which took place in Poland a few years ago, is widely discussed. The variety of pipe bedding conditions as well as its technical...
Author(s) : Stafford, Bircumshaw 2001 Munich
The very high costs of underground electrical power transmission preclude its widespread usage even where social and environmental concerns make it highly desirable. This paper examines the technologies of below ground alternatives to overhead power lines and identifies the opportunities for introducing pipeline...
Author(s) : Gibson, Wu, Frost, Korsunsky 2001 Munich
This paper considers the collapse of liners confined within rigid pipes and recommends design equations top avoid this effect. Two and three-dimensional aspects of the problem are examined. The onset of unstable collapse is well-described by the critical pressure predicted from analytical models and is essentially an...
Author(s) : Leevers, Moreno, Paizis 2001 Munich
The resistance of PE pipes to rapid crack propagation depends strongly on temperature. The critical pressure measured using ISO 13477 ‘S4’ tests increases abruptly above a transition temperature Tc. For PE100 grades Tc has become a primary index of quality : it must remain below 0°C despite a tendency to increase...
Author(s) : Allcard, Beech 2001 Munich
It is widely accepted that in testing, the long term fracture mode for Electrofusion (EF) socket fittings is via Slow Crack Growth (SCG), initiating from the first wire turn from the centre cold zone of the fitting. This study examines the injection moulding process and the EF welding process and their potential to...
Author(s) : Pinter, Lang 2001 Munich
In this work the influence of three different stabiliser systems on the stress rupture behaviour of high density polyethylene (PE-HD) pipes under constant internal pressure was examined at 60 and 80 °C with special consideration of the quasi-brittle failure by growth of a single crack in the failure regime preceding...
Author(s) : Mahabir, Henderson 2001 Munich
A 24 Design of Experiments (DOE) test grid was run to examine the influence of the following variables on the chlorine resistance of PEX pipe; temperature, water quality (pH, chlorine concentration, ORP) and metal ions (inert vs. copper fittings). The four factors were each run at two levels and a centre point was...
Author(s) : Gunther, Sandstrum 2001 Munich
Washington Gas has been researching a number of innovative methods for the repair and replacement of older large diameter cast iron mains. We considered direct burial, rolldown, U Lining, PIM, and guided boring. The ideal replacement technique would allow for a fully rated (64 psi or 5 bar) system which would have a...
Author(s) : Hackwell 2001 Munich
PVC remains the dominant polymer resin for pipe production throughput Europe and will remain so over the foreseeable future. Environmental pressure and development of newer grades of competitive materials have contributed to restraining growth for PVC, nevertheless growth is seen for multilayer and corrugated pipes....
Author(s) : Elzink 2001 Munich
The type of problems encountered in existing pipelines are presented in this paper, together with the available methods to rehabilitate them. In the majority of the cases plastics are nowadays applied, either to replace the existing ones, or to renovate them by lining. The latter is increasingly gaining...
Author(s) : Meijering 2001 Munich
In the Netherlands, a gas distribution system of Ductile PVC with elastomeric sealing ring joints and several special features is already operating to full satisfaction during more than 35 years. Today, Ductile PVC is the preferred material in this market. The total length of the gas distribution net is about 110.000...
Author(s) : Burn, Davis, DeSilva, Marksjo, Tucker, Geehman 2001 Munich
To allow long-term strategies to be implemented for the replacement or refurbishment of water pipelines, a planning model called the Pipeline Asset and Risk Management System (PARMS) has been developed. This model, although based upon life cycle costing methodologies has been designed to incorporate whole of life...
Author(s) : Boon 2001 Munich
This paper considers the current state of the UK water industry with respect to its maintenance of its pipelines, in the context of the regulatory framework in the UK, over the next 4 years. It also reviews the development of a thin walled PE liner for pipes in need of rehabilitation. The benefits of the use of thin...
Author(s) : Pilz, Lang 2001 Munich
To characterize the viscoelastic properties such as creep modulus and time dependent Poissons’s ratio of commercial medium and high density polyethylene materials (PE-MD, PE-HD), in total 5 types of polyethylene (PE) (pipe grades and non-pipe grades) with densities ranging from 0.928 to 0.951 g/cm3 were investigated....
Author(s) : Troughton 2001 Munich
This paper describes the development of an ultrasonic non-destructive examination (NDE) system that is incorporated into an automatic butt fusion welding machine and performs an examination of the joint within the cooling time of the welding cycle. The programme of work included the optimisation of the ultrasonic NDE...
Author(s) : Andersson 2001 Munich
The lifetime of plastic pipes has been studied at Bodycote Polymer AB (formerly Studsvik Polymer AB) for more than 27 years. This paper presents some of the factors found to control the lifetime of plastic pipes. How to extrapolate the lifetime of plastic pipes will be presented and discussed. A question will also be...
Author(s) : Bresser 2001 Munich
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