Fundamentals
Plastic Pipes Conference Association # 1970 Southampton
Van der Vegt
The family of thermoplastics has, over the past few decades, been :I>e fastest growing group of materials, the overall growth rate of plastics production and consumption being about 15% per annum. An approximately constant fraction of the total plastics production (about 3%) is applied in pipes, in other words, the consumption of plastics pipes also grows at a rate of about 15% per annum. The present plastics pipe consumption in the UK is about 44,000 t~ns/~ear, and i t i s estimated that in the forthcoming 15 to 20 years it will grow to a saturation level of 300,000 to 400,000 tons/year, which will then cover all the plastics pipes applications that are potentially possible.
We appear to be living in the middle of a relatively short period of time in which, in an important technical field, traditional materials are, at the greatest possible speed, being replaced by a new group of materials which 30 years ago still belonged to the curiosities. The reason for this remarkable phenomenon lies in the fact that plastics posses a unique combination of properties which are of prime importance for pipes; they are largely noncorrosive, light, cheap, and easy to install. On the other hand it should not be forgotten that the same plastics have a number of serious deficiencies: they are not very strong, and they are temperature-sensitive and timedependent in their mechanical properties.
Hence, for a successful use of plastics as pipe materials, it is essential to find a proper balance between the strong points and the weak points, by a careful selection of polymer type and grade for each field of application.
In this paper we shall consider the advantages and limitation of the various plastic pipe materials into some detai I, and discuss the new developments made to improve some of the deficiencies.
Related papers
Author(s) : Andreas Moerman, Flip van der Valk, Mirjam Blokker KWR, Tjakko Haaijer, Jan Vreeburg,
Drinking water companies with ageing networks are facing vast amounts of drinking water network reconstructions during the coming decades. This development coincides with the energy transition, which puts pressure on the available space underground. These external drivers give drinking water companies an opportunity...
Author(s) : James F. Mason, Akshay Ponda, Hermann van Laak, Buc Slay
The effects of liquid hydrocarbons on long term strength of pipe grade thermoplastic resins is an important consideration when designing pressure pipe for use in the oil and gas industry. There is an extensive body of work going back several decades descri bing these effects for pipe grade polyethylenes, and all...
Author(s) : Ernst van der Stok
For PE 100-RC, two tests are still under development for pipes: the point load test (PLT) and the accelerated notch pipe test (aNPT). The PLT was developed by a project group consisting of manufacturers and end users. The PLT determines the resistance to point loads as they can occur in practice. An earlier study...
Author(s) : M. Eckes & Dr. B. Baudrit, Dr. M. Troughton & D. Wylie, H. van Laak & J. Fritz
Unplasticized polyamide 12 (PA-U12) is increasingly being used in pipe applications, especially in the gas sector. However, the material behavior in the usual quality tests for pipe welds has not yet been thoroughly investigated. For this reason, two research institutes, worked in cooperation with a manufacturer of...
Author(s) : Sjoerd Jansma, Peter Cloos, Ernst van der Stok
This paper describes two different test methods used to determine the permeation rate of hydrogen through a reinforced thermoplastic pipe (RTP) system with a HDPE liner pipe and a gas-tight layer at a pressure of 42 bar(g) hydrogen and ambient temperature. One method involThe results of the aforementioned tests...
Author(s) : Karel van Laarhoven, Andreas Moerman
Pipe failure in drinking water distribution networks occurs as a result of loadings on the pipe that exceeds its strength. Especially, pipes that deteriorate over time have an increasing probability of failure. Prediction models that estimate when a particular pipe will fail can therefore be valuable tools in pipe...
Author(s) : Hermann van Laak, Jan Heimink, Mario Messiha, Andreas Frank, Christoph Bruckner, Thomas Kratochvilla
For high pressure pipes above maximum operation pressure of 10 bar, this paper emphasizes PA-U12 as the easy to install alternative to steel. It underlines the superb performance of PA-U12 pipes for alternative installation techniques without need for a separate mechanical protection. An unplasticized polyamide 12...
Author(s) : Stefanus Johannes van Vuuren
Biofilm establishes itself over a short period of time in all pipelines conveying raw and treated water. Depending on the type of biofouling, it is documented that it will inevitability lead to a reduction in the hydraulic capacity. Since none of the current design relationships used to calculate the friction loss in...
Author(s) : M. Boerakker, S. van Mierloo, D. v. Beek, R. Schipper, P. Voets, M. Soliman, K. Jacobson, D. Lukes, B. Rabaud, F. Zraick
HDPE pipes are used for standard pressurized water pipes, offering an excellent solution for safe transport of (drinking) water. The HDPE pipe market is growing globally. Especially in countries that suffer from water scarcity, surface water and water from rivers have to be used for drinking water supply. To...
Author(s) : Mario Messiha, Andreas Frank, Isabelle J. Berger, Jan Heimink, Hermann van Laak, Florian Arbeiter, Gerald Pinter
Since the last decade polyamide 12 (PA12) has been successfully introduced as material for SDR 11 gas piping systems up to 18 bar, representing itself as an attractive alternative to steel pipes for high-pressure applications. Practical experience has confirmed that beside the higher strength, PA12 pipe grades ...
Author(s) : Marc van Loo (Dr.), Constant Van Aerschot, KumHoong Lou
In many parts of rural developing Asia and even some parts of Africa, sewerage from households is often discharged directly to the surrounding. This unfortunate fact means that many waterborne diseases such as cholera, dysentery and typhoid continue to afflict these communities. Numerous efforts from governments,...
Author(s) : E.J.W. van der Stok, K. Jacobson, S.O. Jansma, D. Lukes
The lack of a fast, universally-accepted test method for chlorine-dioxide-disinfected water is hindering the development of improved plastic piping materials. A literature survey was performed to define the degradation process in which chlorine dioxide affects the ageing of polypropylene, and to describe and reflect...
Author(s) : E.J.W. van der Stok
The effect of eleven different test parameters on the strain hardening modulus was investigated using the Design of Experiments statistical method. The changes in strain hardening modulus due to temperature, tensile drawing speed and the cooling rate after annealing were assessed. The importance of taking account of...
Author(s) : René Hermkens, Ernst van der Stok, Johannes de Bruin, Jeroen Weller
The replacement of fossil fuels like natural gas by sustainable gases such as biogas and hydrogen can mitigate global warming. There has been some debate about the impact of sustainable gases on the materials used in the gas grid. An extensive study of the behaviour of PE, PVC, POM and rubber materials was therefore...
Author(s) : Ernst van der Stok, Frans Scholten
Samples machined directly from pipe show that orientation has a large influence on the strain hardening modulus. No effects arising as a result of residual stresses were found. Samples machined in the axial direction from a hydrostatic pressurised pipe showed no effect as a result of this mechanical degradation. For...
Author(s) : Johannes de Bruin, Dr. Bert Dalmolen, Albo van Hateren
Normal High Density Polyethylene (HDPE) is commonly used as the fluid contacting element, or the “inner-liner”, in Reinforced Thermoplastic Pipes (RTP) and steel pipes up to 65 ºC. Through a modification of the HDPE polymer matrix, by adding nanoparticles, the E-modulus can be increased. Research shows that...
Author(s) : Frans Scholten, Ernst van der Stok
The residual quality of first generation PE50 gas pipes, installed in Netherland between 1961 and 1979, is still remarkably good. The only premature failures of a few PE50 pipes were exclusively caused by point loads. When under point loading, they started failing in practice after 8 to 26 years, in a brittle manner....
Author(s) : Frans Scholten, Ernst van der Stok, Britta Gerets, Mirko Wenzel, Mike Boege
The current condition of 35-50 years old uPVC main (110 mm) and service (32 mm) pipes for gas and water distribution was assessed. From 27 excavation sites in total about 400 segments of 1.2 meters length each were tested using many techniques. The K-value (average molecular weight) of the PVC, the degree of gelation...
Author(s) : Ernst van der Stok, Jeroen Weller, Frans Scholten
This paper describes falling-weight tests as a first step towards determining the effect of residual stresses on the fracture behaviour of old PVC-U gas pipes at impact. Results showed that the level of surrounding pipe support, the quality of the material and the diameter of the striker had a major effect on the...
Author(s) : Tony Calton, Roel van’t Veer, Henk Meerman
The European plastic pipes and fittings industry has made a commitment through TEPPFA to use a quarter of a million tonnes of recycled material a year by 2020. This presentation provides background to the growth in the use of recycled material for pipe applications and outlines some of the achievements to date and...
Members of the Association
