Related papers
2016 Berlin : Determining the residual quality of PE pipes using the strain hardening testAuthor(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...
2016 Berlin : Predicting the lifetime of PE50 gas pipes under point loadingAuthor(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....
2016 Berlin : Residual quality of excavated UPVC gas and water distribution pipelinesAuthor(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...
2014 Chicago : Designing Against Rapid Crack Propagation in PVC Water PipesAuthor(s) : Frans Scholten, Ernst van der Stok, Jan Breen
Very occasionally PVC-U water pipes suddenly fail due to a long brittle crack with a length of many meters which propagates with the speed of sound along the pipe and causes extensive water loss. This phenomenon has been recognized as Rapid Crack Propagation (RCP). The conditions under which RCP can occur are an...
2014 Chicago : Two Complementary Tests to Determine the Quality of PE 100RCAuthor(s) : Ernst van der Stok, Frans Scholten
The Strain Hardening (SH) test and the Point Load Test (PLT) are two complementary tests designed to determine the quality of PE 100-RC. The SH test is a resin test, whereas the PLT is a pipe test. The SH test is a tensile test performed at 80 °C. Extensive research on the SH test has been conducted and published in...
2012 Barcelona : Strain hardening tests on PE pipe materialsAuthor(s) : Van der Stok, Scholten
The Strain Hardening (SH) test developed by Kurelec et al. has been applied to a variety of PE pipe and resin materials. The clear trend in the strain hardening modulus, of first, second and third generation PE pipe resins and PE100 RC pipe resins, illustrates the large progress in resin quality during the past four...
2010 Vancouver : Cover blow-off resistance of reinforced thermoplastic pipes for gas serviceAuthor(s) : E.J.W. van der Stok, F.L. Scholten, L.G.P. Dalmolen
A mathematical model was set up to assess the equilibrium gas pressure in the annulus of the
reinforcement layer of an RTP pipe. This is done by using the theory of gas permeation, ruled
by Fick's Law and the theory for a temperature gradient over the pipe wall, ruled by Fourier's
law. The model allows calculating the...
2010 Vancouver : Pa pipes for 16 bars gas pipelinesAuthor(s) : Frans Scholten and Mannes Wolters
PA11, PA12 and plasticized PA6.12 pipes are interesting candidates for gas transport and
distribution pipelines at 16 bars pressure, which is beyond the maximum pressure for
PE100 pipeline systems (10 bars). However, PA pipelines are not meant as an alternative
to PE pipelines, but to steel pipelines. Therefore,...
2010 Vancouver : Residual quality of first generation PE gas and water pipesAuthor(s) : F.Scholten
Segments from 32 mm gas service pipes installed in 1975-1976 and from 40 mm water
service pipes installed in 1967-1968 in Germany have been excavated and tested for
residual quality. Two different HDPE resin populations discovered among the German
gas pipes were also found among excavated Dutch gas pipes. Internal...
2001 Munich : Opportunities for Plastics in Flexible Indoor Gas Pipe SystemsAuthor(s) : Oesterholt, Scholten, Roebers
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...
1998 Gothenburg : Welding of Peroxide, Silane and Electron Beam Crosslinked PE PipesAuthor(s) : Scholten, Wolters
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...
1992 Eindhoven : Field failures in PE Gas Pipes - Analysis versus Lifetime PredictionAuthor(s) : Scholten, Rijpkema
Eight excavated HDPE pipes of the 1st generation
along with 3 modern PE types have been investigated. Comonomer content as a function of molecular
weight of the old HDPE pipes appeared to be nonoptimal with respect to the modern PE types. Further unwanted effects in the old pipes were :
particles, oxydation,...
Methane Permeation through Advanced High-Pressure Plastics PipesAuthor(s) : Scholten, Rijpkema
The Slow Peel Test as a Tool for Assessing the Integrity of Electro Fused JointsAuthor(s) : Scholten, Wolters
