Plastic Pipes Conference Association # 1995 Edinburgh
Gueugnaut, Rousselor
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 pipes midwall by means of a stepwise thermal program using Differential Scanning Calorimetry. The quantita tive evaluation of the crystallization exothermal peaks along with that of the related half crystallization times gives way to a fairly accurate determination of the kine tic parameters on the one hand and to the evaluation of the proportions of the crystallizable species at 2 diffe rent temperatures on the other hand. The data obtained enlight a sharp variation of the resin characteristics from ca. 1991 and confirm earlier trends on this mate rial independently of the pipes extrusion conditions. A comparison with data obtained on both a so-called 1st generation HDPE and a 3rd generation HDPE pipes from the same resin supplier brings strong evidence of the influence of specific crystallizable species regarding slow crack growth resistance and demonstrates the effi ciency of such methodology for the detection of batch to-batch variations at the most intimate level.
Related papers
Author(s) : Dominique GUEUGNAUT, Pascal AUSSANT, Romuald BOUAFFRE, Myriam BECHROURI
Concerns regarding the environment and sustainable development have revived interest in the reprocessing and re-use of polymer materials from manufactured objects that have reached the end of their operating life. Within this framework, formal professional agreements have been put in place at global level under the...
Author(s) : Dominique GUEUGNAUT, Manuel TESSIER, Romuald BOUAFFRE
Given the virtual absence of available up-to-date results regarding the acceptance criteria for defects at electro-welding interfaces, a study has been launched by GRTgaz RICE with the two-fold aim of confirming the accuracy of the PAUT technique for the detection and sizing of calibrated pit-shaped defects implanted...
Author(s) : Dominique GUEUGNAUT, Adil BOUJLAL, Aymeric LOPITAUX, Bertrand SEVRE
A special concept has been developed by GRTgaz Research and Innovation Center for Energy (RICE) for temperature mapping at the interface of an electrowelded assembly.The technical solution consists of a tubular piece in place of the real PE pipe, made of a non-weldable polymer with thermal parameters close to those...
Author(s) : Dominique GUEUGNAUT, Charles FERNANDEZ, Romuald BOUAFFRE, Bertrand SEVRE, Florent ANGELINI
Representative earthquake loadings have been reproduced in the ENGIE Lab-CRIGEN laboratories on three PE grades, including an excavated old PE63 pipe operated during more than 35 years. Dynamic loading does not alter the pipe residual performances for the three PE families tested, as shown by both the hydrostatic...
Author(s) : Dominique GUEUGNAUT, Adil BOUJLAL, Aymeric LOPITAUX, Romuald BOUAFFRE
A specific methodology has been designed by ENGIE’ R&T Division to allow an accurate determination of the initiation (incubation) time of the NCBT data. This methodology is based on two different data processing procedures. The first data processing proceeds from searching the minimum of the second derivative of both...
Author(s) : Dominique GUEUGNAUT, Florent ANGELINI, Romuald BOUAFFRE, Manuel TESSIER
A test campaign has been carried out by ENGIE Lab-CRIGEN in order to evaluate the acuity of the Phased Array Ultrasonic Technique (PAUT) for detecting and sizing calibrated defects implanted at the inner surface of a PE pipe.These calibrated defectshad four different geometries, called “V-shaped”, “half-V shaped “,...
Author(s) : GUEUGNAUT Dominique, BOUJLAL Adil, BOUAFFRE Romuald, LOPITAUX Aymeric
The emergence of a new generation of PE100, named PE100 RC, with a significant enhanced Slow Crack Growth (SCG) resistance enlights the need for new testing methods in order to be able to test such resins in reasonable test durations. Consequently in the last five years some new tests have been designed to assess for...
Author(s) : GUEUGNAUT Dominique, ANGELINI Florent, BOUJLAL Adil, BOUAFFRE Romuald, SEVRE Bertrand, LOUET Patrick
Polyethylene (PE) is a widespread material for the manufacturing of gas and water distribution pipelines and a large number of PE electrofusion pipe joints can be found over the thousands of kilometres of PE pipeplines all over the world, thus generating an increasing interest in checking the quality of these joints....
Author(s) : Chebbo Z., Boujlal A., Gueugnaut D., Vincent M., Tillier Y.
(Electrofusion, Finite Element, Heat transfer, Interdiffusion, crystallisation and melting Kinetics, Micro-sampling) Electrofusion (EF) is widely used to join polyethylene (PE) components in the gas distribution networks. This paper provides experimental and 3D-finite element tool capable of reproducing the major...
Author(s) : Gueugnaut Dominique, Boujlal Adil, Rousselot Denise, Bouaffre Romuald
(Polyethylene, SIS technique,Micro-sampling) The use of polyethylene(PE) since the early seventies on the GDF SUEZ’ distribution networks has lead to the coexistence of a very wide variety of PE resinswith significant differences in their long term performances. Nevertheless, in order tojustify a possible delayed or...
Author(s) : Gueugnaut Dominique
(Polyethylene, Non destructive technique, Ultrasonic Phased Array, Slow Crack initiation time) Since a few years it has been proved that - among the available concepts - the Ultrasonic Phased-Array technique (PA UT) was one of the most promising candidate for Non Destructive and Non Intrusive analysis of PE and...
Author(s) : Gueugnaut, Berthier, Darut, Constantinescu
It is well known today that rock impingement is one of the major cause of long term failure of PE pipes when in the ground. This phenomenon which results of an intermittent or permanent contact of a hard object – most often not directly injurious – with the PE pipe can lead to premature brittle failure within...
Author(s) : Scholten, Gueugnaut, Berthier
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) : Bon, Gueugnaut, Marty
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...
Members of the Association
