An Evaluation of Aged MDPE Gas Pipes

Author(s) : Yilaing He, Tianjun Zhang

A new electrofusion PE belt is developed by reinforcing it with various layers of steel mesh. It’s of sandwich structure, consisting of steel mesh reinforcement, heating wire and polyethylene. One or more layers of steel mesh is encapsulated in the middle, and heating wire is embedded onto “inner side” of the belt....

Author(s) : Thomas R. Kratochvilla, Raimund Eremiasch, Christoph Bruckner

In the last years effort has been made to develop and standardise new accelerated test methods to evaluate PE 100-RC materials in short times in form of test bars. The two most important developments, the cracked round bar test (CRB test) and the strain hardening test (SH test) were published as final ISO standards in...

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) : Gerald Pinter, Florian Arbeiter, Johannes Wiener, Andreas Frank, Otmar Kolednik

In order to further increase the fracture toughness of pipes, biomimetic layer design of the pipe wall can be used. Therein, soft polymer interlayers can act as crack-arresters in a matrix of stiffer and inherently more brittle polymers. The effectiveness of the crack arresting role of soft interlayers in a...

Author(s) : Markus Gall, Reinhold W. Lang, Joerg Fischer, Ansgar Niehoff, Steven Schmidt

Despite recent efforts in promoting the utilization of recycled polymeric materials for more diverse and more advanced applications, there are still significant knowledge gaps with regards to the applicability of certain recyclate types for specific “re-use” purposes. When it comes to pipe applications, for instance,...

Author(s) : Wang Zhanjie

As the largest production country, with numerous applications, China’s plastic pipe industry is developing steadily to meet the demand and needs. This paper analyzes the current situation and barriers, and proposes the breakthroughs to achieve a sustainable, stable and healthy development of China’s plastic pipe...

Author(s) : Jiang Tongjun, Fu Zhimin, Yang Yuanjin

This paper introduces the application of CPVC pipe in fire sprinkler systems in China. The advantages and differences of CPVC pipe versus to galvanized steel pipes, the improvement of related laws and regulations and the market outlook are discussed. The overall result is a change in the upstream and downstream...

Author(s) : Liang Yu, Akshay Ponda, Dane Chang

Following the development of US shale oil and gas production since 2007, the demand for thermoplastic pipes with better corrosion resistance, and lower installation and operation cost than carbon steel pipe, has been growing significantly. Nylon 12 has been qualified for hydrocarbon transportation in offshore flexible...

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 also...

Author(s) : Ernest Lever

Six different polyethylene materials were tested using Cyclic Pressure Fatigue (CPF) as the accelerating process to correlate the results to conventional long-term hydrostatic test results that were previously developed as part of the material qualification process. The designation of the materials was unknown to the...

Author(s) : HU Fa, LI Yue, GAO Yuanjie, ZHE Dongmei, WEI Ruoqi

This paper expounds the development status of composite insulating pipe in the heating and chemical fields from the aspects of materials, structure and application. Combined with the relevant standards and technical requirements, the performance advantages and the key evaluation methods such as axial shear strength,...

Author(s) : Joerg Fischer, Paul J. Freudenthaler, Patrick R. Bradler, Reinhold W. Lang, Susan C. Mantell

This research addresses the effect of nucleation on the global aging behavior and the fatigue crack growth (FCG) resistance of commercial alpha- and beta-nucleated polypropylene random copolymer pipe grades (PP-R) when exposed to chlorinated water (5 mg/l free chlorine) at an elevated temperature of 60°C. Comparing...

Author(s) : Suleyman Deveci, Nisha Preschilla, Birkan Eryigit

Pipes with inhomogeneous CB distribution showed 80% less elongation than pipes with homogenously distributed CB. Polymer domains with less or no CB (windows) showed delamination from the polymer matrix as the material elongated, finally leading to fracture much earlier than expected. In this study, we investigated the...

Author(s) : John Kurdziel, Michael Pluimer

Corrugated HDPE pipes have been successfully used for decades for sewers, culverts and land drainage applications and are advantageous due to their durability and service life in a variety of installation conditions. Pipes used for highway and storm sewer applications typically require stricter material standards than...

Author(s) : Carlos Domínguez, Álvaro Pérez, Nuria Robledo, Cristina González, Beatriz Paredes, Rafael A. García-Muñoz

Last methodologies for fast evaluation of the SCG resistance on polyethylene pipe materials are analyzed in this work and compared with traditional PENT and FNCT tests. Strain Hardening (SH), Crack Round Bar (CRB) and Accelerated Creep Test (ACT) will be good alternatives for evaluating PE100RC resins. Moreover, SH...

Author(s) : Vivek Rohatg, Gregor Hiesgen, Mark J. Lamborn, Ashish M. Sukhadia, Douglas E. Simpson, David W. Borrego, Pamela L. Maeger

Maintaining dimensions within specifications is problematic for the extrusion of large diameter thick-wall polyethylene (PE) pipe (> 75 mm wall) due to sag caused by insufficient resin melt strength. However, sag can be controlled through careful resin selection and optimization of the pipe cooling process. This paper...

Author(s) : Joerg Fischer, Patrick R. Bradler, Reinhold W. Lang

In the present paper, a novel test system for conducting fatigue crack growth (FCG) experiments under superimposed mechanical-environmental conditions is presented. FCG experiments were performed on a polypropylene (PP) grade and a short-glass fiber reinforced polyamide 66 (PA-GF) grade as model materials. The...

Author(s) : Mitsuaki TOKIYOSHI, Gentaro TAKAHARA, Joji HINOBAYASHI, Toshinori KAWABATA, Takashi KURIYAMA

Glass fiber reinforced polyethylene pipes and fittings are controlled for bending characteristics (Strength and stiffness) for vertical and axial directions of pipe by spiral cross winding method. Generally, to use this method, it takes much stronger for vertical strength than axials cause of extruded direction,...

Author(s) : Michael Pluimer, Richard Thomas

Over the past decade, there have been several key research projects to evaluate the performance of corrugated HDPE pipes manufactured with post-consumer and postindustrial recycled materials for highway and railroad drainage applications. Three of these projects were recently completed and published (NCHRP Project...

Author(s) : Ali Al Hammadi, Shane R. Schuessler, Mohamed Ali Awadh Jaber

This paper presents the advancements of HDPE piping materials, design and installation for use in ASME Class 3 piping systems at nuclear power plants. The paper will specifically introduce details of the first ever ASME Class III nuclear new build use of Class 3 HDPE pipe and fittings at the Emirates Nuclear Energy...