Polypropylene multi-layer-pipes - 100 year lifetime assessment using linear elastic fracture mechanics

Author(s) : Márton Bredács, Andreas Frank, Amaia Bastero, Alex Stolarz, Gerald Pinter

Accelerated aging experiments by the immersion of a commercial polyethylene (PE) pipe grade in 10 ppm of chlorine dioxide (ClO2) and in 100 ppm of hypochlorite (HOCl) solution at 60 °C were performed. An additional immersion test was conducted in 1 ppm of ClO2 at 40 °C. The exposure parameters were continuously...

Author(s) : Nolene Byrne, Rasike De Silva, Keith Lenghaus, Tim Hilditch

Plastic pipes have been utilized in the Australian gas distribution network since the early 1970s. The most common plastic type found in Australia is polyethylene (PE), although nylon is extensively used in New South Wales. Early installation of PE pipe was completed using the first generation high density type PE50...

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) : Ignacio Muñoz

During the last years PVC-O has become a popular product in pipe business due to the huge improvements of mechanical properties of PVC after orientation. At the same time, CPVC has become an important choice for hot water conduits in in-house applications. Molecor has started a research program to evaluate the...

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) : Anders Andtbacka, Frans Alferink, Peter Sejersen

The behavior of buried plastic pipes is already well described in standards and technical specifications and as well as proven in real life conditions. Plastics pipes in diameters up to around 400 mm are already in use for more than 60 years and pipes with larger diameters for more than 20 years now. All with good...

Author(s) : Davidovski Zoran

To get a deeper insight in why plastic pipes systems in some cases are deselected by designers, installers and users, European Plastics Pipes and Fittings Association (TEPPFA) initiated a research including interviews in four pilot countries: Poland, France, Germany and the UK. The first phase was concentrating on...

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) : Suleyman Deveci, Birkan Eryigit, Senthil K. Kaliappan

The effect of eccentricity on the failure time of pipes under hydrostatic pressure test has a significant magnitude that it can easily mislead the evaluation of pipes according to requirement of ISO 4427-2. Therefore, authors propose a maximum relative eccentricity limit of 0.015, even lower, for pipes being tested...

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) : Christian Schalich

This paper introduces a new technology based on millimeter waves. It provides a noncontact, non-destructive, online measurement of inner and outer diameter, ovality, wall thicknesses, and sagging (sagging of the melt during solidification at a too high viscosity) of large plastic pipes during the extrusion...

Author(s) : C. B. Dandekar

Agriculture is the major occupation practiced in India, and irrigation is therefore a vital part of the entire water budget of the country. India possesses only 4% of the total world’s fresh water resource, of which, more than 80% is consumed solely in the Agriculture Sector (Dhawan, 2017). Canal based distribution...

Author(s) : Isabelle J. Berger, Andreas Frank, Gerald Pinter, David Nitsche, Dirk Petry

Electrofusion (EF) sockets constitute a well-established and practically proven technology for the joining of polyethylene (PE) pressure pipes. As for the pipes, the potential lifetime of such welding connections is beside other properties also depending on the resistance against slow crack growth (SCG). The current...

Author(s) : Bülent Kuzkaya

Spiral wound pipes are becoming more and more important in larger diameter HDPE pipe production technology. The spiral wound structured wall pipes with profiles are already well known and used for several low or non-pressure pipe applications. This paper shows that spiral wound pressure pipes can fulfill the...

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) : Pavel Hutar, Jan Poduska, Pavol Dlhy, Andreas Frank, Jaroslav Kucera, Jiri Sadilek, Gerald Pinter, Lubos Nahlik

This paper investigates possible use of recycled material as a part of a multilayer polyethylene pressure pipe system. Crack propagation in different configurations is simulated. Lifetimes of pipes containing recycled material are calculated. Results are compared with lifetimes of pipes made of virgin...

Author(s) : Jacob John, Andrew J. Ortquist, Mats Thunwall, Patrik A. Roseen

This study investigates production of crosslinked polyethylene (PEX) pipes using a resin obtained from a renewable resource via twin-screw extruder technology. PEX pipes were extruded using petroleum-based and renewable high-density polyethylene (HDPE) for comparison. Testing using relevant ASTM standards on the new...

Author(s) : J.D. Kim, S. Kim , T. Schmutz, C. Malchaire, D. Scholz, K. Keck

Since a few years, pipe producers are facing the challenge to protect their plastic pipe from degradation due to chlorine dioxide. Unfortunately, most existing stabilization solutions are not effective enough to insure the desired lifetime of the material. This study shows how the latest development allow to top-up...

Author(s) : Dongyu Fang, Mark Yu, Zhang Qingfu

In the present paper we introduced how high modulus polypropylene helps an innovative design of utility tunnel up to 4000mm in diameter. High modulus polypropylene shows high modulus but still maintain reasonable flexibility so that tunnel and surrounding soil could form an integrated system, which means no force is...