CONFERENCE REVIEW | PLASTIC PIPES IN INFRASTRUCTURE
advanced techniques such as scanning electron microscopy (SEM), gas chromatography-mass spectrometry (GCMS) and nuclear magnetic resonance (NMR). Kalloudis presented several case studies to
illustrate various types of pipe failure, including hot water PVC pipe and PE100 water pipes. Several failures of the PVC pipe had caused a factory shutdown. Some pipe sections were removed and analysed by DSC – which revealed that the PVC’s glass transition temperature had been lowered – as the elevated temperatures had led to thermal relaxation and resulted in physical ageing.
PE100 water pipe butt welds were exhibiting
brittle mode failures, though no problems were identified in the welding process. The problem was identified through micrographs – which revealed large agglomerates of carbon black. This was confirmed using SEM. In a similar case, a butt fusion-welded PE100 pipe showed excessive blistering on the welding surface – though DSC, FTIR and SEM showed nothing suspicious. However, GCMS revealed trace amounts of a saturated hydrocarbon on the
non-heated side of the pipe – leading to the conclusion that diesel had contaminated the PE100 during processing.
As well as using techniques like these to identify
the reasons for failure, Kalloudis said it was vital to implement effective QA and QC programmes. “Although a lot of research has been done in the
production of PE pipe materials, bad QA and QC processes can threaten the pipelines,” he said. “Contractors and utility companies must establish tight QA/QC procedures and follow the require- ments of the relevant standards.” Joaquín Lahoz Castillo, senior pipe researcher at
CEIS in Spain, described three case studies involving failed PVC pressure pipes. “Longitudinal crack failure in large PVC pipes in
irrigation projects have been a recurrent topic in the last few years,” he said. “We wanted to know if this was caused by rapid crack propagation (RCP), or whether it was about pipe quality.” In the first example, PVC pipes from 2008 were found to have longitudinal fissures and cracks. There were noticeable brown and grey particles visible in the cracks. Tests showed onset tempera- tures below 180°C and a gelation degree of 61%.
...
Don’t miss these issues of
Guill Tool & Engineering is a leading supplier of rubber and plastic extrusion tooling for products ranging in size from 0.005 inch diameter tubing, various size profile extrusions, and up to 20 inch industrial pipe. We offer six or more layer inline dies and crossheads backed by engineering support that's unmatched in the industry.
3D CAD, CFD and FEA software begin our process and all products are made in our quality-first production facility.
“ENGINEERING SOLUTIONS THAT MAKE SENSE”
We welcome all challenges!
www.guill.com tooling@guill.com
West Warwick, Rhode Island (USA)
401-828-7600
COMPOSITE PIPE/ MELT FILTERS
PEX PIPE/ TIO2 MARKETS
CLICK ON THE COVERS TO VIEW
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56
