Extensive testing on PVC sewer pipes towards identifying the factors that affect their operational lifetime
TL;DR: In this article, the authors show that polyvinyl chloride (PVC) sewer pipes have operated for decades in a hostile environment, raising concern among sewer managers over the longevity of their drainage systems.
Abstract: Polyvinyl chloride (PVC) sewer pipes have operated for decades in a hostile environment, raising concern among sewer managers over the longevity of their drainage systems. Inspection data (CCTV and...
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TL;DR: In this article , the authors examine the associated evidence base for using plastic materials for restoration, and provide some suggestions for a path forward, concluding that the use of plastic for habitat enhancement or restoration in freshwater systems is nothing short of littering.
Abstract: The creation and deployment of plastic structures made out of pipes and panels in freshwater ecosystems to enhance fish habitat or restore freshwater systems have become popularized in some regions. Here, we outline concerns with these activities, examine the associated evidence base for using plastic materials for restoration, and provide some suggestions for a path forward. The evidence base supporting the use of plastic structures in freshwater systems is limited in terms of ecological benefit and assurances that the use of plastics does not contribute to pollution via plastic degradation or leaching. Rarely was a cradle-to-grave approach (i.e. the full life cycle of restoration as well as the full suite of environmental consequences arising from plastic creation to disposal) considered nor were decommissioning plans required for deployment of plastic habitats. We suggest that there is a need to embrace natural materials when engaging in habitat restoration and provide more opportunities for relevant actors to have a voice regarding the types of materials used. It is clear that restoration of freshwater ecosystems is critically important, but those efforts need to be guided by science and not result in potential long-term harm. We conclude that based on the current evidence base, the use of plastic for habitat enhancement or restoration in freshwater systems is nothing short of littering.
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TL;DR: In this article , the potential of vibro-acoustics to detect physical ageing of plastic pipes was explored, where the axisymmetric water-borne wave was used to quantify the storage modulus of a plastic pipe and an uncertainty analysis revealed the parameters that must be more accurately known.
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01 Jan 2007
1,323 citations
TL;DR: The general area of physical aging of polymers is reviewed in this article, where various phenomenological aspects are introduced and discussed in terms of bulk structural changes evidenced by dilatometric and calorimetric studies, and are compared with the wide variety of information available from microstructural investigations involving spectroscopic and scattering techniques.
895 citations
601 citations
TL;DR: In this paper, the performance of unpigmented and rutile titanium dioxide pigmented rigid polyvinyl chloride (PVC)/wood-fiber composites has been studied.
Abstract: Ultraviolet (UV) weathering performance of unpigmented and rutile titanium dioxide pigmented rigid polyvinyl chloride (PVC)/wood-fiber composites has been studied. The composite samples were manufactured by dry-blending PVC, wood fibers, and other processing additives in a high-intensity mixer. The dry-blended compounds were extruded and compression molded into panel samples. The manufactured samples were artificially weathered using laboratory accelerated UV tests. Composite samples were exposed to 340-nm fluorescent UV lamps and assessed every 200 h, for a total of 1200 h of accelerated weathering. Each assessment consisted of a visual examination of surface roughness or erosion, a contact angle measurement, a FTIR collection, and a color measurement. The experimental results indicated that wood fibers are effective sensitizers and that their incorporation into a rigid PVC matrix has a deleterious effect on the ability of the matrix to resist degradation caused ultraviolet irradiation. The light stability of these composites could be improved quite efficiently with the addition of rutile titanium dioxide photoactive pigment during formulation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1943–1950, 2001
137 citations
TL;DR: In this article, the authors assess the quality of the analysis of visual sewer inspection data by analysing data reproducibility; three types of capabilities to subjectively assess data are distinguished: the recognition of defects, the description of defects according to a prescribed coding system and the interpretation of sewer inspection reports.
Abstract: In common with most infrastructure systems, sewers are often inspected visually. Currently, the results from these inspections inform decisions for significant investments regarding sewer rehabilitation or replacement. In practice, the quality of the data and its analysis are not questioned although psychological research indicates that, as a consequence of the use of subjective analysis of the collected images, errors are inevitable. This article assesses the quality of the analysis of visual sewer inspection data by analysing data reproducibility; three types of capabilities to subjectively assess data are distinguished: the recognition of defects, the description of defects according to a prescribed coding system and the interpretation of sewer inspection reports. The introduced uncertainty is studied using three types of data: inspector examination results of sewer inspection courses, data gathered in day-to-day practice, and the results of repetitive interpretation of the inspection results. After a thorough analysis of the data it can be concluded that for all cases visual sewer inspection data proved poorly reproducible. For the recognition of defects, it was found that the probability of a false positive is in the order of a few percent, the probability of a false negative is in the order of 25%.
120 citations