PROCESSING | STANDARDS AND TESTING


global warming, acidification, eutrophication, ozone depletion, and smog formation. “In all categories, corrugated HDPE pipe made


Above: PPI says corrugat- ed HDPE pipe made with recyclate has a lower environ- mental burden than other materials


classification testing to pipe stiffness, and hydro- static pressure testing to elevated temperature testing, Sciteq’s equipment helps us get the work done efficiently, accurately, and safely.”


Corrugated advantage Corrugated high-density polyethylene (HDPE) pipe has the lowest environmental burden compared to other typical stormwater drainage and culvert pipe, according to the Plastics Pipe Institute. PPI commissioned a lifecycle assessment (LCA)


study from Franklin & Associates. The full report (Life Cycle Assessment of North American Stormwa- ter Pipe Systems – TR-53) is available free on PPI’s website. “This LCA investigated reinforced concrete,


corrugated steel, PVC, and two types of corrugated HDPE pipe,” said Daniel Currence, director of engineering at PPI’s drainage division. “HDPE pipe made with virgin resin and HDPE pipe made with recycled content were found to have the best overall sustainability rating.” The analysis evaluated the pipe systems in all life-cycle phases, including raw material extraction, pipe material production, fabrication, installation, repair, and end of life. The study was conducted following internationally accepted ISO standards for LCA methodology, said PPI. It compared 1000 linear feet of 24in diameter storm sewer pipe. “When faced with input decisions that might sway the assessment, we chose to use values that actually benefited competing materials,” said Currence. “We also used competing materials’ own, publicly reported environmental data. The study still recognised that corrugated HDPE pipe as the most environmentally friendly storm sewer material available.” The LCA evaluated the pipe materials across many environmental impact categories, including energy demand, solid waste, water consumption,


26 PIPE & PROFILE EXTRUSION | May 2021


with recycled resins had the lowest impact,” said Currence. “HDPE pipe made with only virgin resins followed closely behind. For global warming potential, corrugated HDPE pipe had approximate- ly 50% of the potential impact of concrete and corrugated steel pipe.” The LCA study was carried out by PPI in order to identify and address the varied pieces of informa- tion about the environmental impact of pipe. “There are a lot of claims about sustainability among competing materials and they are all scattered – so we felt it would be a good idea to capture them all in one place for analysis,” said Currence. “Using the ISO methodology enabled the LCA to provide a realistic comparison.” PPI estimates that a standard 20ft length of 48in diameter HDPE pipe, made with 40% or more recycled material, might use the equivalent of 1,600-2,200 bottles – which could have gone to landfill.


Burst limit Chinese researchers have carried out a study of “defective” PE80 and PE100 gas pipe, to determine how safe it is to use. The research was published in the Journal of


Physics. Three of the five researchers were from Zhejiang Zheneng Natural Gas. Although PE materials are commonly used for


gas transport, the researchers say there are “few researches on the safety performance evaluation of PE pipes”. This, they said, made it difficult to determine “the safety status of defective PE pipes”. The researchers carried out mechanical testing – such as tensile testing – of samples from pipes. They also constructed nine different simulations for each material – using finite element analysis (FEA) – to determine the effect of ‘local thinning’ of pipe. The researchers used Abaqus to create the simu-


lations – of a 9.1mm thick pipe, with a diameter of 160mm. Each simulation incorporated a different defect – in the form of a thickness variation. Each one was then associated with an internal pressure limit – for both PE80 and PE100 pipe. The results showed that defect depth had the


greatest impact on limiting internal pressure. This was more important than both axial length (which had the second largest impact) and circumferential length (which had the least impact). “In practical engineering application, we should


attach special attention to the defect depth found in the test of polyethylene pipes,” said the researchers.


www.pipeandprofile.com �


IMAGE: PPI


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