DIPRA pays diligent attention to detail to learn and advise on how Ductile iron pipe performs – and how to continue to improve its value to utilities.
Fallacies in Research Citations Raise a Flag of Warning on Believability - And Trust
There they go again! In a recent email blast, the Uni-Bell PVC Pipe Association (Uni-Bell) tried to turn facts upside down, this time asserting that a DIPRA brochure on cement-mortar linings contains evidence of a deteriorating Hazen-Williams flow coefficient. Uni-Bell’s attempt is an incredibly obvious effort to obfuscate fact by desperately grasping for an advantage that they do not have compared to Ductile iron pipe. Uni-Bell is struggling to overcome the energy disadvantage that exists when pumping through PVC pipe as compared to Ductile iron’s larger cement-mortar lined inside diameter. (Bonds 2017, Thomas 2016, McPherson 2009, Gaston 2014). Truth be told, Ductile iron’s on top.
Uni-Bell’s arguments often involve disparaging their competition, with a heavy, disrespectful belief that its audience is credulous and gullible. For example, under the heading, “A Significant Body of Research Also Disagrees with DIPRA,” Uni-Bell cites references that, when you take the time to read them, mostly say the opposite of what Uni-Bell claims. It’s a twist of facts to serve a scurrilous objective and demonstrates that, when Uni-Bell makes an argument, it automatically requires scrutiny to determine the fallacies. That, in itself, is a flag of warning as to believability – and trust. As an example, Uni-Bell cites an article by Sharp and Walski published in the November 1988 Journal AWWA (Walski 1988) saying, “Army Corps of Engineers – developed (an) equation for determining ‘C’ values for corrosion-prone pipe at any age based on roughness growth rate.” But, that article begins, in its introduction, “(t)he equations presented provide a quick method for predicting C-factors…in unlined metal pipes (emphasis added).” The article goes on to say, “(i)n modern cement-mortar lined and plastic pipes, internal roughness changes very slowly over the life of a pipe…”
Again, the truth is that there are ample technical articles and reports published by Journal AWWA, the Water Research Foundation, ASCE and others confirming the long-term viability of cement-mortar linings. (Muster 2011, Water Research Foundation 2011, Lee 2011, McPherson 2009, WSA Australia 2002, Hall 2013, Welch 1971, Miller 1965, Lamont 1981).
Another egregious effort is in Uni-Bell’s assertion that “DIPRA’s Testing Conflicts with Its Own Recommendations,” where they claim our brochure, “Cement-Mortar Linings for Ductile Iron Pipe,” belies a hidden discrepancy. It doesn’t. The DIPRA brochure includes the results of field tests conducted on in-service pipelines of various ages and locations where the C factors were measured. 43 flow test results were presented, with values ranging between 130 and 148 in pipelines from 5 to 77 years in service. It is the average of those measured results that was the basis for our recommended C value of 140.
Uni-Bell asserts their analysis found “(a) 12-inch cement-mortar lined iron pipe (sic) Greenville, TN had a degradation rate of 0.46 per year.” They cited eight such evaluations but, as is typical with Uni-Bell, did not “show their work.” The arithmetic was simple. Here, they subtracted the result from one of three Greenville, TN measurements (134 – the lowest of the three results), subtracted this from DIPRA’s recommended C value (140) and divided by the age of the pipe (13 years) to get 0.46!
This is shameful. DIPRA published three results for Greenville, TN: 134 (13 years), 137 (29 years) and 146 (36 years). Using Uni-Bell’s flawed method, Greenville demonstrates an improvement over time – with the last result indicating the C factor having increased by 0.17 per year!
The examples found in this Uni-Bell brief are too many to list, here. For the whole truth, an assessment is available by following this link,
DIPRA pays diligent attention to detail to learn and advise on how Ductile iron pipe performs – and how to continue to improve its value to utilities. We do so out of respect for those who design and operate a vital infrastructure; and we do so because many of us have been there, doing those jobs. Uni-Bell’s efforts exemplify the “man behind the curtain” pretending to be a wizard. With this caliber of work, Uni-Bell will give us years of opportunities to fact-check, which we will do when we can break away from the more serious work we have ahead of us. The kind of work that actually helps utilities improve their systems.