University Study Questions Safety of Steam-Cured Pipe Lining

The National Association of Sewer Service Companies prepares to bring in third party to do further research, cites concerns about ‘inconsistencies’ in Purdue University study

University Study Questions Safety of Steam-Cured Pipe Lining

For their study, Purdue University researchers did air testing at seven steam-cured CIPP installations in California and Indiana. (Photo by Purdue University)

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A Purdue University study published in July about the potential release of toxic chemicals during the CIPP process has the National Association of Sewer Service Companies preparing to do its own study.

NASSCO is currently requesting research proposals through October for a third party to do a study, which would include a review of recent publications related to emissions and the CIPP installation process as well as additional sampling and emissions analysis during field installation, specifically using the steam-curing process.

The Purdue study, led by Andrew Whelton, looked at seven steam-cured CIPP installations in California and Indiana. Researchers did air testing to measure the concentration of various chemical compounds potentially emitted by the process. They concluded that the plume from the steam-curing process is a complex mixture of organic vapor, water vapor, particulates of condensable vapor and partially cured resin, and liquid droplets of water and organic chemicals. Concentrations were affected by wind direction and speed.

“CIPP is the most popular water-pipe rehabilitation technology in the United States,” says Whelton in an article on “Short- and long-term health impacts caused by chemical mixtures should be immediately investigated. Workers are a vulnerable population, and understanding exposures and health impacts to the general public is also needed.

“CIPP workers, the public, water utilities, and engineers think steam is emitted. What we found was not steam. Even when the chemical plume was not visible, our instruments detected that we were being chemically exposed.”

But industry groups like NASSCO have examined the details of the Purdue team’s study and are questioning the findings.

“It is clear that NASSCO guidelines and specific quality and safety protocols were not utilized during the testing performed, nor referenced in the study by the university,” says Ted DeBoda, NASSCO executive director, in a statement in response to the Purdue study. “This is of great concern to NASSCO and other organizations aligned to our industry that continually use, monitor and evaluate the effectiveness and safety levels of CIPP technology. It is difficult for us to understand how a representative team from a reputable university would not fact check their information and assumptions before publishing such critical information to the public.

“A review of the data released in the initial Purdue study indicated a number of inconsistencies that had not been experienced or documented previously in the industry. This is based on extensive testing performed around the world. To our understanding, these data were not considered before coming to a final conclusion or publication of the report.”

According to NASSCO, by bringing in a third party to head up another study, the hope is to provide some definitive answers to the questions Purdue researchers raised.

“There is concern that Dr. Whelton’s team found certain other organic chemicals in the steam exhaust and other release points of CIPP installations where steam was used to heat the curing resin,” says DeBoda in his statement. “While there are questions regarding the presence and source of these organics (whether their origin is the actual CIPP product, another substance present in the CIPP process, or contained in the existing environment), in the best interest of our members and communities, NASSCO will certainly investigate further.”


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