Amaia Bastero, Márton Bredács, Andreas Frank
Papers # 2016 Berlin
The effect of chlorinated water environment to plastic pipes has been intensively investigated in recent years and proved to affect the lifetime of plastic pipes. Since it is known that the use of the different disinfectants (ClO2, HClO/ClO- ) imply different degradation rates, understanding the conditions (concentration, time) which lead to the same degradation speed is key to set testing conditions comparable for the different media. The test results will be compared to those obtained when the materials are tested as pipes following ASTM 2023-13, to ensure the validity of the test as a rating tool.
To guarantee safe human consumption often the drinking water is disinfected so that the pathogenic microorganisms are removed, deactivated or killed. The disinfectants act oxidizing the organic matter present in the water and therefore preventing bacteria growth. Depending on the region, different regulations apply to the level of disinfection required for drinking water. There are several procedures for water disinfection such as the addition of chlorine, chlorine dioxide (ClO2), ozone or chloramines.
The effect of chlorinated water environment to plastic pipes has been intensively investigated in recent years and proved to affect the lifetime of plastic pipes. In US there is a requirement for plastic pipes in contact with drinking water as described in ASTM F2023 using chlorine (hypochlorite) as oxidizing media. In Europe ClO2 is also used as disinfectant to treat potable water. Since it is known that the use of the different disinfectants imply different degradation rates, this study has focused on the comparison of the degradation rates of several PE pipe resins submitted to ClO2 vs. hypochlorite systems at comparable conditions. Understanding the conditions (concentration, time) which lead to the same degradation speed is key to set testing conditions comparable for the different media. The idea of this study was to develop a faster test than the aforementioned ASTM method performed on pipes, while ensuring constant conditions of the exposure medium. Such a test should allow generating qualitative rating on resistance to oxidative degradation of resins in different chlorinated media, so that faster assessments can be done in the course of new resin development.
