Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Corrosion-induced copper release from rain gutters
While runoff rates from copper roofs have been extensively studied during the last years, corresponding studies from copper rain gutters have been missing. A laboratory investigation has been undertaken to examine the influence of important runoff water parameters on the copper runoff from rain gutters. At a given rainfall quantity, the release rate of copper increases with decreasing runoff water intensity and decreasing degree of gutter inclination, and with increasing runoff acidity and increasing Cu(exp2+)-ion concentration in the runoff water. A comparison of the predicted long-term copper release from the gutter-system compared to the roof on a real building suggests that less than 5% of the total copper runoff originates from the gutter. However, single rain events may result in higher release rates, especialla the initial rain portion. General conclusions: A laboratory investigation has been performed to examine the influence of important runoff water parameters on the copper runoff from rain gutters. From generated data a statistical model has been derived in order to predict copper runoff concentrations from gutters during specific rain events. The study includes also a comparison of predicted long-term copper runoff from gutters and roofs. At a given rainfall quantity and degree of inclination, the release rate of copper increases with decreasing rain intensity as a result of longer residence time between impinging runoff water and the patinated copper surface. An increasing degree of gutter inclination from the horizontal results in a higher flow rate of runoff water and a shorter residence time for runoff water on the copper surface, hence lower release rates of copper from the gutter. The release rate of copper increases significantly with decreasing acidity. Steady state concentrations vary between 0.05 (for runoff pH = 6.2) and 0.18 (pH 4.3) mg Cu L(exp-1), respectively, in reasonable agreement with literature field data respectively. The presence of Cu(exp2+) ions in the runoff water before entering the copper gutter results in increasing release rates of copper due to an additional reaction path for copper release. Predictions of the copper release from copper gutters compared to a copper roof on an existing building in Stockholm, Sweden, suggest a small contribution (less than =5%) from the gutters on an annual perspective. Single rain events may however result in higher release rates, especially during the intial rain portion.
Corrosion-induced copper release from rain gutters
While runoff rates from copper roofs have been extensively studied during the last years, corresponding studies from copper rain gutters have been missing. A laboratory investigation has been undertaken to examine the influence of important runoff water parameters on the copper runoff from rain gutters. At a given rainfall quantity, the release rate of copper increases with decreasing runoff water intensity and decreasing degree of gutter inclination, and with increasing runoff acidity and increasing Cu(exp2+)-ion concentration in the runoff water. A comparison of the predicted long-term copper release from the gutter-system compared to the roof on a real building suggests that less than 5% of the total copper runoff originates from the gutter. However, single rain events may result in higher release rates, especialla the initial rain portion. General conclusions: A laboratory investigation has been performed to examine the influence of important runoff water parameters on the copper runoff from rain gutters. From generated data a statistical model has been derived in order to predict copper runoff concentrations from gutters during specific rain events. The study includes also a comparison of predicted long-term copper runoff from gutters and roofs. At a given rainfall quantity and degree of inclination, the release rate of copper increases with decreasing rain intensity as a result of longer residence time between impinging runoff water and the patinated copper surface. An increasing degree of gutter inclination from the horizontal results in a higher flow rate of runoff water and a shorter residence time for runoff water on the copper surface, hence lower release rates of copper from the gutter. The release rate of copper increases significantly with decreasing acidity. Steady state concentrations vary between 0.05 (for runoff pH = 6.2) and 0.18 (pH 4.3) mg Cu L(exp-1), respectively, in reasonable agreement with literature field data respectively. The presence of Cu(exp2+) ions in the runoff water before entering the copper gutter results in increasing release rates of copper due to an additional reaction path for copper release. Predictions of the copper release from copper gutters compared to a copper roof on an existing building in Stockholm, Sweden, suggest a small contribution (less than =5%) from the gutters on an annual perspective. Single rain events may however result in higher release rates, especially during the intial rain portion.
Corrosion-induced copper release from rain gutters
Korrosionsinduzierte Entkupferung von Regenrinnen
Bahr, B. (Autor:in) / Odnevall Wallinder, I. (Autor:in) / Leygraf, I. (Autor:in)
Metall - Internationale Fachzeitschrift für Metallurgie ; 62 ; 129-135
2008
7 Seiten, 7 Bilder, 2 Tabellen, 38 Quellen
Aufsatz (Zeitschrift)
Englisch