Runoff behaviour of metallic materials used for roofs and facades - a 5-year field exposure study in Switzerland

Abstract

Different metallic materials, which are in use for building roofs and facades, were exposed to open atmosphere in Dübendorf (Switzerland). The following materials were investigated: copper and zinc with different surface treatment, tinned copper, galvanized steel, aluminium, stainless steel, tinned stainless steel, titanium, and lead. The runoff during rain periods were collected and chemically analysed. It could be shown that copper, zinc and lead release “measurable” amounts of metallic ions and only a small fraction of “particulate” matter. From aluminium, stainless steel and titanium the release was smaller than the detection limit (< 0.01 mg L−1) of the analysis method used. The runoff data will be compared with the corrosion data. The corrosion rate decreases in the course of time whereas the runoff rate shows relatively a constant behaviour.