Introduction
Stainless steels EN 1.4301 and 1.4401/1.4404 are normally considered corrosion resistant in low chloride natural waters like drinking water [1]. However, for Danish and Finnish stainless steel installations a number of corrosion failures have been observed in e.g. fire protection systems and drinking water installations, where stagnant conditions or periods of low water consumption have occurred prior to the failure. Corrosion attacks are found in weld areas or in press fitting connections. These cases are discussed with the objective of identifying key parameters, suggest possible mechanisms and discuss whether prediction is possible.