Cases
A number of practical experiences from failures in Finland and Denmark [10-12] have been collected to give an insight into the phenomena. In all the cases given here the material quality was as specified and the press fittings were correctly assembled. In some cases with welded connections, however, these were not of good quality. The microbiological data available are very limited, as these cases are often a matter of controlling whether the material quality and the installations were correct according to specifications. In the expert consensus on MIC by NACE International TG 304 in 2004 [13], good advice is given on the failure analysis and diagnosis stating a variety of techniques. To thoroughly evaluate the failure both metallurgical and microbiological data must be combined and ideally trends in chemical and microbiological data included. In these cases the specific mechanism has not been documented, but a number of parameters common in the cases can be acknowledged.