Hydrogen permeation measurement by the collection method enables rapid detection of hydrogen emanation (efflux) from most carbon steel surfaces liable to be encountered in petrochemical production. In this paper the case is advanced for correlation of efflux data with corrosion rates, by conversion of data to an inferred hydrogen activity at the
corroding face, ao, a parameter that is probably the best indicator of corrosive activity, independent of wall thickness and steel quality. This is used in evaluation of field data. Initial use of the hydrogen collection method has suggested widespread passivation of corrosion in cold sour systems, such that documented wall losses may occur as a result of
only occasional and intense corrosion episodes. Conversely, in hot corrosive scenarios, inhibitors and corrosive scale are less effective in preventing a long term corrosive issue. Furthermore, above about 100 °C, 300 °F it is considered that hydrogen entry into steel can occur without the presence of a hydrogen promoter such as sour gas or hydrogen
fluoride. Additionally, the permeability of steel to hydrogen increases sharply with temperature. This concurs with indications of high hydrogen permeation efflux associated with naphthenic acid corrosion.