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Counteraction of pitting in copper water pipes by bicarbonate dosing
Author(s) -
Mattsson Einar
Publication year - 1988
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.19880391104
Subject(s) - copper , metallurgy , bicarbonate , erosion corrosion of copper water tubes , chemistry , materials science , organic chemistry
Copper pipes are extensively used for tap water installations and generally perform well. Exceptionally, however, copper pipes are perforated due to pitting. Three main types of pitting (I, II and III) have been identified, but as for the causes and the mechanisms these have not yet been fully clarified. Through case studies, model experiments, thermodynamic calculations, and service tests, evidence has been obtained that waters having a pitting propensity for copper pipes can be made less corrosive by an increase of the HCO 3 −content. On water treatment the following water composition should be aimed at: – a pH value of at least 7 – an HCO 3 −content of at least 70 mg/l, preferably 100 mg/l – as low SO 4 2−content as possible, or at least lower than the HCO 3 −content (both in mg/l).