This Technical Specification specifies a procedure for carrying out impressed current electrochemical chloride extraction from chloride bearing concrete in existing structures. It is applicable to atmospherically exposed parts of structures with ordinary reinforcement and/ or post-tensioned tendon ducts embedded in concrete. In the latter case, it is essential to verify that there is no risk of hydrogen embrittlement, if necessary by conduct-ing trials and installing monitoring during the treatment. This Technical Specification does not apply to pretensioned concrete, which may suffer hydrogen embrittle-ment on the stressing bars during chloride extraction, or to concrete containing epoxy-coated or galvanised reinforcement.