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 conducting 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.