These recommendations apply to cement lining of steel pipe and tubing used for shielding the steel from chemical corrosive attack encountered in the handling of oil filed brines. This recommended practice suggests minimum requirements and should in no way be interpreted as a restriction on the use of other procedures or materials. Neither is this recommended practice intended to apply in all cases relating to the subject. Environment may negate the usefulness of cement linings in specific instances. Cement Lining and Cement Lined as used in this recommended practice refer to the cement-mix proportions as set forth in Section 3@ Par. 3.2.a.