Cal. No. 151, Docket 83-4045. Argued September 19, 1983. Decided January 31, 1984. Charles P. Donnelly, Washington, D.C. (William Wachter, William A. Lubbers, Gen. Counsel, John E. Higgins, Jr., Deputy Gen. Counsel, Robert E. Allen, Assoc. Gen. Counsel and Elliott Moore, Deputy Assoc. Gen. Counsel, Wash., D.C., on the brief), for petitioner. Robert C. Cohen, Philadelphia, Pa. (Markowitz Richman, Philadelphia, Pa., of counsel), for respondent Local Union No. 46, Metallic Lathers and Reinforcing Iron