RR-F-621E, FEDERAL SPECIFICATION: FRAMES, COVERS, GRATINGS, STEPS, SUMP AND CATCH BASIN, MANHOLE (23 FEB 1989) [S/S BY A-A-60005]

RR-F-621E, FEDERAL SPECIFICATION: FRAMES, COVERS, GRATINGS, STEPS, SUMP AND CATCH BASIN, MANHOLE (23 FEB 1989) [S/S BY A-A-60005]., This specification covers manhole and catch-basis frames, gratings, steps, sumps, and catch-basins for access purposes.