51.91Where a portable ground ladder is used for structural fire-fighting, an employer shall ensure that it meets or exceeds NFPA 1931, “Standard on Design of and Design Verification Tests for Fire Department Ground” Ladders, 1994 edition, and is used, maintained and tested in accordance with NFPA 1932, “Standard on Use, Maintenance and Service Testing of Fire Department Ground Ladders”, 1994 edition.