Section 1926.856 - Removal of walls, floors, and material with equipment(a) Mechanical equipment shall not be used on floors or working surfaces unless such floors or surfaces are of sufficient strength to support the imposed load.(b) Floor openings shall have curbs or stop-logs to prevent equipment from running over the edge.(c)Cranes, derricks, and other mechanical equipment. Employers must meet the requirements specified in subparts N, O, and CC of this part.44 FR 8577, Feb. 9, 1979 , 75 FR 48135, Aug. 9, 2010; 77 FR 49730, Aug. 17, 2012; 78 FR 23843, Apr. 23, 2013