§ 33.301. General requirements.

 (a)  Lighting. Sufficient light, either natural or artificial, shall be provided at all times in all excavation operations where men are at work or where they pass to and from their work.

 (b)  Pick and shovel men. Pick and shovel men working in excavations shall be required by the contractor or the contractor doing the excavation work to be a sufficient distance apart to prevent injury to one another.

 (c)  Ladders. All excavations shall at all times be supplied with at least one ladder for each 100 feet in length or fraction thereof. The ladder shall extend from the bottom of the excavation to at least 3 feet above the surface of the ground.

 (d)  Warning lights. Red lanterns, torches or amber lights shall be placed along the exposed sides of all excavations at night as required for necessary warning to the public.

 (e)  Guardrails. Guardrailings or barricades shall be provided at or near the sides of excavations as necessary to protect the workmen and the public.

 (f)  Bracing. The sides of all excavations where the earth is not sloped the angle of slope, shall be securely held by adequate bracing. The bracing shall be carried along with the excavation and shall in no case be omitted unless the excavation is cut in solid rock or hard shale. If a mechanical digger is used, the bracing shall be placed as close as possible at a maximum of 6 feet if physically possible to the lower end of the bucket. The bracing shall be held in place by screw jacks or by cross braces cleated and wedged in place. Where the width of the excavation prevents this, the lower end of the cross brace shall bear against a footing in the earth at the bottom of the excavation if adequate means are taken to keep it from kicking out. Braces shall be considered as columns or struts and shall be of adequate dimension for stiffness.

 (g)  Timbering. When the sloping of excavations to the angle of slope does not extend to the bottom of the excavation, the timbering shall be as required to support the vertical part of the excavation. The sheeting shall extend not less than 12 inches above the bottom of the slope, and, if necessary, toeboards shall be placed behind the timbering to prevent material from sliding into the excavation. The surface of the slope shall be cleaned of boulders, stumps, or other hard masses of earth to eliminate the danger of their sliding into the excavation.

 (h)  Excavated material. Excavated material and superimposed loads shall not be placed nearer than 18 inches from the sides of the excavation unless bracing has been installed and designed to withstand the load.

 (i)  Undercutting. When excavations are undercut, they shall be shored to safely support the overhanging material.

 (j)  Underpinning. If an excavation is cut alongside an existing structure and the footings of the structure are nearer to the excavation than the plane of repose for the soil, they shall be underpinned or the side wall of the excavation rigidly supported.

 (k)  Distance between stringers. Considering the planks used for sheet piling as beams to support the load imposed by the lateral earth pressure, the maximum allowable distance between the horizontal stringers or wales shall be such as will keep the planks within their safe bending stress.

 (l)  Cleats. In excavations, cleats shall be spiked or holted to join the ends of braces to stringers to prevent the braces from being knocked out of place. Cleats bolted shall have a minimum nominal thickness of 1 inch and shall be the same width as the cross braces to which they are fastened. The size of bolts shall be 1/4 inch minimum diameter. At least two bolts shall be used to secure each cleat to the cross brace. When cross braces are 6 inches by 6 inches or larger in cross section, the cleats shall have a minimum thickness of 2 inches and size of bolts shall be three eighths of an inch minimum diameter.

 (m)  Sheet piling. When the depth of the excavation requires two lengths of sheet piling, one above the other, the lower length shall be set inside the bottom stringers or wales of the upper length and driven down and braced as the excavation continues.