Fences shall entirely enclose the construction/demolition site and shall be erected on the building side of sidewalks or walkways and shall be made of approved materials (e.g. G.I. sheet, wooden boards and/or planks, plywood or Lawanit, sawali), not less than 2.40 meters in height above the curb line. Fences shall be built solid for its full length except for such openings as may be necessary for proper execution of the work. Such openings shall be provided with doors, which shall be kept closed at all times except when in actual use.