117. Warning signs, barricades, etc.- The employer shall ensure at a construction site of a building or other construction work that,- (a) barricades and warning signs are erected along every side throughout the length and breadth of a building or other construction work to be demolished to prevent unauthorised persons from entering into the site of such building or other construction work during demolition operations; (b) during the demolition of an exterior masonry wall or a roof from a point more than twelve metres above the adjoining ground level of such wall or roof, if persons below such wall or roof are exposed to falling objects, suitable and safe catch platforms shall be provided and maintained at a level not more than six metres below the working level except where an exterior built-up scaffold is provided for safe and adequate protection of such persons; (c) suitable and standard warning signs in accordance with national standards are displayed or erected at conspicuous places or position at the workplace. | 
