OSHA Safety and Health Regulations for Construction (29 CFR Part 1926) 1926.850: 1926.850 Preparatory operations

Before employees begin demolition, a competent person must carry out an engineering survey of the structure to assess the condition of framing, floors and walls and the chance of unplanned collapse of any part, and adjacent structures where employees may be exposed must be checked the same way. The employer must hold written evidence that the survey was done. Where employees must work inside a structure that fire, flood, explosion or another cause has damaged, walls or floors must be shored or braced. Before demolition starts, all service lines (electric, gas, water, steam, sewer and others) must be shut off, capped or controlled in some other way beyond the building line, with advance notice to any utility company involved; utilities that must stay in service are temporarily relocated as needed and protected. The employer must find out whether any pipes, tanks or other site equipment have held hazardous chemicals, gases, explosives, flammables or comparable substances; where they are apparent or suspected, testing and purging must eliminate the hazard before demolition. Glass fragmentation hazards must be removed. Wall openings that employees could fall through must be protected to about 42 inches high. Where debris is dropped through floor holes without chutes, the landing area must be fully enclosed by barricades at least 42 inches high set 6 feet or more back from where the edge of the opening above projects down, warning signs posted at each level, and no removal done below until dropping stops above. Floor openings not used for drops must be covered with secured material strong enough for any imposed load. Apart from cutting chute and drop holes, preparing storage space and similar preparatory work, exterior walls and floors are demolished from the top down, each story removed and dropped to storage before the story below is started. Employee entrances to multi-story structures under demolition must be fully protected by canopies or sidewalk sheds, or both, extending at least 8 feet from the building face, wider than the entrance by at least 2 feet (1 foot each side) and able to carry 150 pounds per square foot.