Demolition Safety and Planning

About this course.

Demolition is high-risk because it deliberately removes strength from a structure and brings it down, and doing so can release a wide range of serious hazards: uncontrolled or premature collapse, falls from height and into voids, striking by falling material and plant, the disturbance of hidden hazardous materials such as asbestos and lead, contact with live services, and danger to the public and neighbouring buildings. Under Australia's model WHS framework, the person conducting the business or undertaking (PCBU) that carries out or commissions the work holds primary duties to ensure health and safety so far as is reasonably practicable, and the person who plans and commissions the demolition has a duty to plan it properly, engage competent people, provide the information they need, and allow adequate time and resources to do the work safely.

The fundamental reason demolition is dangerous is that it inverts the logic of construction. In building, elements are added and the structure becomes progressively stronger and more stable; in demolition, elements are removed and the structure becomes progressively weaker and less stable, often in ways that are not obvious. A building is an interconnected system in which loads flow through beams, columns, walls, floors and connections along paths that may not be documented and may have changed over the building's life through alterations, additions and deterioration. Removing an element can redistribute loads onto parts that were never intended to carry them, and can remove the very bracing or restraint that was keeping another part stable. Unless the sequence of removal is planned so that stability is maintained at every step, the structure can collapse in an uncontrolled and unexpected way.