Demolition involves the knocking down of buildings to clear ground, but it also includes smaller works in maintenance and renovation, such as the dismantling of parts of structures (e.g. one part of a steel-framed building) or the removal of walls (e.g. to create open-plan rooms). The hazards associated with demolition are very similar to those encountered in other types of building work, with a few additions.
Demolition hazards vary depending on the nature of the work, but typical hazards include:
- The premature collapse of structures.
- Work at height.
- Plant and machinery.
- Contact with live overheads.
- Contact with buried services.
- Movement of vehicles.
- Noise and vibration.
- Hazardous substances from previous use of the building.
- Biological hazards from vermin or stagnant water.
- Sharp objects, including glass and nails from the demolition, or syringes left by trespassers.
- Manual handling.
Control measures include:
- Careful assessment and planning of the work to eliminate hazards where possible, e.g. selecting a demolition method that keeps workers away from the immediate area, such as a long-reach machine or a crane and ball.
- Elimination or control of work at height.
- Structural surveys to assess the strength and stability of the structure and adjacent structures; propping and supporting may be necessary to prevent collapse.
- Assessing the strength and stability of floors to ensure that plant, machinery, and debris put on those floors do not exceed their tolerance.
- Disconnection of services (e.g. gas, electricity, water).
- Removal and disposal of any hazardous materials, such as asbestos, prior to demolition.
- Securing the site with fencing or hoardings to create a buffer zone and exclude unauthorized people.
- Damping down with water spray to reduce dust creation.