5. DEMOLITION METHODS
The sequence in which a building or other structure is demolished can be critical for the health and safety of workers and the general public.
The demolition sequence will depend on things like the type of construction, location, and demolition method( s) selected. Buildings and structures should generally be demolished in reverse order to their construction, that is, by‘ sequential demolition’. In particular:
• sequential demolition should be carried out in reasonably even stages, commencing from the roof or top of the building or structure being demolished
• multi-storey buildings or structures should be demolished storey by storey
• masonry and brickwork should be taken down in reasonably even courses.
There is a range of demolition methods that may be used, either separately or in combination. Control measures should be selected on the basis of the demolition method( s) used. However, no matter what method is used, the building or structure to be demolished and all its components should be maintained in a safe and stable condition so as to prevent the unexpected collapse of part or all the structure. Temporary braces, propping, shoring, or guys may need to be added for stability.
Further information on demolition methods can be found in AS 2601: The demolition of structures.
5.1 Manual demolition
Manual demolition includes any technique where hand tools such as jackhammers, sledge hammers and picks are used.
Manual demolition has many of the hazards that are present in other major demolition activities including unexpected collapse, falls, falling objects, manual handling and exposure to noise, dust and hazardous chemicals.
To manage the risk of unplanned collapses, the condition of roofs, walls and floors of the building should be assessed by a competent person before commencing demolition work.
Where concrete members are being demolished manually, the reinforcement shall not be cut while breaking of the concrete is in progress.
Where pre and post-tension demolition work is undertaken competent person advice should be sought as to demolition sequence. More information on the demolition of pre and posttensioned concrete is at Section 6.1 of this Code.
Areas where debris will fall should be barricaded off and signs erected to prevent persons from entering before demolition starts.
MANUAL DEMOLITION OF ROOFS Controlling the risk of falls of persons or objects is an important consideration for roof work.
Where it is not reasonably practicable to demolish a roof using mechanical means or to remove the roofing from work platforms below the roof, then careful consideration should be given to the most suitable method of protection for workers engaged in the removal of the roofing. For example, roof trusses should be removed using safe temporary work platforms. It is important to ensure that the removal of trusses does not cause wall instability.
CODE OF PRACTICE | DEMOLITION WORK 25