5. DEMOLITION METHODS
Roof access The person conducting a business or undertaking where persons are employed to work on roofs has a responsibility to ensure that the access from the ground to the actual work area is safe and without risk to health. Access arrangements may include personnel hoists, scaffolding, temporary work platforms and ladders.
Purlin trolleys Purlin trolleys are plant designed to travel on top of purlins( horizontal beams running along the length of a roof) and can be used to support material and roof workers. They are sometimes used during the removal of roof coverings.
Purlin trolleys should be provided with a holding brake and a device to prevent their accidental dislodgment from the supporting purlins. Where it is intended that the roof workers be supported by the trolley, the trolley should be provided with suitable safety harness anchorage points.
Before a purlin trolley is placed on a roof structure:
• a competent person( e. g. a structural engineer) should have considered whether the roof structure is suitable for the particular purlin trolley and its operational loads
• the purlin trolley should be designed and constructed to withstand the loads placed on it and for the purpose of the safe movement of materials and / or persons across the roof surface.
MANUAL DEMOLITION OF WALLS Glass should be removed from the windows, doors or openings before the commencement of the demolition work.
Walls and gables should be demolished course by course. All work should be performed from safe working platforms. Workers should not work from the top of a wall or partition being demolished. A wall or partition should not be permitted to stand, unless it is effectively supported against collapse, including being supported against lateral loads from wind and other forces.
If the demolition work involves the demolishing course by course of any walls, columns, piers or other vertical structural members, the demolition contractor should check that:
• risks to persons and property from falling collapsing and rebounding material are eliminated or minimised
• the remaining portion of the building or structure, if any, can withstand any loads, impacts and vibration caused by felling or other environmental factors such as wind.
MANUAL DEMOLITION OF FLOORS AND MEMBERS All floors and other surfaces used to support workers, plant, equipment or materials should be assessed as capable of supporting the load. Suspended floors and their supporting members should not be loaded by workers, plant, falling or accumulated debris / materials to the extent that there is excessive deflection, permanent deformation or danger of collapse. If water is used, the increased weight of the watered debris should be taken into account. For further information refer to AS 2601: The demolition of structures.
Openings in floors, through which a person may fall, shall be properly guarded or boarded over and the boarding secured against accidental removal. Any covers or boarding of openings in floors should be of sufficient strength to withstand any expected loads that may be imposed on the floor, for example elevating work platforms, people and material. Drop zones should be isolated and / or guarded to protect workers and the public from falling objects.
CODE OF PRACTICE | DEMOLITION WORK 27