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