Guidelines for the Removal of Typical Unauthorized Building Works ...

(c)UBW erected on top of another UBW(i)(ii)Before the commencement of the removal of the UBW at thetop, all the occupants of the UBW below must be evacuated.Staff of BD will be able to assist where necessary byobtaining a Closure Order from the courts.A contractor should take note that any excessive loadingfrom building material dismantled from the UBW at the topcould cause the UBW at the bottom to collapse. Therefore,any building material or debris from the removal worksshould be put into bags and lowered to ground level as soonas they are dismantled.(iii) Similar methods of demolition and safety measures, as forthe removal of UBW over service lane provided aboveshould be followed.(iv) In addition, a double scaffolding should be provided aroundthe external perimeter of the UBW to be removed to providea working platform for the workers and as a protectivemeasure against the accidental falling of any small debris asindicated in fig 4.(d) Rooftop and flat roof structures(i) Before the commencement of any removal works, theexternal perimeter of the structures should be enclosed bydouble scaffolding to provide a working platform and toprevent the accidental falling of any small debris asindicated in fig 4.(ii) Where the UBW is adjacent to the external walls of the mainbuilding, a catchfan should be erected to protect the fallingoff of any small debris from the demolition works. Catchfanshall be installed at a vertical distance of not more than 10mbelow the working platform. A typical detail of suchcatchfan is provided in fig 5.(iii)The sequence of demolition should generally follow thosefor lane structures.(iv) Therefore, any debris from the demolition work should beput into small bags and transported through the mainbuilding to ground level as soon as they are removed fromthe UBW.(v)Any excessive loading could cause a danger to the mainbuilding.