As structures approach the end of their design life, they need to be removed entirely, or in some cases partially remodelled or repurposed to better serve their owners. In many ageing structures, asbestos-containing materials (ACMs) are commonplace. In such instances, it is critical to ensure that the removal and disposal processes and procedures associated with handling ACMs are strictly adhered to. These materials range from insulation to ceilings, fascias, windowsills and even floor tiles.
“Due to the nature of our works, we encounter hazardous materials on the vast majority of our sites,” explains Jet Demolition Contracts and Project Manager Kate Bester. In heavy industry, it is not uncommon to have significant hydrocarbon spills, for example, that impact on surface slabs, or oily water within oil-separators. However, asbestos is slowly becoming less commonplace, as there is a greater focus on replacing ACMs with environment-friendly alternatives as structures age.
Jet Demolition is approved by the Department of Labour as a registered asbestos contractor, capable of undertaking asbestos works across three defined classes in terms of the asbestos regulations as updated in 2020. Removal is carried out by registered asbestos contractors, while compliance monitoring and safe disposal are undertaken by dedicated, independent specialist service providers.
The method of removal and disposal requirements depends on the directives issued by the independent authorised inspection authority. A plan of works outlines the exact precautions and requirements for the safe removal of ACMs. It might include directives in terms of wet or dry removal, encapsulation, or even the erection of weather shields, and is a result of a dedicated risk assessment process.
In terms of demolition rubble in general, this can be considered a valuable commodity rather than a waste by-product. In most instances, demolition rubble is transported to registered disposal sites where it is used to rehabilitate landfills or provide stormwater protection. “In other instances, we are able to crush the rubble, liberating rebar for recycling, and reusing the crushed material in engineered fills,” explains Bester.
Waste handling is governed by the National Environmental Management Act. “We have a responsibility to ensure that any hazardous waste we come across is suitably managed and handled appropriately,” says Bester. Both client and contractor need to be aligned in terms of what waste can be anticipated, how this waste will be handled, and ensure strict adherence to all relevant legislation. This includes cradle-to-grave reporting and the submission of waste disposal receipts for full accountability throughout the project.
The equipment deployed to waste-handling activities depends on the method, quantity, location, and the nature of the waste. For example, asbestos stripping and removal is mainly done by hand, whereas removing hydrocarbon impacted concrete might be removed using a grinding wheel affixed to a specialised excavator. A demolition excavator equipped with a shear can demolish contaminated steel, supplemented by hand-held ultra-high pressure washing, and finally handled by excavators equipped with demolition grapples.