The South African construction industry is under enormous pressure due to reduced margins and rising costs, especially given the impact of the Covid-19 pandemic on the future project pipeline. While detailed planning for new construction projects is fairly common, the same level of care is often not applied to the demolition phases, notes Jet Demolition contracts manager, Kate Bester (NDip Civil Engineering).

The expectation is to conclude demolition quickly and cheaply, without much regard for the end use of the demolished materials. Achieving a fully-compliant site is perceived as an ideal only achievable at a significant cost. However, Green Star certifications are possible with a well-planned and carefully thought-out approach.

In many cases, clients requesting green-rated buildings prompt consultants and architects to consider alternative construction methods, processes and designs to accomplish these ratings. Different types of ratings hold different requirements, but in general, green buildings have requirements
for more environmentally-friendly methods and building materials.

This may include things like designing for LED lighting, recycling of grey water, harvesting of rainwater and making use of more glass to reduce the need for artificial lighting etc. One major aspect of achieving green ratings is waste reduction. Typically, this generally refers to waste generated once a building is occupied, but it can also be taken into consideration prior to a building being constructed. This is where a demolition specialist like Jet Demolition comes into play.

Confined space demolition within a live facility.

“As you know, South Africa only recently [relative to international standards] started embracing a green rating system. This means that very few technologies exist within the demolition environment to assist clients in achieving their Green Star goals at reasonable and acceptable rates,” comments Bester.

RUBBLE REUSE & WASTE MANAGEMENT

“I believe that, as there is an increased need and requirement for turnkey Green Star projects, more opportunities will become available to the demolition contractor. As an example, most inert demolition rubble such as concrete and brick can readily be crushed and reused for future building works,” highlights Bester.

Downsizing of demolished concrete for in situ rehabilitation.

Demolition rubble can, in certain instances, be used in road layerworks to create compacted platforms or even used in site rehabilitation, landscaping and stormwater management. Unfortunately, the cost of preparing this material and converting it from a waste into a reusable resource is often prohibitive and not suitably anticipated or prepared for at the inception stage of a project.

However, Bester points out that there are conditions that may not require such stringent gradings that allow for this material to be used to the benefit of a wide range of potential recipients. For example, local farmers often welcome the material to assist in managing stormwater flow or may even request a finely crushed material for use on their road networks. In general, all steel recovered from large-scale demolition projects can be recycled. In addition, recovered trusses or doors may be recycled, mulched or simply reused.

“There is massive potential for the recycling of the vast majority of materials that result from large demolition works. The only exception is the very few hazardous materials that simply cannot safely be reused or recycled,” stresses Bester.

Therefore, waste management is a critical component of any large-scale construction or demolition project. It is vital that clients, engineers and contractors communicate clearly prior to the commencement of a project in order to ensure alignment across all spheres. This ensures a co-operative and collaborative approach to projects, with different people actively seeking practical, cost-effective and responsible solutions to very basic problems.

It is essential that all role-players become involved at the beginning of a project, which can be achieved by determining what the thresholds are and then seeking alternative solutions that can meet these thresholds while still being cost-sensitive.

Removal of asbestos cement cladding.

DEALING WITH HAZARDOUS MATERIALS

The vast majority of construction materials are able to be sorted and cleaned mechanically either prior to or during demolition activities. Hazardous material abatement is crucial in order to remove the potential risk and contaminants from a structure prior to demolition, thereby resulting in ‘clean’ rubble from a structure.

While general hazardous materials are mostly prevalent in industrial, chemical and mining plants, asbestos-containing material is present across the board from ceilings to insulation wool, fascias, piping, floor tiles and window sills. “There is no specific industrial sphere where there is a greater prevalence. The older the facility, the more likely and more common asbestos is,” adds Bester.

Jet Demolition offers asbestos abatement, which is often associated with the demolition of older structures. The company is registered with the Department of Labour as an asbestos contractor and is certified to safely remove all types of asbestos in strict accordance with the relevant regulations and standards, such as the Asbestos Regulations (Regulation 155 of 2002), Environmental Laws Amendment Act 14 of 2009 and Waste Act 59 of 2008.

Personnel are fully trained and experienced to identify and handle asbestos, including asbestos-contaminated materials. They work closely with independent occupational hygienists to develop a comprehensive asbestos plan of work, and to carry out compliance and air monitoring throughout the course of the project.

Specialised PPE is required to undertake the work, as well as method-specific equipment such as HEPA filter vacuum cleaners. Both dry and wet removal and encapsulation techniques are deployed, thereby limiting the spread of asbestos fibres.

Site safety is always of paramount concern, adds Bester. Jet Demolition typically abates hazardous materials prior to demolition, where practical, and then moves on to the mechanical separation of materials during demolition. Here steel is set aside and processed for delivery to a foundry for recycling. ‘Clean’ demolition rubble is used where possible as on-site layerworks or to backfill voids, and any excess material is loaded and hauled for reuse.

DEMOLITION MATERIAL TO LANDFILL

While there is no denying that a large proportion of demolition and construction rubble does go to registered landfill sites, it is critical to note that this material is often used to rehabilitate the landfill sites themselves. In this regard, the vast majority of registered landfill sites have very strict controls over the quality and quantum of material they are able to accept.

There is usually a strict grading in terms of the size limitation of the material accepted, with most material crushed prior to delivery. This material itself can then be used to cap the site or even as an engineered fill that serves as a permeable drainage layer.

In the event that there is material that cannot be suitably downsized or cleaned prior to disposal, the surcharge on the disposal is generally very high. This is specifically done to discourage the disposal of material that could otherwise have been recycled.

The fact that ‘clean’ material goes to landfill should not necessarily result in it being classified as waste. “What may be needed is a reclassification of the different waste materials,” notes Bester. The vast majority of this material is being reused and recycled, albeit through a landfill facility for capping, erosion control by farmers or backfilling sinkholes by local councils.

“I look forward to South Africa progressing to a point where demolition waste management becomes a requirement, and to working with clients to find suitable, affordable and responsible
approaches to their demolition waste management,” concludes Bester.