Overview
Demolition is one of the most hazardous activities in the construction industry, requiring specialist plant, trained operators and meticulous planning. This CPD module covers the operation of demolition plant, with particular focus on high-reach demolition machines, structural assessment requirements, the establishment of exclusion zones and the management of hazardous materials including asbestos. Demolition work in the UK is governed by BS 6187 and must be carried out under the supervision of a competent person with appropriate experience and qualifications.
Key Knowledge Areas
High-Reach Demolition Machines
High-reach excavators fitted with specialist demolition attachments (crushers, shears, pulverisers) are the primary plant used for demolishing multi-storey structures. Operators must understand the machine’s maximum reach, working load at height, and the effects of attachment weight on stability. Ground bearing capacity must be verified, as high-reach machines exert significant point loads through their tracks. The operator must maintain awareness of the structure’s behaviour during demolition, watching for signs of unplanned collapse or instability.
Structural Assessment and Sequencing
Before demolition commences, a structural survey must be carried out to identify load-bearing elements, pre-stressed or post-tensioned concrete, shared walls and connections to adjacent structures. The demolition sequence must be planned to ensure controlled, progressive removal of the structure from top to bottom (or as specified in the method statement). The sequence must prevent premature collapse and ensure that the structure remains stable at all stages of the demolition process.
Exclusion Zones
Exclusion zones must be established around the demolition area to protect workers and the public from falling debris, dust and noise. The size of the exclusion zone depends on the height of the structure, the method of demolition and the surrounding environment. Physical barriers, signage and banksmen must be used to enforce exclusion zones. Where demolition takes place adjacent to live highways or occupied buildings, additional protection measures such as debris netting, fans and hoardings may be required.
Asbestos Awareness
Many structures scheduled for demolition contain asbestos-containing materials (ACMs), particularly those built before 2000. A refurbishment and demolition (R&D) asbestos survey must be carried out before any demolition work begins. Licensed contractors must remove all identified ACMs before the main demolition works commence. Operators must understand the types of asbestos, where they are commonly found, and the procedures to follow if unexpected ACMs are encountered during demolition — including stopping work immediately and reporting to the site manager.
Dust Suppression and Environmental Controls
Demolition generates significant quantities of dust, which may contain silica, lead, asbestos fibres and other harmful substances. Water suppression systems must be used on all demolition plant, and additional measures such as mist cannons, damping down and sheeting may be required. Noise and vibration must be controlled in accordance with BS 5228, and waste materials must be segregated and disposed of in compliance with waste management regulations.
Safety Considerations
All demolition plant must undergo daily pre-use checks covering structural integrity of booms and attachments, hydraulic systems, safety devices and operator protection (FOPS/ROPS). Operators must wear full PPE including hard hat, high-visibility clothing, dust mask and hearing protection as appropriate. Emergency procedures must be in place for unplanned collapse, fire and the discovery of hazardous materials. Communication between the operator, banksmen and the demolition supervisor must be maintained at all times, and work must cease immediately if conditions change or an unsafe situation develops.
Exam Tip: Demolition questions frequently focus on the correct sequence of operations, exclusion zone requirements and asbestos awareness. Remember that a refurbishment and demolition asbestos survey is mandatory before demolition begins, and that all ACMs must be removed by licensed contractors before main works proceed. Understand the specific hazards of high-reach machines, including stability and ground bearing requirements.
