What is classed as a demolition work?

A demolition work is any kind of work that involves the complete dismantling of a structure or part of a structure. The structure can either be temporary or permanent, immovable or moveable like towers, storage tanks, sheds, buildings, storage towers and chimney stacks. When demolishing an element of a structure that is load bearing, it will be labeled as ‘high risk construction work’. When the demolition work involves high-risk construction work, you must prepare a Safe Work Method Statement.

Demolition work that requires a report under the WHS Regulation include:

  • Demolition of any part of a building that supports the weight of other parts of the structure or is a fundamental part of the building’s core.
  • Demolition work that involves the use of explosives
  • Demolition work that consists of load shifting equipment on a suspended floor
  • Structure that has reached 6 metres high

What differentiates demolition from deconstruction is that in deconstruction, it tears the building down but it preserves important elements that can be repurposed. Demolition work does not include the tearing down of false work; formwork, scaffolding or any other structure used to provide access, support or storage during the course of construction work. Furthermore, demolition is not involved in the removal of telecommunication poles, lights and power.

The demolition process is much simpler for small structures like houses that consist of a maximum of three stories. The man-made structure is flattened either manually or mechanically through the use of sizable hydraulic equipment such as bulldozers, excavators and cranes. Meanwhile, for larger structures, a wrecking ball may be required. A wrecking ball is a heavy ball made of metal that is swung by a crane to hit a building for the purpose of demolishing it. Wrecking balls are highly effective when used against stonework but it has a couple of disadvantages. One, wrecking balls are difficult to control and two; they are less effective compared to modern methods. Today, the latest methods make use of rotating hydraulic shears as well as silenced rock-breakers that are affixed to excavators to penetrate through concrete, steel and wood.

Make sure you comply all the needed requirements before you start the demolition work.

WHAT ARE THE HAZARDS OF DEMOLITION WORK?

Demolition work has its own fair share of hazards. Identifying what these are can help manage the risks. The following are potential hazards of demolition work:
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  • Unexpected collapse of the structure
  • Exposure to silica or asbestos
  • Falling debris
  • Falls from one level to another
  • Being exposed to toxic chemicals that may be present in the ground or that could reek from the demolished materials
  • The nearness of the building being demolished to other buildings
  • Location of above and underground services such as telecommunications, sewerage, water, gas, fuel lines, refrigerant in pipes, electricity and chemicals
  • Hazardous noise as a result of explosives and plant used to carry out demolition work

HOW DO YOU ASSESS THE RISKS?

After you have identified the hazards, your next step is to perform a thorough risk assessment. A risk assessment is crucial to help you establish the control measures you are going to use to reduce the risk of potential hazards. This is a requirement when you are working with explosives and/or asbestos.

When evaluating the risks involved in demolition work, you should take into account the following:

  • The structure and the structural integrity of the building that is about to be demolished
  • The demolition technique being used as well as its order
  • The schedule of work
  • The skills and experience of the workers who will be performing the demolition work
  • The possible exposers that might happen
  • The blueprint of the site
  • The plant and equipment to be used during the demolition work
  • How many people will be involved
  • The weather

HOW DO YOU CONTROL THE RISKS?

Control measures for demolition hazards must have a ranking. The ranking must be from the highest reliability and protection to the lowest. The said ranking is commonly known as the hierarchy of control.

You should strive to remove the hazard but if this is not feasible then you should at least reduce the risk by one or a combination of the following:

  • Head Office Address
    if according to your assessment a manual method is safer compared to a mechanical method of demolition then you can choose to substitute it for a safer technique.
  • Isolation
    an example of isolation is making use of concrete barriers to protect pedestrians or the use of mobile plant operators to minimise the probability of collisions.
  • Engineering controls
    an example is using a falling objects protective structure on an open cab excavator to minimise the risk of getting hit by falling debris.

If the risks are still present despite the use of substitution, isolation and engineering controls, then it’s time to proceed with administrative controls. Some examples include putting up warning signs and establishing exclusion zones surrounding the demolition site. Using suitable personal protective equipment or PPE can reduce other remaining risks. Examples of personal protective equipment include steep cap boots, hard hats and high visibility vests.

PPE and administrative control measures mostly depend on command and human behavior and are deemed less effective when it comes to reducing risks.

There are several factors you need to consider when selecting appropriate control measures. These are the following:

  • Plant and equipment items
    large structures need scaffolding or a powered mobile plant to be able to work on suspended floors
  • Storage arrangements at the site
    for instance, the location of the dismantled materials to manage dust
  • Mobilisation of demolished material
    the nature of the haul route, the duration of the travel, the access to the workplace and the load-shifting equipment utilised

What are the legal requirements prior to the commencement of a demolition work?

A person conducting a business or undertaking (PCBU) must obtain a demolition work licence as required by the Workplace Health and Safety Regulation.

There are specific legal requirements needed before demolition work:

1. OBTAIN A NOTICE OF DEMOLITION WORK – WHS REGULATION 2011, S142 (1) AND (2)

A person conducting a business or undertaking (PCBU) that intends to pursue the following types of demolition work must present a written notice to Workplace Health and Safety Queensland at least five days before the work begins.

  • Unexpected collapse of the structure
  • Exposure to silica or asbestos
  • Exposure to silica or asbestos

The notice must be done using Form 65: Notification of licensed asbestos removal work, demolition work or emergency demolition.

2. OBTAIN A NOTICE DEMOLITION WORK BY AN EMERGENCY SERVICE ORGANISATION – WHS REGULATION 2011, S142 (2), (3), (4)

All emergency service organisations must provide a notice of demolition work (s142 (2), (3) and (4) as soon as possible. It can be done before or after the demolition work is carried out, when the demolition work is carried out while providing first aid to a person.

The notice must be done using Form 65: Notification of licensed asbestos removal work, demolition work or emergency demolition.

3. MUST HAVE A LICENCE TO CARRY OUT DEMOLITION WORK – WHS REGULATION 2011, S143

A PCBU or a direct worker must not be allowed to carry out demolition work unless they are licensed to perform demolition work.

4. NOMINATED COMPETENT PERSON MUST BE AVAILABLE AND PRESENT DURING DEMOLITION WORK – WHS REGULATION

Whoever is nominated under a demolition licence must be present to supervise the workers who will carry out the demolition work.

5. TRAINING FOR WORKERS – WHS REGULATION 2011, S144(2)

The PCBU that holds the licence to perform the demolition work must train the workers to ensure that the demolition work is done proficiently and safely.

6. CONSTRUCTION WORK – WHS REGULATION 2011 CHAPTER 6 CONSTRUCTION WORK

Under WHS Regulation, demolition work is regarded as construction work therefore it must be carried out in compliance with the strict regulations.

7. SAFE WORK METHOD STATEMENTS – WHS REGULATION 2011, S291 AND S299

The safe work method statements are strictly necessary for all high risk construction work.

8. NOTIFIABLE INCIDENTS – WORK HEALTH AND SAFETY ACT 2011, S35, S36, S37, S38 AND S39

Complete or partial collapse of a building is considered a dangerous incident. It is imperative that you notify the Workplace Health and Safety Queensland right away.

What are the legal requirements prior to the commencement of a demolition work?

A person conducting a business or undertaking (PCBU) must obtain a demolition work licence as required by the Workplace Health and Safety Regulation.

There are specific legal requirements needed before demolition work:

  • The first step is to complete Form 76 – Application for a licence to carry out demolition work. Make sure you attach all the necessary documents required.
  • Submit all the documents together with Form 76 to Workplace Health and Safety Queensland. You will be required to pay a fee.
  • The WSHQ will get in touch with you if additional information is needed.
  • If your request is approved, the WHSQ will issue the licence to the PCBU.
  • Followed by the issuance of the licence to the business.

What are the safety precautions before and during demolition?

A person conducting a business or undertaking (PCBU) must obtain a demolition work licence as required by the Workplace Health and Safety Regulation.

There are specific legal requirements needed before demolition work:

  • Safety precautions are necessary in compliance with AS2601-2001, The Demolition of Structures’
  • The demolition work will not be allowed to push through unless all precautionary measures have been checked and approved. It is also required to inform nearby neighbors about the demolition work so they too can take measures like closing their doors and windows.
  • All apparatus that could be a source of danger and all electric cables must be disconnected before and during the demolition work.
  • A skilled foreman must be present to provide supervision while the demolition work is ongoing.
  • Demolition should be done storey-by-storey starting at the roof and working its way downward unless otherwise indicated.
  • All precautions must be taken to prevent danger from the collapse of a building.
  • A professional asbestos removalist registered by the Victorian Work Cover Authority must remove all traces of asbestos at the demolition site in compliance with the Occupational Health and Safety Asbestos Regulations in 2003.
  • If the demolition site borders a public walkway or a street, it is required to erect a hoarding that is 2.4 metres high on the boundary. A notice should be in place in compliance with AS1319 showing the words “WARNING DEMOLITION IN PROGRESS” and should be fixed to the security fence or the hoarding.
  • If the demolition site borders a public street or a walkway, apart from hoarding, the walkway has to be roofed by an overhead protective structure or a canopy unless the height above the walkway is below four metres.
  • Materials that result from the demolition must not be allowed to stay on the floor or the structure if its weight is more than the safe carrying capacity of the structure or floor. These materials have to be carefully and properly stacked or piled so as not to endanger the workers or any other person for that matter. All materials should be removed right away unless otherwise ordered by a Building Surveyor.
  • Materials that create dust should be completely dampened and should not be dropped or thrown from the building. It should be lowered using a hoisting equipment or through material chutes.
  • Chutes should be enclosed completely with a danger sign strategically placed at the discharge end of each chute.
  • Not any part of the external wall or within a 3-metre radius of a street alignment is allowed to be pulled down not unless during the hours of 7:00 AM until 6PM on weekends and public holidays unless authorised by a Building Surveyor.
  • No chimney, wall or any other structure or part of a structure should be left unsupported or unattended as it might potentially collapse as a result of vibration or wind since it can be very dangerous. You should install protective outriggers to places necessary to prevent danger.
  • Once the demolition work has been completed, you should provide a notification to the Building Surveyor that the demolition project has been satisfactorily completed
  • No leveling of the site or bulk excavation forms part of the demolition permit.
  • Demolition work should not be allowed at night or during a heavy rain or storm. If however, it requires to be done at night, you should install glaring red warning signals, working lights, sirens and provide watchmen. It is also necessary to install auditory warning devices at the demolition site. The workmen must be equipped with safely belts, boots, gloves, helmets and goggles that are made of celluloid lenses.