Carrie LaBolle
Safety Advisor
Two of the biggest myths about demolition work are that it’s very simple and extraordinarily dangerous. The facts are very different.
First, demolition work is anything but simple. Demolishing a large structure involves a lot more than brute force, especially when other nearby structures or people have to be protected. It takes careful planning and preparation long before the actual process begins.
Second, well-planned and carefully supervised demolition may have inherent hazards, but it’s not necessarily dangerous. Again, careful planning and preparation is the key, and involving a safety professional will minimize the risks involved.
In my career, I’ve been involved with the demolition of everything from small office buildings to 175-foot stacks at industrial sites. Each project was unique, but all shared the same focus on planning and safety.
Whether you’re planning to demolish an ancient industrial facility, an outdated office building, or a structure such as a stack, the biggest issue is always the unknowns. The real hazards are usually things that you can’t see at first glance. That’s especially true with older structures, for which as-built drawings and records of renovations may not be readily available. What looks like an ordinary wall may be hiding gas pipes and electrical lines, or it may be a load-bearing portion of the structure. A locked room may be full of drums of hazardous waste; a ceiling may be lined with asbestos tiles. Even something as innocent-looking as fluorescent light bulbs may contain mercury.
That’s why the first step in a demolition project is OSHA’s requirement that a competent person conduct a thorough engineering survey of the structure to be demolished. That person doesn’t necessarily have to be an engineer – but he or she does need to have sufficient training and experience to recognize hazards and know where to find them.
In addition to identifying stray hazards such as drums and light bulbs, the purpose of the engineering survey is to locate as many potential dangers as possible. That includes checking to verify that all utility lines have been marked and can be shut off, and considering the foundation of the structure and whether it can handle the stresses involved with demolition. It also involves assessing the condition of the walls, the frames, and the floors to determine what might collapse unexpectedly during the work, and the measures that can be taken to prevent such damage.
Other factors that must be considered include past damage from flooding, fire, or high winds that could have weakened the structure. Environmental factors may affect safety, too. For example, I worked on the demolition of an old foundry, where the chemicals and processes that had been used over the years caused significant corrosion to the roofing. That made it unsafe to set foot in that portion of the building.
Of course, an engineering survey can’t find hidden hazards, so there’s always the chance that something will crop up when work begins. But an individual who is experienced with demolition can also call attention to potential hidden dangers based on the age and the nature of the structure. He or she can also evaluate the possibility of a premature collapse and which areas are most at risk.
Another key consideration is what surrounds the structure, and where the removed materials and other debris can be placed. If you’re using a crane as part of the demolition, you need to consider its swing radius and any above-grade obstructions. Suitable disposal sites for waste (including hazardous waste) must be identified, and local and DOT regulations and weight restrictions will have to be factored into transporting that waste.
One area many people fail to consider is protection for nearby power lines (and other utilities). The proximity of those power lines may mean that they’ll have to be terminated during the demolition, rerouted, or simply protected while work progresses. Otherwise, equipment may come in contact with them, or debris may cause damage.
The site will need proper warning signs and protective barriers to safeguard the community and people who may come into the area. The engineering survey should also spell out the needs for safety equipment and access to medical services, as well as a plan for responding to fires during the project. Finally, if there is a possibility that the demolition may require working in confined spaces, there should be a plan for confined space entry.
Finally, if the project is large enough, having a safety professional or other competent person on site throughout the process is a sound idea. That individual’s involvement and presence will allow for an immediate response to any new challenges that crop up during the demolition itself, minimizing any added risks and reducing delays to the project.