Construction sites pose many hazards, and as OSHA puts it, demolition is “construction in reverse, with additional hazards.” Therefore, OSHA has dedicated extra time and attention recently to demolition safety, and it developed a resource page explaining the standards specifically related to this kind of work (29 CFR Part 1926, Subpart T). This emphasis on demolition safety came in the wake of a series of fatal accidents including the collapse of a four-story building undergoing demolition in Philadelphia that killed six workers in 2013.
Many of the hazards at demolition sites also exist in construction, but because old buildings are often involved in demolition, additional—often unseen—hazards are frequently present, too. Buildings may have been modified over the years, construction materials may have weakened and contaminants like lead and asbestos could be hidden within the structure’s materials, OSHA explains. Knowing what hazards to look for is a good first step to assessing a demolition project.
Common Hazards in Demolition
Like most construction sites, demolition sites contain hazards like falling objects, gases from using machinery, possible fires and working at heights, and these hazards need to be assessed.
In addition, those in charge of a demolition need to be aware of hazards related to contaminants like lead, asbestos, silica, mercury and PCBs. Hazards created by the demolition itself can also pose serious threats, as walls and other structures can collapse if they aren’t reinforced properly.
To make the worksite as safe as possible, certain steps need to be taken before work can begin. First, an engineering survey must be done to better understand the condition of walls, floors and the building’s frame. Next, a clear plan needs to be made for the demolition project that considers hazards, the steps of the project and plans for removing debris.
The following must be kept in mind when creating a demolition plan (although this list is not exhaustive):
- Deconstruction must occur from the top down. Materials cannot be removed from a story until work on the story above it has been completed.
- Ornamental portions of walls and ceilings should be removed before these structures are taken down.
- Some work areas—such as areas where machines or hot work are located—may need additional ventilation.
- Openings in the floor—for removing debris or other purposes—should not make up more than 25 percent of the floor’s area.
- Debris chutes should be enclosed.
- Railings may need to be built near ledges and openings.
- Walls and other structures may need to be reinforced while workers perform deconstruction in certain areas.
- Selective demolition, the process of tearing down part of a building, has unique hazards, but is still dangerous.
- In many cases, PPE will be necessary.
Before work can begin, all utility services like electricity, gas and water must either be shut off or capped outside the building. If these services are needed during demolition, they should be relocated and protected, according to The Associated General Contractors of America. The utility companies should always be notified about demolitions ahead of time as well.
Keep Workers Safe at Demolition Sites
As the Iowa Department of Transportation puts it in a video about demolition, “There’s a logic in destroying a structure, just like there is in building it.” For workers to be safe during construction, they need to understand the demolition plan so they can avoid being in the wrong place at the wrong time.
This means workers should be briefed about what will be going on at the site each day. It also means they should receive training about the hazards they face and any PPE they need to wear. This protective gear could include steel-toed boots with puncture-resistant soles, hardhats, gloves, fall protection, eye protection, hearing protection and respiratory protection. The variety of each type of PPE needed will depend on the specific hazards present. (For example, a different kind of respirator will be required when asbestos is present than when only dust is present.) Do an assessment of hazards to determine what types of PPE the worksite will require.
Demolition requires careful planning, but it can still involve sudden changes in the work environment because of the instability of the materials being dealt with. Everyone working at a demolition site should follow procedures and stay alert to prevent accidents.