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Published: October, 2014; Vol 11, Num 5

 

Demolition Safety Requires Careful Planning

By Travis Parsons

Every day, Laborers across the United States and Canada perform a variety of tasks, including demolition work. Like any field in construction, demolition presents its own unique hazards that require careful planning and preparation. If these steps aren’t followed, tragedy can easily result.

On June 20, 2014, a construction worker in New Jersey was trapped and killed when the last standing wall of a building under demolition collapsed on top of him. Six months earlier, a construction worker in Chicago was struck and killed by pieces of falling concrete while conducting renovations on a shopping mall. These tragedies followed the 2013 collapse of a four-story building in Philadelphia that killed six people and injured 14 more.

 

Demolition has a reputation for being “construction in reverse, with additional hazards.” Many of the hazards associated with demolition can be avoided through appropriate planning, sequencing and coordination of tasks. This planning includes the methods used to bring down the structure, the equipment necessary, required personal protective equipment (PPE) and appropriate worker training. One of the most critical steps in demolition planning is carrying out an engineering survey of the structure. OSHA’s demolition standard requires this survey be conducted in writing by a competent person. This violation is at the top of OSHA’s list of citations for demolition sites.

OSHA’s Top 5 Demolition Site Violations

1. Lack of a written engineering survey

2. Inadequate fall protection

3. Improper shoring or bracing of walls

4. Insufficient inspections of stairways & ladders

5. Testing & removal of hazardous materials

Demolition sites pose physical as well as health hazards to workers. But with proper planning, these and other common hazards can be avoided or controlled.

Collapses

Changes to a structure’s original design, as well as the unknown strength or weakness of certain construction materials (e.g., post-tensioned concrete), can lead to the collapse of walls or floors during demolition. An engineering survey will determine areas where premature collapses may occur. These areas should then be shored or braced prior to demolition to ensure a safe work environment. Any areas that have been previously damaged via fire, flood or other causes should also be shored or braced. Beginning at the top of the structure and demolishing exterior walls and floors while proceeding downwards also reduces the chances of a collapse.

Falls

Falls are another major physical hazard often present on demolition sites. Wall openings should be protected by guardrails to a height of approximately 42 inches, and floor openings should be marked and covered with a material able to withstand the loads that will be imposed. Fall protection is often necessary (e.g., for workers in aerial lifts). In addition, stairs and ladders should be properly installed, inspected and have proper illumination.

Hazardous Materials

Demolition work is often performed on old structures that are more likely to include hazardous materials such as asbestos, lead or heavy metals requiring special material handling. If these materials are present (testing may be required for confirmation), their removal should be factored into the work scheduling and performed before demolition work begins. Other hazardous materials such as chemicals, gases, explosives or flammable materials should also be removed prior to the beginning of demolition work.

Noise

Demolition operations often cause noise levels that exceed the requirement for hearing protection. These levels are caused by the use of explosives, machinery or other tools, and should be controlled through the use of engineering controls (e.g., equipment modification and/or the use of barriers), administrative controls (e.g., worker isolation or rotation) and hearing protection. Sometimes, a combination of controls and hearing protection is needed for proper protection.

Dust

As many Laborers can attest, demolishing structures creates a large amount of dust. Breaking up concrete and other building materials such as drywall releases silica dust into the air, and exposures to other types of dust are also harmful to workers. These exposures can be drastically reduced through the use of engineering controls such as wet methods. When exposures can’t be reduced below safe levels through engineering or administrative controls, the appropriate respirator should be worn during dust-generating tasks.

Demolition sites bring unique challenges, but with careful planning, sequencing and worker training, most demolition hazards and incidents can be prevented. Creating a safe and healthful environment for workers, visitors and bystanders takes the collective effort of every person on a demolition site.

[Travis Parsons is the LHSFNA’s Senior Safety & Health Specialist.]