In this post we will discuss the demolition and salvage of unsafe and unsound buildings. We look at the proper precautions that demolition contractors must take when deconstructing unsafe buildings, and we also will examine what constitutes a structurally unsound building.
Defining and Surveying Structurally Unsound Buildings
A structurally unsound building is one that is in danger of collapse. Here in Portland, Oregon, demolition contractors and others can easily pick out unsafe buildings because the City of Portland posts a huge red “U” on unsafe buildings. Unsafe buildings pose various hazards that must be addressed during the demolition process. One thing to consider is the use of high-reach demolition excavators. High-reach excavators ensure the safety of workers by allowing them to demolish the upper levels of a “U” building where it’s unsafe to work and avoid the hazards of falling debris. Among some demolition contractors, there may be a tendency to address issues that are immediately life threatening, while overlooking less obvious dangers such as asbestos, PCBs, or lead, that still pose serious health risks to those exposed.
A dilapidation survey may be used to identify and record building defects through photographic and digital documentation. Although especially critical to the field of building conservation, a dilapidation survey is also useful before conducting demolition work, because it can help identify potential hazards such as fungus, mold, asbestos, and peeling paint (which may contain lead).
Asbestos Removal: A Case Study of Unsafe Building Material
To appreciate the complexity involved with removing hazardous materials from unsafe buildings, let’s consider just one toxic building material, asbestos. Dangerous concentrations of asbestos can exist if asbestos-containing materials are disturbed. Airborne asbestos can cause lung cancer and mesothelioma, a cancer of the lungs and abdominal linings. In the United States, the Environmental Protection Agency has issued a series of guidelines and regulations concerning the removal and treatment of asbestos. Proper removal of asbestos from a demolition jobsite involves 4 steps:
1. Identification. Materials that contain asbestos must first be identified. These may include asbestos-cement corrugated sheet, asbestos-cement flat sheet, asbestos pipeline wrap, roofing felt, vinyl-asbestos floor tile, asbestos-cement shingle, millboard, asbestos-cement pipe, and vermiculite-attic insulation.
2. Notification of Experts. Persons and firms conducting demolition work should contact the appropriate state/local air management program. At least one person who is trained in NESHAP (National Emission Standards for Hazardous Air Pollutants) regulations should be available in person or via phone during the demolition process.
3. Demolition. During demolition, safety equipment, including respirators, must be worn. It is important to wet the structure to help contain the spread of airborne asbestos particles. The EPA recommends knocking down each wall individually, folding it in on itself to minimize excess breakage of materials containing asbestos. Demolition contractors should keep the debris wet, and segregate asbestos- containing materials as much as possible.
4. Removal. Contain asbestos-containing material using leak proof wrapping. For large quantities, use heavy equipment to place the dampened, contaminated material into dump trucks, which have a plastic liner on the bottom of the bed to minimize the leakage of tainted water. Seal the debris with a tarp, and label it with a large placard with the following warning: “Warning: Asbestos Hazard. Stay Away.” Drive the truck to a certified asbestos disposal site.
As you can see, the proper ecological steps required for Asbestos removal are quite complicated. Now consider that this is just one unsafe material involved in demolition.
Other Hazardous Material
Lead, PCBs, solvents, pesticides, pool chemicals, cleaning compounds, radioactive materials, and other solutions also create potential hazards during the demolition process. Inexperienced demolition technicians should contact their state environmental agency for directives on how to dispose of these hazards.
The release of petroleum or other hazardous substances from underwater or above ground storage tanks pose particular hazards, especially in the wake of natural disasters such as hurricane Katrina. Gasoline pumps, pump station islands, and vent pipes all pose particular hazards. If discovered, demolition should halt, the area should be sealed off, and appropriate authorities called.
Any building that is in danger of collapse demands particular attention from demolition contractors. Structurally unsound buildings may contain dangerous materials, such as asbestos, each of which has its own required disposal steps according to environmental regulations. To avoid exposing yourself and your workers to deadly toxins, it’s best to leave the demolition of structurally unsound buildings to experienced contractors. Contact us today to learn about how we can safely decommission your unsafe building.
[photo by: Daniel Arauz on Flickr via CC License]