What is Asbestos?
Asbestos is a naturally occurring mineral fiber. It was used in numerous building materials and vehicle products for its strength and ability to resist heat and corrosion before its dangerous health effects were discovered.
What is the hazard?
Asbestos fibers are released into the air during activities that disturb asbestos-containing materials. If the fibers are inhaled they can become trapped in the lungs or digestive system.
Where is the hazard?
Some materials are presumed to contain asbestos if installed before 1981. Examples of these materials, as well as other presumed asbestos-containing materials are:
- Thermal system insulation
- Roofing and siding shingles
- Vinyl floor tiles
- Plaster, cement, putties and caulk
- Ceiling tiles and spray-on coatings
- Industrial pipe wrapping
- Heat-resistant textiles
- Automobile brake linings and clutch pads
As long as asbestos building materials remain in good condition, the EPA insists they pose minimal health risks.
Why remove asbestos-containing building materials?
Sometimes, for construction projects, it is necessary to disturb asbestos-containing building materials and it is often the best time to just remove it all together. This is called asbestos abatement. Abatement can only be performed by properly trained and accredited asbestos professionals.
How will the asbestos be removed safely?
The U.S. Environmental Protection Agency and the NY Department of Labor have stringent regulations about asbestos removal, which is done only under rigorously controlled environmental conditions. The method to be used to control the removal environment is called a negative-pressure air filtration system. Negative-pressure filtration is a system that controls the flow and volume of air contained inside a removal work-site’s barrier walls. The primary purpose of the system is to prevent airborne asbestos from escaping outward past the barriers to contaminate the rest of the building’s air space. This is generally how the process works:
- The work site is completely sealed off with polyethylene sheeting. All openings that would allow the passage of air are sealed. The result is an airtight cocoon that completely envelops the workspace.
- A three-celled decontamination chamber is built to allow workers to pass into and out of the sealed work site. This decontamination unit has four successive sets of flapped door coverings.
They will allow outside air to pass inward, but fall shut to prevent inside air from escaping outward.
- Negative-pressure air filtration machines are installed in the enclosed work site. The air is drawn through the front of the unit and, after filtering out any asbestos fibers, it exhausts through the rear via ductwork or plastic, to the outdoors. The air passes through three stages of filters, including a 12-inch thick, high efficiency particulate air (HEPA) filter that traps microscopic particulate matter, such as the invisible asbestos fibers.
- When the machines are turned on, they pull in thousands of cubic feet of air each minute, filter any contaminants out of the air, and then forcibly exhaust that filtered air out of the sealed space to the outdoors. This rapid evacuation of air causes the air pressure within the sealed space to drop somewhat.
- The higher ambient air pressure outside the sealed barriers will then cause air to rush in toward the lower, or “negative,” pressure wherever it finds an opening.
- Once the machines are turned on, large volumes of air begin to move inward through the flapped doors of the three-chambered airlock. Enough filtration machines are installed so that together they can completely change all the air within the space every 15 minutes.
Negative-pressure filtration is the primary system that prevents the spread of asbestos contamination throughout the rest of a building’s air space. It also helps to protect the asbestos removal workers by constantly cleaning the air inside the site, thereby greatly lowering the workers’ overall potential for exposure. Negative air machines will run constantly throughout the project, until the work is complete and final air monitoring has been conducted by a third-party project monitor to show that air quality meets EPA’s final clearance air standards. At this point, the negative air machines are shut down and the containment structure is removed.
For your safety, and per state and federal regulations, warning signs will be posted at various locations outside the regulated area of the asbestos project, to prevent access to the work site. These signs are used to instruct on the asbestos hazards and the necessary personal protective equipment for entry into the work area. They will remain in place until final clearance air monitoring has been conducted.