Asbestos is a term for a group of naturally occurring minerals. These minerals are unique in that their molecular structure is fibrous in nature. This particular quality made asbestos minerals attractive to add to literally hundreds of building materials (pipe insulation, shingles, floor tile, mastics, roofing, acoustical treatments etc.). Asbestos was also used as a component of structural steel fire-proofing.
Hazards of Asbestos
Asbestos is a respiratory hazard and respiratory/gastro intestinal carcinogen. Exposure to asbestos occurs when respirable fibers are released into the air and then inhaled. Since exposure occurs when asbestos is inhaled, the best way to prevent exposure is to prevent asbestos fibers from becoming airborne.
Asbestos containing materials are therefore divided into two categories: friable and non-friable. Friable means that a material is able to be reduced to a powder by hand pressure. Asbestos containing materials that are friable, by their nature, have a much greater tendency to release fibers into the air and require extensive control measures to prevent releasing fibers into the air. Conversely, non-friable asbestos containing materials, by their nature, do not want to give up their fibers into the air. This class of materials must be mechanically impacted (power tools such as sanders, drills, chippers, saws, etc.) to release fibers.
There are several levels of protection to help prevent asbestos fiber release during fire-proofing removal projects.
The first level of protection takes place even before any fire-proofing material is touched. Negative air containments are constructed in the rooms/areas where removal will occur. These containments are maintained at a negative pressure to the rest of the building. This means that air always flows into the containment, not out, so anything floating around in the air inside the containment stays in the containment. Negative air machines pull air from inside the containment, filter it through HEPA Filters, and exhaust it outside the building. HEPA filters trap 99.97% of all particles greater than 3 microns in length.
The second level of protection is a regulatory requirement. Whenever asbestos containing materials are disturbed in any manner, the material must be wet. The contractor is required to thoroughly soak, with amended water, the fire-proofing material before it can be disturbed. Materials that are wet do not release respirable particles into the air.
The third level of protection is in the methods of removal. The contractor is required (by University's specifications and OSHA and EPA regulations) to use non-abrasive removal techniques. In simple terms, they can only use hand tools (scrapers, "scrubby" pads, etc.) to clean the fire-proofing material from the equipment and concrete. Hand removal methods do not impact the material with great amounts of energy, and therefore are much less likely to render the material airborne.
The fourth level of protection is how the materials are handled during and after removal. As soon as the fire-proofing is removed, it must be gathered up, double bagged in 6 mil thick plastic bags, and then sealed with duct tape. The materials also must be segregated into a dumpster used only for asbestos waste. No removed asbestos containing materials are permitted to accumulate in the containment.
The fifth level of protection is the workers themselves. In accordance with Pima County, Arizona and Federal regulations, the workers removing the fire proofing materials are trained and certified in accordance with an EPA recognized training program. The contractor is certified and registered for this type of asbestos work as well.
Some Other Information
It is a little disconcerting to see persons with respirators and white suits working in parts of the building. OSHA regulations require that all persons working with asbestos containing materials wear respiratory and other personal protection equipment while they are working, regardless of other control methods in place the prevent the release of fibers. The signs around the work areas and dumpsters are also an OSHA requirement so that everyone is aware that asbestos containing materials are being removed.