Here are some of the most frequently asked questions about asbestos, as well as, timely answers to them.
What is asbestos?
Asbestos is a group of naturally occurring fibrous magnesium-mineral silicates. These fibers are strong and flexible and are mined from the earth. Asbestos is unique because when it is crushed, it breaks down into smaller and smaller fibers.
The needle-like shape of an asbestos fiber allows it to bypass the body’s defenses in the respiratory system and to possibly cause medical problems for people exposed to airborne asbestos fibers. The primary health effects of asbestos result from inhaling asbestos fibers.
What are the properties of asbestos?
In general, asbestos is inexpensive, has great tensile strength, and has substantial resistance to heat, electricity, fire, and chemicals. These properties make asbestos desirable to use:
- as insulation
- in acoustical materials
- as fireproofing
- in anticorrosive products
Each variety of asbestos has unique properties.
What is an ACM (asbestos-containing material)?
Any material composed of more than 1 percent asbestos is considered an ACM (asbestos-containing material).
The EPA (Environmental Protection Agency) and OSHA (the Occupational Safety and Health Administration) consider materials that contain 1 percent or less asbestos to be non-asbestos-containing materials. These materials are not regulated under the EPA’s NESHAP.
What characteristics does ACM in good condition have?
To be classified in good condition, ACM:
- must be relatively free of damage
- cannot be scratched, nicked, or crushed
- cannot separate from the surface, show water damage, or have uncovered friable ends
What are friable and non-friable asbestos?
- Friable asbestos can be crushed, crumbled, or pulverized by hand pressure. Friable asbestos is considered the most hazardous, because disturbing friable asbestos more readily creates airborne fibers that can be inhaled or ingested.
- Non-friable asbestos cannot be crushed, crumbled, or pulverized by hand pressure. Non-friable material can be rendered friable by mechanical or other means, such as sanding, grinding, cutting, or abrading.
In the latest EPA NESHAP revision (40 CFR Part 61; November 20, 1990, and corrected January 16, 1991), two non-friable categories were created:
- Category I non-friable ACM: Includes asbestos-containing packings, gaskets, resilient floor covering, and asphalt roofing products that contain more than 1 percent asbestos.
- Category II non-friable ACM: Includes any material, excluding Category I non-friable ACM, containing more than 1 percent asbestos.</UL
What is RACM (regulated asbestos-containing material)?
The EPA NESHAP revision created the term RACM (regulated asbestos-containing material). RACM includes:
- friable asbestos material
- Category I non-friable ACM that has become friable
- Category I non-friable ACM that has been or will be sanded, ground, cut, or abraded
- Category II non-friable ACM that has a high probability of becoming or has already become crumbled, pulverized, or reduced to powder by the forces expected to act on the material during the demolition or renovation operations regulated by 40 CFR 61
What are the three ACBM (asbestos-containing building materials) categories?
The three AHERA ACBM categories, indicating where the ACBM is applied and how it was manufactured, are:
- TSI (thermal system insulation): often an insulating cement or mud used to inhibit heat transfer or prevent condensation on pipes, boilers, tanks, ducts, and various other components of hot- and cold-water systems and HVAC (heating, ventilating, and air-conditioning) systems
- Surfacing materials: ACM sprayed on or applied to surfaces such as walls, ceilings, and structural members with a trowel for acoustical, decorative, or fireproofing purposes
- Miscellaneous materials: mostly non-friable asbestos products and materials such as ceiling tiles, floor tiles, roofing felt, Transite ® pipes and panels, exterior siding, fabrics, and drywall systems
The EPA’s AHERA (40 CFR Part 763) requires officials to identify any ACBM present in school buildings and develop management plans to monitor the asbestos until total removal is feasible.
What is PACM (presumed asbestos-containing material)?
According to OSHA, PACMs are materials presumed to contain asbestos unless that presumption is proven wrong by representative sampling and laboratory analysis.
The following materials are PACMs:
- TSI (thermal system insulation) on pipes, boilers, tanks, and ductwork
- sprayed on surfacing materials (for example, decorative plaster on ceilings, acoustical material on decking, and fireproofing on structural members)
- asphalt roofing
- vinyl flooring material in buildings constructed prior to 1981
What are the four classes of asbestos work activities defined by OSHA?
- Class I activity: Removal of ACM, PACM, TSI, and surfacing materials (friable materials)
- Class II activity: Removal of ACM and PACM that are not TSI or a surfacing material. These materials are non-
- friable materials such as floor tiles and sheeting, ACM wallboard, roofing and siding shingles, asbestos cement board, and construction mastics.
- Class III activity: Repair and maintenance operations, or small-scale or short-term removal, whereby damaged asbestos-containing surfacing materials and/or TSI are likely to be disturbed, and the disturbed material fits into a 60-inch glove bag.
- Class IV activity: Maintenance, custodial, or janitorial activities during which employees touch but do not disturb ACM or PACM. These activities may involve cleaning dust, waste, and debris contaminated with asbestos dusts created by Class I, II, and III activities.
How are building occupants exposed to ACM?
When ACM is intact, the potential for exposure is minimal. When disturbed, however, ACM produces microscopic airborne fibers that can be inhaled. Building occupants are normally unaware of exposure dangers, since asbestos fibers are small and thin enough to be invisible to the naked eye. There are no immediate or acute symptoms such as rashes, sneezing, coughing, or eye irritation to warn someone of an exposure problem.
What are asbestos-related diseases?
Generally, asbestos-related diseases have an incubation period of 20 to 40 years. This means that after a person is exposed to asbestos, adverse health effects may not appear for 20 to 40 years. Three prominent asbestos-related diseases can be caused by inhalation of asbestos fibers:
- Asbestosis: A chronic, nonmalignant, progressive, irreversible lung disease that reduces lung capacity.
- Lung cancer: The uncontrolled growth of abnormal cells that occurs in the lungs.
- Mesothelioma: A rare cancer that affects the chest or abdominal cavity lining. (Asbestos exposure is the only known cause of this disease.)
How are asbestos fibers released?
Fibers can be released as a result of any of the following:
- Independent contractors: Contractors of all types (for example, plumbers, electricians, cleaning personnel, HVAC technicians) periodically perform work in buildings and could unknowingly damage ACM. Inform contractors of asbestos locations, require them to follow all regulations, and ask them to take precautions to avoid disturbing ACM.
- Water damage: A leaking roof or pipe, or any other water source, can cause damage to ACM. Most asbestos-containing products absorb water readily. When this happens, the wet material may separate from its applied surface or break up because of the additional weight.
- Air currents or plenums: A strong airflow against an asbestos-containing surface could cause surface erosion especially when the ACM is friable, such as in spray-applied fireproofing. An air plenum, air chamber, or mechanical room can have high air velocities that pull ACM from surfaces.
- Storage on or near ACM: Objects placed on or removed from the ACM can cause contact damage; whenever possible, avoid all contact with ACM when performing building activities.
- Uncontrolled asbestos abatement: This process should always be avoided. Independent contractors or even in-house staff can inadvertently cause uncontrolled asbestos abatement when the building lacks a good asbestos management program.
- Direct contact: Someone working with ladders, tools, or equipment in areas with hanging pipes can easily damage pipe insulation. A door constantly scraping against an asbestos ceiling or floor tile can cause abrasion.
- Maintenance: Building repairs can seriously disturb ACM unless the proper procedures are in place and the staff is trained.
- Renovation or demolition: Control the disturbance of asbestos during asbestos abatement or any other structural alteration.
- Vandalism: Vandals can unknowingly disturb ACM, especially in outdoor vessels, ducts, or piping.
- Tenant damage: It is difficult to control tenant activities, and the tenant’s employees may have no training or knowledge concerning asbestos issues.
What is the risk of exposure to ACM for building occupants?
Significant controversy exists about the risk of exposure to ACM for building occupants. Two conclusions are generally accepted, however:
- Those building employees most at risk are maintenance and trades personnel, especially if they are left unprotected and are poorly trained.
- Occupants of a building in which management has implemented a comprehensive asbestos control O&M (operations and maintenance) program have a lower risk.
How is an individual’s level of exposure measured?
An individual’s level of exposure is usually reported in f/cc (fibers per cubic centimeter) of air. To measure the number of fibers in the air, the air is allowed to flow through a filter, and the captured dust is analyzed under a microscope. The current OSHA PEL (permissible exposure limit) is 0.1 f/cc over an eight-hour day. In addition, the EL (excursion limit) of 1.0 f/cc is allowed over a sampling period of 30 minutes.
Remember that OSHA standards are in place to protect workers. The exposure levels specified in the asbestos standard are based on the PCM methodology and are meant to represent a typical eight-hour workday.
This article is excerpted from BOMI International’s Contaminants Reference Guide. The guide can be purchased by calling 1-800-235-2664, or by visiting www.bomi.org.
