NC Asbestos Abatement flashcards
NC Asbestos Abatement · Build recall with a focused review session.
33 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Definition of ACM
- Asbestos-containing material is any material containing more than 1 percent asbestos by weight, determined by polarized light microscopy of a bulk sample.
- Six regulated asbestos minerals
- Chrysotile (serpentine group) plus five amphiboles: amosite, crocidolite, anthophyllite, tremolite, and actinolite. All are regulated as asbestos.
- Fiber counting criteria
- A countable fiber is longer than 5 micrometers, has an aspect ratio of at least 3:1, and is narrower than about 3 micrometers, per the phase contrast microscopy method.
- Friable material
- Material that can be crumbled, pulverized, or reduced to powder by hand pressure when dry. Friable ACM releases fibers easily and is subject to stricter work practice rules.
- Non-friable ACM
- Material that cannot be reduced to powder by hand pressure. It can become regulated when sanded, ground, cut, or abraded, releasing fibers.
- Mesothelioma latency
- Mesothelioma typically develops 20 to 50 years after asbestos exposure, and no safe exposure threshold has been established for this cancer.
- Asbestosis
- A dose-related, progressive lung fibrosis caused by accumulated asbestos fibers. Latency is usually 10 to 20 or more years after first significant exposure.
- Smoking synergy
- Cigarette smoking and asbestos exposure multiply lung cancer risk far beyond either alone, though smoking does not cause mesothelioma or asbestosis by itself.
- Amphibole persistence
- Amphibole fibers such as amosite and crocidolite remain in lung tissue much longer than chrysotile, which is more readily cleared and dissolves in acidic environments.
- Bulk sampling hierarchy
- Sample friable ACM first, then non-friable ACM likely to become friable, then remaining suspect material. Minimum sample counts depend on homogeneous area size.
- Homogeneous area
- A surface area of uniform color and texture, applied at the same time, that can be represented by a set of bulk samples.
- Polarized light microscopy
- PLM is the standard method for analyzing bulk samples. It identifies mineral type and estimates percentage using refractive index, color, and optical properties.
- Phase contrast microscopy
- PCM counts airborne fibers from personal air samples (NIOSH 7400). It counts all fibers meeting size criteria, not just asbestos, so results are an upper bound.
- Permissible exposure limit
- The OSHA PEL for asbestos is 0.1 fibers per cubic centimeter as an 8-hour time-weighted average, with an excursion limit of 1.0 f/cc over 30 minutes.
- Removal preference
- Removal is the preferred abatement method because it permanently eliminates the hazard. Enclosure and encapsulation leave material in place and require ongoing management.
- Enclosure
- Airtight barrier installed over ACM to isolate it from occupied space. It does not remove the material and must be inspected and maintained.
- Encapsulation
- Sealing the surface of ACM with a penetrating or bridging sealant to bind fibers. Penetrating sealants absorb into the material; bridging sealants form a surface coating.
- O&M program
- An operations and maintenance program manages ACM left in place through training, work practices, periodic inspection, and recordkeeping to prevent fiber release during routine building activity.
- Negative pressure enclosure
- A containment maintained at a pressure differential of at least 0.02 inches of water column below adjacent areas, using HEPA negative air machines.
- Air changes per hour
- The number of complete enclosure air volume exchanges per hour. NPEs are typically sized to provide at least 4 air changes per hour.
- HEPA filter
- A high-efficiency particulate air filter removes at least 99.97 percent of airborne particles 0.3 micrometers in diameter. HEPA vacuums and negative air machines use them.
- Wet methods
- Applying water or amended water to ACM before and during disturbance to suppress fiber release. Dry sweeping and compressed air are prohibited.
- Glove bag
- A sealed bag with built-in gloves that encloses small components such as pipe sections, allowing removal without a full containment.
- Decontamination unit
- A sequence of dirty room, shower, and clean room through which workers and equipment pass to prevent fibers leaving the work area.
- Waste packaging
- ACM waste is wetted and sealed in leak-tight containers, often doubled 6-mil bags or drums, labeled with the required asbestos warning before transport.
- Clearance sampling
- Air sampling conducted after visual inspection confirms no visible dust or debris. Final results must fall below the project's clearance criterion before reoccupancy.
- Aggressive sampling
- A clearance sampling technique that uses forced air movement, such as a leaf blower or fan, to dislodge settled fibers and confirm the space is truly clean.
- Respirator selection
- Half-mask air-purifying respirators with P100 filters are minimum for many tasks. Full-face PAPRs or supplied-air units are used for higher exposures.
- Medical surveillance
- Required for workers exposed above the PEL or excursion limit for 30 or more days per year. Includes medical history, physical exam, and chest imaging.
- Competent person
- A person capable of identifying asbestos hazards and authorized to take corrective action. Required on site for many construction and abatement activities.
- Project designer
- A trained professional who writes the abatement scope, selects control methods, specifies containment and clearance criteria, and prepares project specifications.
- Air monitoring
- Personal and area air samples collected during abatement to document exposure. Results at or above the PEL trigger respiratory protection and surveillance obligations.
- Worker hygiene
- No eating, drinking, or smoking in the work area. Wash hands and face before breaks, shower at end of shift, and keep contaminated clothing separate.