Glossary
The working vocabulary of abatement and demolition.
46 terms and counting. If a term you'd look up isn't here, email us and we'll add it.
A
ACBM
Any material in a building that contains more than 1% asbestos by weight, as defined by AHERA.
ACM
Any material containing more than 1% asbestos by weight. The umbrella term; AHERA's building-specific version is ACBM.
Action Level
The exposure threshold that triggers OSHA's requirements for medical surveillance, exposure monitoring, and training, set below the permissible exposure limit.
AHA
A written analysis of a specific task: the steps, the hazards each step creates, and the controls in place for each hazard.
AHERA
The 1986 federal law (40 CFR Part 763) governing asbestos in schools: inspections, management plans, and accredited inspectors and designers.
Amended Water
Water with a wetting agent (surfactant) added so it soaks into asbestos-containing material more effectively during wet removal.
Asbestos Inspector
An AHERA-accredited professional who inspects buildings for asbestos-containing material, collects samples, and assesses condition. The basis for management plans and pre-demolition surveys.
C
Class I Work
The most stringent category of asbestos work under OSHA 1926.1101: removal of thermal system insulation or surfacing material that contains asbestos.
Class II Work
Removal of asbestos-containing material other than thermal system insulation and surfacing material: typically wallboard, floor tile, roofing, siding, transite.
Class III Work
Repair and maintenance operations where ACM, including TSI and surfacing material, is likely to be disturbed.
Class IV Work
Custodial activity where employees clean up ACM-contaminated waste, debris, or dust.
Clearance Air Sample
Air samples taken at the end of an asbestos abatement project to verify that fiber concentrations in the work area meet the clearance criterion before the area is re-occupied.
Competent Person
A person who is capable of identifying existing and predictable hazards and who has authorization to take prompt corrective measures.
E
Encapsulation
Treating ACM with a sealant that either coats the surface (bridging encapsulant) or penetrates the material (penetrating encapsulant) to bind the asbestos fibers.
Enclosure
Constructing an airtight, impermeable, permanent barrier around ACM to prevent fiber release into the occupied space.
Engineering Survey
A pre-demolition written survey by a competent person of the structure, its framing, floors, and walls, to identify any potential collapse hazard.
Excursion Limit
A short-term (commonly 30-minute) exposure limit, set above the 8-hour TWA PEL, that cannot be exceeded at any time.
F
Fit Test
A test that verifies a particular respirator model and size achieves an acceptable seal on a specific worker's face.
Friable
Material that, when dry, can be crumbled, pulverized, or reduced to powder by hand pressure. Friable ACM is the most regulated category of asbestos-containing material.
H
N
Negative Exposure Assessment
A documented demonstration under OSHA 1926.1101 that exposure during a specific operation will stay below the PEL, relieving the employer of certain monitoring and control requirements.
Negative Pressure Enclosure
A temporary containment around an asbestos work area, maintained at lower air pressure than the surrounding space so that air flows in but not out, preventing fiber escape.
NESHAP
EPA's air-toxics rule. For asbestos work, NESHAP at 40 CFR 61 Subpart M governs notification, work practices, and waste disposal for renovations and demolitions.
Non-Friable
ACM that cannot be crumbled, pulverized, or reduced to powder by hand pressure when dry. Generally less likely to release fibers than friable ACM.
P
PACM
Material that, by virtue of its type and age, is presumed to contain asbestos unless tested and shown not to.
PCM
An optical microscopy method (NIOSH 7400) used to count airborne fibers. The standard method for asbestos exposure monitoring under OSHA.
PEL
OSHA's enforceable maximum employee exposure to an airborne contaminant, typically expressed as an 8-hour time-weighted average.
Phase I ESA
A review of a property's history and current conditions to identify potential environmental contamination, following ASTM E1527. The first step in environmental due diligence.
Project Designer
An AHERA-accredited professional who designs asbestos abatement projects — containment, work practices, and clearance criteria. Many states require one for larger jobs.
R
RACM
EPA NESHAP's term for friable ACM, plus non-friable ACM that has become friable, or that will be subjected to demolition forces likely to crumble it.
Regulated Area
A demarcated, access-restricted area where airborne asbestos may exceed the PEL. Required for Class I and II asbestos work under OSHA 1926.1101.
RRP Rule
EPA's lead-safe work practice rule (40 CFR Part 745 Subpart E) for renovation, repair, and painting in pre-1978 housing and child-occupied facilities.
T
TEM
An electron microscopy method that can confirm fiber composition and is required for AHERA clearance air sampling in schools.
TSI
Insulation on pipes, boilers, tanks, ducts, and similar components to control heat transfer or condensation. One of AHERA's three asbestos material categories, and a frequent location for friable asbestos.
TWA
Time-weighted average: airborne exposure averaged over a period, usually 8 hours. OSHA's asbestos PEL is 0.1 f/cc as an 8-hour TWA.
W
Waste Shipment Record
The NESHAP chain-of-custody document that tracks asbestos-containing waste from the generator through the transporter to the approved disposal site.
Wet Methods
Wetting asbestos-containing material before and during removal to suppress fiber release. A core work-practice control under both OSHA and NESHAP.
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