44 terms defined
The asbestos dictionary
Every term you will meet on a laboratory report, in a contractor's scope of work, on a permit application or in an insurance adjuster's email — defined in one sentence, then explained properly.
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A
- Abatement
- Licensed removal or control of asbestos-containing material.
- Abatement is the regulated process of removing, encapsulating or enclosing asbestos-containing material using containment, negative air pressure, trained personnel and manifested disposal. It is performed by appropriately licensed contractors, not by general trades or homeowners.
- See also: Encapsulation · Enclosure · Containment
- ACM (Asbestos-Containing Material)
- Any material containing more than one percent asbestos.
- A building material is classified as asbestos-containing when laboratory analysis identifies greater than one percent asbestos. Materials at or below that threshold are not regulated as ACM, though they are not necessarily fiber-free.
- See also: PACM · One percent threshold
- Actinolite
- One of the six regulated asbestos minerals.
- An amphibole asbestos mineral, rarely used commercially in building products but included in the regulated list and occasionally found as a contaminant.
- Air monitoring
- Measuring airborne fiber concentration over a period of time.
- Air monitoring draws a measured volume of air through a filter and counts the fibers captured. It measures current exposure conditions and is used during abatement and for clearance, not to determine whether a material contains asbestos.
- See also: Clearance testing · Bulk sampling
- Amosite
- Brown amphibole asbestos, common in insulation and cement board.
- Amosite is an amphibole asbestos mineral widely used in thermal insulation, cement sheet and pipe products. Amphibole fibers are straight and needle-like and are generally considered more biologically persistent than chrysotile.
- Amphibole
- The straight-fiber family of asbestos minerals.
- Amphibole is the mineral group containing amosite, crocidolite, tremolite, anthophyllite and actinolite. Their straight, rigid fiber geometry allows deep lung penetration and migration to the pleura.
- See also: Serpentine · Chrysotile
- Anthophyllite
- A less common regulated amphibole asbestos.
- An amphibole asbestos mineral used only rarely in commercial products, sometimes appearing as a contaminant in talc and other mined minerals.
- Asbestosis
- Progressive lung scarring caused by inhaled asbestos fibers.
- Asbestosis is a chronic fibrotic lung disease resulting from prolonged inhalation of asbestos fibers. It causes shortness of breath and reduced lung capacity and typically appears ten to forty years after exposure.
- See also: Mesothelioma · Latency period
B
- Bulk sampling
- Taking a physical piece of material for laboratory analysis.
- Bulk sampling is the collection of a small representative piece of a building material so a laboratory can determine whether it contains asbestos. It is the standard method before renovation, demolition, sale or an insurance claim.
- See also: PLM · Homogeneous area
C
- Chain of custody
- The signed record tracking a sample from collection to laboratory.
- Chain of custody documentation records who collected each sample, when, and every transfer up to laboratory receipt. It is what makes a result defensible in an insurance claim, a permit file or a legal dispute.
- Chrysotile
- Curly serpentine asbestos; the most common type in US buildings.
- Chrysotile accounts for the large majority of asbestos used in American building products, including ceiling texture, floor tile, cement products and joint compound. Its fibers are curved and flexible.
- See also: Serpentine · Amphibole
- Clearance testing
- Air sampling that confirms an area is safe to reoccupy after abatement.
- Clearance testing is performed after abatement, usually with aggressive air movement, to confirm airborne fiber concentrations meet the criteria for reoccupancy. It is a distinct service from bulk material testing.
- See also: Air monitoring · Abatement
- Containment
- A sealed work area that prevents fiber escape during abatement.
- Containment uses plastic sheeting, sealed openings, negative air machines and decontamination units to keep released fibers inside the work area and out of occupied space.
- Crocidolite
- Blue amphibole asbestos, considered particularly hazardous.
- Crocidolite is an amphibole asbestos mineral with very fine, straight fibers. It is strongly associated with mesothelioma and was used in specialized insulation, cement and spray products.
- Cutback mastic
- Black asphaltic flooring adhesive that frequently contains asbestos.
- Cutback mastic is the tar-like adhesive used to install resilient flooring for decades. It is a separate material from the tile above it and often tests positive even when the tile does not.
- See also: Vinyl asbestos tile · Homogeneous area
D
- Demolition survey
- A full structure asbestos inventory required before demolition.
- A pre-demolition survey inventories and samples every suspect homogeneous material in a structure, producing a written report that must be available on site during demolition and that supports required air district notification.
- See also: Notification · Homogeneous area
- Dispersion staining
- An optical technique used with PLM to identify fiber type.
- Dispersion staining mounts a fiber in a liquid of known refractive index; the colours produced at the fiber edges identify the mineral, confirming asbestos type during PLM analysis.
- See also: PLM · Refractive index
E
- Encapsulation
- Sealing asbestos material in place with a bonding agent.
- Encapsulation applies a sealant that binds fibers together or coats the surface, preventing release without removing the material. It is a recognized and often less disruptive alternative to abatement.
- See also: Enclosure · Management in place
- Enclosure
- Building a permanent barrier over asbestos material.
- Enclosure covers asbestos-containing material with an airtight, impermeable barrier — for example, new drywall installed over a textured ceiling — leaving the original material intact behind it.
F
- Friable
- Material that crumbles under hand pressure and releases fibers easily.
- Friable asbestos-containing material can be reduced to powder by hand pressure when dry. Ceiling texture, pipe lagging and duct wrap are typical examples, and friable material is subject to stricter handling requirements.
- See also: Non-friable
G
- Glazing putty
- Window sealing compound that commonly contained asbestos.
- Glazing putty beds glass into a sash. Asbestos was added for flexibility and crack resistance, making it a frequent positive result during window replacement or restoration.
H
- Homogeneous area
- Material that is uniform in colour, texture and date of application.
- A homogeneous area is a single material installed at one time from one product. Sampling and results apply to the homogeneous area, which is why each distinct ceiling, floor layer or wall system needs its own sample.
L
- Latency period
- The decades-long delay between exposure and disease.
- Asbestos-related diseases typically appear ten to forty years after exposure. This latency is why exposure produces no immediate symptoms and why prevention rather than detection is the effective control.
M
- Management in place
- Keeping asbestos material intact and monitored rather than removing it.
- Management in place is a documented program of leaving undamaged asbestos material undisturbed, inspecting it periodically, repairing damage promptly and informing anyone who might disturb it. It is frequently safer and cheaper than removal.
- Mastic
- Adhesive compound used for flooring, roofing and flashing.
- Mastic is a general term for adhesive compounds used under flooring, on roofs and around flashing. Asbestos was a common additive, and mastics are sampled as separate materials from what they bond.
- Mesothelioma
- A cancer of the lung or abdominal lining strongly linked to asbestos.
- Mesothelioma is a malignancy of the mesothelial lining of the lungs, abdomen or heart. It is strongly specific to asbestos exposure and typically presents decades after the exposure occurred.
N
- NESHAP
- Federal air standards governing asbestos during renovation and demolition.
- The National Emission Standards for Hazardous Air Pollutants set federal requirements for asbestos surveys, notification, work practices and disposal during renovation and demolition. Local air districts implement and enforce them in California.
- See also: Notification · Demolition survey
- Non-friable
- Material where fibers are locked into a hard matrix.
- Non-friable asbestos material cannot be crumbled by hand pressure. Floor tile, cement siding, stucco and roofing are typical examples. It becomes hazardous when cut, ground, sanded or broken.
- See also: Friable
- Notification
- Advance notice to the air district before qualifying work.
- California air districts require advance written notification before demolition and before renovation work that exceeds specified thresholds of asbestos-containing material. Notification depends on a completed survey.
O
- One percent threshold
- The regulatory line defining asbestos-containing material.
- Material containing more than one percent asbestos is regulated as asbestos-containing. The threshold is a regulatory classification, not a statement that lower concentrations are biologically harmless.
- See also: Point counting · ACM (Asbestos-Containing Material)
P
- PACM (Presumed ACM)
- Material assumed to contain asbestos until tested.
- Presumed asbestos-containing material is thermal system insulation and surfacing material installed before 1981, plus in practice any suspect material in an older building, treated as positive unless laboratory analysis shows otherwise.
- Pleural plaques
- Thickened areas on the lung lining indicating past exposure.
- Pleural plaques are localized areas of fibrous thickening on the pleura. They are often symptomless but serve as a marker of previous asbestos exposure.
- PLM (Polarized Light Microscopy)
- The standard laboratory method for bulk building materials.
- Polarized Light Microscopy identifies asbestos in bulk samples by observing optical properties under polarized light, including birefringence, extinction angle and refractive index via dispersion staining. It is the EPA-recognized method for building materials.
- See also: TEM · Dispersion staining
- Point counting
- A statistical method for precisely quantifying asbestos percentage.
- Point counting overlays a grid on a prepared sample and records the mineral present at a defined number of points, typically four hundred. It produces a defensible percentage where a visual estimate sits near the one percent threshold.
R
- Refractive index
- An optical property used to identify mineral fibers.
- Refractive index describes how light bends passing through a material. Comparing a fiber's refractive index against known liquids is central to identifying asbestos type under PLM.
S
- Serpentine
- The mineral group containing chrysotile.
- Serpentine is the asbestos mineral group whose only commercial member is chrysotile, characterized by curly, flexible fibers rather than the straight needles of the amphibole group.
- Surfacing material
- Sprayed or troweled material applied to surfaces.
- Surfacing material includes spray-applied ceiling texture, acoustic coatings, fireproofing and decorative plaster. Pre-1981 surfacing material is presumed asbestos-containing until tested.
T
- TEM (Transmission Electron Microscopy)
- A high-resolution method used mainly for air clearance.
- Transmission Electron Microscopy resolves fibers far smaller than optical microscopy can detect. It is used for post-abatement air clearance and for materials with fibers too fine for reliable PLM analysis.
- Thermal system insulation
- Insulation on pipes, boilers, ducts and tanks.
- Thermal system insulation covers pipes, boilers, ducts, tanks and fittings to control heat loss. Pre-1981 thermal system insulation is presumed asbestos-containing and is frequently friable and damaged.
- Transite
- Cement-asbestos board used for siding, panels and flues.
- Transite is a trade name that became a general term for cement-asbestos board, used in siding, soffits, wall panels, flues and utility enclosures. It is hard, brittle and among the most reliably positive materials of its era.
V
- Vermiculite
- Loose-fill insulation that may be contaminated with asbestos.
- Vermiculite is a mineral used as loose-fill attic insulation. Material from certain historical sources carried tremolite contamination, so vermiculite attic fill should be treated as suspect and left undisturbed pending testing.
- Vinyl asbestos tile (VAT)
- Resilient floor tile manufactured with asbestos filler.
- Vinyl asbestos tile is resilient flooring made with asbestos as a filler and binder, most recognizable in the nine-by-nine inch format. It is non-friable when intact and becomes hazardous when cut, sanded or broken.
- See also: Cutback mastic · Non-friable
W
- Wet method
- Using water or amended water to suppress fiber release.
- Wet methods apply water, often with a surfactant, to material before and during disturbance to suppress airborne fiber release. Wetting reduces release but does not make untested removal of friable material acceptable.
- Work practice controls
- Procedures that limit fiber release during work.
- Work practice controls include wet methods, hand tools instead of power tools, mini-enclosures, HEPA filtration, controlled waste handling and decontamination. They are how regulated asbestos work is performed safely.
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The process
How asbestos testing works, step by step
01
Tell us what you are about to disturb
Call, text a photo, or send the form. We identify the suspect materials, the likely number of samples, and confirm the flat price before anyone is dispatched.
02
Certified inspector arrives and samples safely
Each homogeneous material is wetted, cut in a coin-sized piece, sealed, labeled and logged under chain of custody. The patch is smaller than a light-switch plate and the area is left clean.
03
Accredited lab analyzes by PLM
Samples are analyzed by Polarized Light Microscopy with dispersion staining — the EPA method for bulk building materials — with point counting available for borderline matrices.
04
Written report in 24 hours
You receive a PDF listing every sample location, the asbestos type detected and the percentage, ready to hand to a contractor, abatement firm or permit desk.
Asbestos knowledge base
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