Asbestos Terminology Glossary

Comprehensive glossary of asbestos-related terms including health conditions, testing methods, and safety procedures

A

Asbestos

A group of naturally occurring fibrous minerals composed of thin, needle-like fibers. Asbestos was widely used in construction and manufacturing due to its heat resistance, strength, and insulating properties. When disturbed, asbestos releases microscopic fibers that can be inhaled, causing serious health problems including lung cancer, mesothelioma, and asbestosis. All types of asbestos are now recognized as carcinogenic.

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Asbestos Testing & InspectionAsbestos RemovalAsbestos Surveys

ACM (Asbestos-Containing Material)

Any material or product that contains more than 1% asbestos by weight. ACMs were commonly used in over 3,000 different products including insulation, fireproofing, roofing, flooring, and cement products. The identification and management of ACMs is crucial for protecting building occupants and workers from asbestos exposure.

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Asbestos Testing & InspectionAsbestos Bulk Sampling

Asbestos Fibers

Microscopic, thin, elongated particles that make up asbestos minerals. These fibers are typically less than 3 micrometers in diameter and can remain airborne for extended periods. When inhaled, they can penetrate deep into the lungs and remain there for years, potentially causing asbestos-related diseases. Fiber counting and identification is essential for exposure assessment and clearance testing.

Related services:

Asbestos Air MonitoringAsbestos Fiber Counting (PCM)

Amphibole Asbestos

A group of asbestos minerals with straight, needle-like fibers that are considered more harmful than chrysotile. Includes crocidolite (blue asbestos), amosite (brown asbestos), anthophyllite, tremolite, and actinolite. Amphibole fibers are more durable in lung tissue and are associated with higher rates of mesothelioma. These types are less common but more dangerous when exposure occurs.

Related services:

Asbestos Testing & InspectionMaterial Composition Analysis (PLM)

Amosite (Brown Asbestos)

An amphibole asbestos with straight, brown-gray fibers, considered the second most dangerous type after crocidolite. Amosite was commonly used in cement sheets, pipe insulation, thermal insulation products, and ceiling tiles. Its needle-like fibers are highly durable in lung tissue and strongly associated with mesothelioma and lung cancer.

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Asbestos Testing & InspectionAsbestos Removal

Asbestosis

A chronic lung disease caused by prolonged inhalation of asbestos fibers, resulting in scarring (fibrosis) of lung tissue. Symptoms include shortness of breath, persistent dry cough, chest tightness, and reduced lung capacity. Asbestosis typically develops after heavy occupational exposure over many years. While there is no cure, progression can be slowed by avoiding further exposure and managing symptoms.

Related services:

Asbestos Exposure ConsultationMedical Surveillance & Screening

See also:

AsbestosMesotheliomaAsbestos Fibers

Asbestos Survey

A systematic inspection of a building or structure to locate, identify, and assess the condition of asbestos-containing materials. Surveys are required before renovation or demolition work and for managing asbestos in occupied buildings. There are three main types: Management Surveys (for occupied buildings), Refurbishment Surveys (before renovation), and Demolition Surveys (before demolition). Surveys must be conducted by qualified and accredited professionals.

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Asbestos SurveysAsbestos Testing & Inspection

Asbestos Abatement

Procedures to control the release of asbestos fibers from asbestos-containing materials, including removal, encapsulation, enclosure, or repair. Abatement must be performed by licensed contractors following strict safety protocols including containment, negative air pressure, worker protection, and proper disposal. The goal is to eliminate or minimize asbestos exposure risk to building occupants and workers.

Related services:

Asbestos AbatementAsbestos RemovalAsbestos Encapsulation

See also:

AsbestosContainmentdecontamination

Asbestos Register

A documented record of all known and presumed asbestos-containing materials in a building, including location, type, condition, and assessment results. The register must be maintained and updated as materials are removed or conditions change. It serves as a key tool for managing asbestos risks and must be made available to anyone who might disturb the materials.

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Asbestos Management PlansAsbestos Surveys

Asbestos Management Plan

A comprehensive document outlining how asbestos-containing materials in a building will be managed to prevent exposure. Includes the asbestos register, risk assessments, control measures, monitoring schedules, emergency procedures, and training requirements. The plan must be reviewed regularly and updated when changes occur. Building owners and managers are legally responsible for maintaining an effective management plan.

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Asbestos Management PlansAsbestos Project Management

See also:

Asbestos RegisterRisk Assessment

C

Chrysotile (White Asbestos)

The most commonly used type of asbestos, accounting for approximately 95% of asbestos found in buildings. Chrysotile is a serpentine mineral with curly fibers, also known as white asbestos. While historically considered less dangerous than amphibole asbestos, it is now recognized as carcinogenic and capable of causing mesothelioma and other asbestos-related diseases.

Related services:

Asbestos Testing & InspectionMaterial Composition Analysis (PLM)

Crocidolite (Blue Asbestos)

The most dangerous type of asbestos, characterized by straight, blue needle-like fibers. Crocidolite is an amphibole asbestos that is extremely resistant to chemical and biological breakdown. It was primarily used in spray-on coatings, pipe insulation, and cement products. Even brief exposure to crocidolite can result in mesothelioma decades later.

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Asbestos Testing & InspectionAsbestos Removal

Containment

An enclosed work area constructed with polyethylene sheeting and sealed to prevent the escape of asbestos fibers during removal work. Containment includes critical barriers, airlocks, decontamination units, and negative air pressure systems. The integrity of containment must be maintained throughout the project and verified through air monitoring and visual inspections.

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Asbestos RemovalAsbestos Abatement

Clearance Testing

A series of inspections and air monitoring procedures conducted after asbestos removal to verify that the work area is safe for reoccupancy. Includes visual inspection, aggressive air sampling, and final air clearance testing. The area must meet strict criteria including visual cleanliness and airborne fiber concentrations below regulatory limits before containment can be removed.

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Asbestos Clearance / 4-Stage ClearanceAsbestos Air Monitoring

D

Demolition Survey (Type 3)

The most comprehensive type of asbestos survey, required before any demolition work. This fully intrusive survey aims to locate and describe all asbestos-containing materials in the building. The survey involves destructive inspection and is carried out in unoccupied buildings to ensure complete identification of ACMs. All asbestos must be removed before demolition can proceed.

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Asbestos SurveysAsbestos Testing & Inspection

Decontamination Unit

A series of connected chambers that workers pass through when entering or exiting an asbestos work area. Typically consists of a dirty room (for removing contaminated protective equipment), shower room (for washing), and clean room (for donning clean clothes). Proper use of decontamination units is essential to prevent fiber migration and worker contamination.

Related services:

Decontamination Units & EnclosuresAsbestos Removal

See also:

Containmentclean-roomshower-room

E

Encapsulation

A method of asbestos abatement that involves treating asbestos-containing materials with a sealant to prevent fiber release. Encapsulants penetrate the material or create a protective coating that binds the fibers together. This method is less expensive and disruptive than removal but requires ongoing monitoring and maintenance. Suitable only for materials in good condition that will not be disturbed.

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Asbestos EncapsulationAsbestos Abatement

Exposure Limit

The maximum permissible concentration of airborne asbestos fibers to which workers can be exposed over a specified time period. Regulatory limits vary by jurisdiction but typically include an 8-hour time-weighted average (TWA) and a short-term exposure limit (STEL). Employers must monitor exposure levels and implement controls to ensure compliance with these limits to protect worker health.

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Asbestos Air MonitoringAsbestos Exposure Consultation

See also:

permissible-exposure-limitcontrol-limit

F

Friable Asbestos

Asbestos-containing material that can be crumbled, pulverized, or reduced to powder by hand pressure when dry. Friable asbestos is considered more dangerous than non-friable asbestos because it can easily release fibers into the air. Examples include pipe insulation, spray-on coatings, and thermal insulation. Requires specialized handling and removal procedures with strict containment protocols.

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Friable Asbestos RemovalAsbestos Testing & Inspection

Four-Stage Clearance

A comprehensive clearance process consisting of: 1) Visual inspection of the work area, 2) Thorough cleaning and removal of waste, 3) Another visual inspection after cleaning, and 4) Air monitoring to verify fiber levels are below acceptable limits. All four stages must be successfully completed before the work area is certified as safe for normal occupancy.

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Asbestos Clearance / 4-Stage Clearance

H

HEPA Filter

High-Efficiency Particulate Air filter capable of capturing 99.97% of particles 0.3 micrometers or larger, including asbestos fibers. HEPA filtration is essential for negative air units, vacuum cleaners, and air monitoring equipment used in asbestos work. Regular testing and replacement of HEPA filters is critical to maintain containment and worker protection during asbestos removal operations.

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Asbestos Removal EquipmentAsbestos Air Monitoring

M

Mesothelioma

A rare and aggressive cancer affecting the mesothelium (protective lining of lungs, abdomen, or heart), primarily caused by asbestos exposure. The disease typically develops 20-50 years after exposure, making early detection difficult. Pleural mesothelioma (affecting the lung lining) is the most common form. There is no cure, and prognosis is generally poor, though treatments can extend survival and improve quality of life.

Related services:

Asbestos Exposure ConsultationMesothelioma Legal Assistance

See also:

AsbestosAsbestosisAsbestos Fibers

Management Survey (Type 1)

An asbestos survey designed to locate and assess asbestos-containing materials that could be damaged or disturbed during normal occupancy and maintenance of a building. This survey aims to ensure that nobody is harmed by the continuing presence of asbestos in the building. It involves sampling and analysis of suspected materials and creates an asbestos register and management plan.

Related services:

Asbestos SurveysAsbestos Management Plans

See also:

Asbestos SurveyAsbestos Register

N

Non-Friable Asbestos

Asbestos-containing material that is bonded or encapsulated in a cement, resin, or other binding material, making it difficult to crumble by hand when dry. Examples include asbestos cement sheets, floor tiles, and roofing materials. While considered less hazardous than friable asbestos when undisturbed, it can become friable through weathering, water damage, or mechanical damage.

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Asbestos Testing & InspectionAsbestos Removal

Negative Air Unit (NAU)

A ventilation system equipped with HEPA filters that creates negative air pressure within an asbestos work area, preventing contaminated air from escaping the containment. The unit continuously draws air from the work area, filters it through HEPA filters, and exhausts clean air outside. Proper placement and operation of NAUs is critical for worker and public safety during asbestos removal.

Related services:

Asbestos Removal EquipmentDecontamination Units & Enclosures

See also:

HEPA FilterContainmentair-pressure

P

PCM (Phase Contrast Microscopy)

A method of analyzing air samples to count asbestos fibers using a phase contrast microscope. PCM is the standard method for measuring airborne asbestos concentrations and verifying compliance with exposure limits. However, PCM cannot identify fiber type and counts all fibers meeting size criteria, potentially overestimating asbestos fiber concentrations.

Related services:

Asbestos Fiber Counting (PCM)Asbestos Air Monitoring

PLM (Polarized Light Microscopy)

A technique for identifying asbestos in bulk material samples using polarized light and optical properties. PLM is the standard method for analyzing building materials suspected of containing asbestos. The method can identify asbestos type and estimate concentration. Samples are typically collected during surveys and analyzed in accredited laboratories.

Related services:

Material Composition Analysis (PLM)Asbestos Bulk Sampling

R

Refurbishment Survey (Type 2)

A fully intrusive asbestos survey required before any refurbishment or renovation work. This survey is used to locate and describe all asbestos-containing materials in the area where the work will take place. The survey is intrusive and involves destructive inspection to access areas not visible in a management survey. All ACMs must be removed before refurbishment work begins.

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Asbestos SurveysAsbestos Testing & Inspection

Risk Assessment

A systematic evaluation of the potential for asbestos exposure based on material type, condition, location, accessibility, and likelihood of disturbance. Risk assessments assign priority ratings to ACMs to determine appropriate management actions. High-risk materials may require immediate removal, while low-risk materials may be managed in place with regular monitoring and maintenance.

Related services:

Asbestos Risk AssessmentAsbestos Consulting

T

TEM (Transmission Electron Microscopy)

The most sensitive and accurate method for analyzing asbestos in air and bulk samples. TEM can identify fiber type, measure very small fibers, and provide definitive asbestos identification. This method is required for final clearance testing after asbestos removal and can detect fibers as small as 0.001 micrometers. TEM is more expensive and time-consuming than PCM but provides superior accuracy.

Related services:

Asbestos Fiber Counting (TEM)Asbestos Air Monitoring

W

Wet Removal Method

A technique for removing asbestos-containing materials using water or wetting agents to minimize fiber release. Materials are thoroughly wetted before, during, and after removal to keep fibers from becoming airborne. This is the preferred method for most asbestos removal work. However, wet removal is not suitable for all materials or situations, such as when water damage to underlying materials must be avoided.

Related services:

Asbestos RemovalAsbestos Abatement

See also:

wetting-agentdust-suppression

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