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Asbestos. Dr Jim Lister Environment Group Manager. Asbestos. Asbestos is the generic name for six naturally occurring minerals Physical properties Strength Flexibility Insulating Properties Resistance to heat and Chemicals Low electrical conductivity. Types of asbestos.
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Asbestos Dr Jim ListerEnvironment Group Manager Glasgow Scientific Services
Asbestos • Asbestos is the generic name for six naturally occurring minerals • Physical properties Strength Flexibility Insulating Properties Resistance to heat and Chemicals Low electrical conductivity Glasgow Scientific Services
Types of asbestos • Chrysotile (white) White curly fibres • Amosite (brown) Straight sharp fibres • Crocidolite (blue) Straight fibres • Other Types Anthophyllite, Tremolite and Actinolite Glasgow Scientific Services
Asbestos - The Hazard • Asbestos is the single biggest cause of work related deaths in the UK. - HSE • 3000 Deaths per year associated with Asbestos - due to past exposure • Airborne Hazard – Fibres are produced when asbestos containing materials are disturbed • Respirable fibres – enter lung – cause fatal disease • Materials that remain undisturbed – no risk to health Glasgow Scientific Services
Risk Factors • Asbestos related diseases are caused by the inhalation of Asbestos fibres. • Fibres have to be respirable. Specific dimensions • Risk Factors CONCENTRATION + DURATION = DOSE • Some evidence that Asbestos diseases follow a dose response relationship. Glasgow Scientific Services
Latency Period For Asbestos Disease • Time taken from first exposure to discovery of illness. • Shortest latency period is 5-10 years • It can often take up to 40 years or more • No safe level of exposure • Secondary Exposure Glasgow Scientific Services
Asbestos diseases • Fibres that are not cleared from the lungs and remain trapped in the body can cause a range of diseases. • Asbestos lung cancer- fibres remaining trapped in the lung –severe respiratory damage High Asbestos concentrations • Mesothelioma- translocation of fibres to the pleura causing malignant disease in the thin membranes lining the chest. - Lower Asbestos concentrations Glasgow Scientific Services
Identification of Asbestos - Principle • Survey area-collect representative samples of all suspect materials. • Visual Examination of Bulk Material • Removal of sub-samples ( usually fibrous material ) from the bulk material • Mounting sub-sample on slide and clearing with acid or solvent. • Microscopal examination using plane and polarised light. Glasgow Scientific Services
Identification of Asbestos - Equipment • Glass Jars or polythene bags for collection of samples • Disposable gloves • Tweezers/pliers • Wash bottle (water) • Microscope slides and cover slips • Tissues • Hydrochloric acid, solvent • Polarising microscope Glasgow Scientific Services
Identification of Asbestos • Assess and survey the area and secure a representative sample. • Place sample jar/ bag in fume cupboard • Sort through sample with tweezers – transfer any fibrous material to slide (ensure representative sample is taken, sample all fibres) • Clear filler material Glasgow Scientific Services
Identification of Asbestos • Examine the slide microscopically – scanning the entire slide – using plane light and polarising any suspicious fibres. • Clean-up • Return Slides to glass Jar/ bag. • Clean the fume cupboard surfaces – vacuum cleaner fitted with suitable filter, wet wipes. • Place all material in labelled “asbestos” bag for special disposal. Glasgow Scientific Services
Example of ACM Board material Glasgow Scientific Services
Example of ACM - Insulation Glasgow Scientific Services
Example of ACM - Painted board Glasgow Scientific Services
Example of ACM - Asbestos rope Glasgow Scientific Services
Example of ACM - Floor tiles Glasgow Scientific Services
Example of ACM - Toilet Cistern Glasgow Scientific Services
Example of ACM - Corrugated Roofing Glasgow Scientific Services
Example of ACM - Sprayed Insulation Glasgow Scientific Services
Chrysotile Asbestos Teased out fibres Fine Wispy Fibres Knee bend Glasgow Scientific Services
Chrysotile Asbestos Fibres glow bright white on polarisation. Glasgow Scientific Services
Amosite Asbestos Bundles of sharp tightly packed fibres Straight rigid fibres Glasgow Scientific Services
Amosite Asbestos Polychromatic “rainbow” effect on polarisation Glasgow Scientific Services
Crocidolite Asbestos Fibres not as rigid as Amosite Fibres Dark inky Blue Wispy fibres present where the fibre bundles are teased out Glasgow Scientific Services
Crocidolite Asbestos Fibre bundles exhibit a red/brown appearance on polarisation Glasgow Scientific Services
Cotton Fibres Ragged fibre ends Distinct Cellular structure Fibres twisted and bent Often - Polychromatic effect without polarisation Glasgow Scientific Services
Cotton fibres Polychromatic effect within cellular structure not along fibre Glasgow Scientific Services
Hemp Ragged fibre ends Cellular structure Polychromatic effect present with or without polarisation Glasgow Scientific Services
Hemp Ragged fibre ends Polychromatic effect present with or without polarisation Glasgow Scientific Services
Jute Distinct cellular structure, ragged fibre ends, polychromatic effect. Glasgow Scientific Services
Glass fibre Transparent Fibre Ends truncated Variable diameter No effect on polarisation Glasgow Scientific Services
Polymeric fibre (polyester) Fibre ends blunt Single filament Regular diameter Bending or curvature Glasgow Scientific Services
Polymeric fibre (polyester) Polychromatic effect Glasgow Scientific Services