Term
| Five properties of asbestos that made it commercial in building trades |
|
Definition
Flexibility, high tensile strength,
incombustibility, low thermal conductivity, and resistance to chemical attack |
|
|
Term
CAR defines asbestos as any of
the following fibrous silicate minerals? |
|
Definition
Chrysotile crocidolite, amosite, asbestos anthophyllite,
asbestos actinolite or asbestos tremolite |
|
|
Term
| Silicate minerals are classified by? |
|
Definition
the number and arrangement of silicate tetrahedra in the
repeating units of the crystal lattice |
|
|
Term
Chrysotile is classified as a sheet silicate and is a member
of which group? |
|
Definition
|
|
Term
| Types of asbestos in the amphibole Group |
|
Definition
crocidolite, amosite, anthophyllite,
actinolite or tremolite |
|
|
Term
low percentages of asbestos can be
present in other mined products such as? |
|
Definition
|
|
Term
| Type of microscope used for the initial examination of the sample |
|
Definition
| low-power stereo-microscope |
|
|
Term
| Fibres observed in the course of stereo microscope examinations are categorised tentatively on... |
|
Definition
the basis of morphology and
certain physical properties |
|
|
Term
| Fibres suspected of being Asbestos are.. |
|
Definition
mounted in a refractive index (RI) liquid chosen to match the most likely
asbestos type |
|
|
Term
| The second microscope used to identify the asbestos type? |
|
Definition
| polarised light microscopy (PLM) |
|
|
Term
| PLM microscope magnification |
|
Definition
| from about 80x upwards, as appropriate to the type of sample |
|
|
Term
Finish the sentence...
If samples are
non-homogeneous and consist of layers of different material or are samples of debris
made up of several different materials: |
|
Definition
| Homogenous each layer or material will need to be examined |
|
|
Term
| If no fibers are present under the Stereo or PLM which test would be used next? |
|
Definition
The pinch test
(, additional searches for small
asbestos fibres on random sub-samples of a few milligrams are undertaken using PLM ) |
|
|
Term
what is recommended for temporary containment of
sample waste before final disposal |
|
Definition
| Heavy-duty plastic bags in correctly labeled bags |
|
|
Term
| Where must stereo-microscope examinations and sample preparation be executed |
|
Definition
| a fume cupboard, or in a suitable cabinet |
|
|
Term
| What is the minimum face velocity of fume cabinets |
|
Definition
| 0.5 m/s over the working area |
|
|
Term
What class vacuum cleaner is also recommended for emergency clean-up and cleaning up spills
inside the cabinet |
|
Definition
|
|
Term
| Apparatus required for sample preparation? |
|
Definition
probes, needlepoint tweezers and fine
tungsten needles |
|
|
Term
| Pre-treatment apparatus may include? |
|
Definition
glass beakers, disposable or washable glass
Petri dishes or containers, an ultrasonic bath, boiling tubes, vacuum filtration flask, pump and filter
holder with appropriate filters, |
|
|
Term
| What may be needed to break samples |
|
Definition
Pliers, a file, a hammer and a saw may be needed to break samples a pestle and mortar may be used to
grind samples and release fibres from matrices. |
|
|
Term
| What happens to wet samples in sample prep |
|
Definition
Wet samples may be dried using a hot plate, oven,
infra-red lamp or by flushing through with acetone |
|
|
Term
| What equipment is needed for PLM Analysis |
|
Definition
glass slides, coverslips, probes
and tweezers of appropriate quality are required including PLM Microscope and RI liquids |
|
|
Term
What equipment is used to assess whether organic
fibres and spider’s webs are present? |
|
Definition
|
|
Term
| What is a homogeneous sample |
|
Definition
|
|
Term
| What is the process with non-homogeneous samples |
|
Definition
Record sample as non-homogeneous then describe each individual layer by colour,
texture, and if possible, material type). Take sub-samples if necessary |
|
|
Term
| What is the magnification of a stereo microscope |
|
Definition
|
|
Term
| What are the two slides on the PLM microscope used for analysis that are removable |
|
Definition
| a removable analyser and a removable first-order red compensator |
|
|
Term
What following accessories are required to aid the assessment of fibre RIs by producing
intense dispersion staining colours |
|
Definition
a phase contrast objective (10x magnification or greater) and condenser with matching centrable phase annuli
or a dispersion staining objective (10x magnification) with a central stop in its back focal plane, used
in conjunction with the condenser iris |
|
|
Term
What type of illumination is needed
for fibre identification: |
|
Definition
|
|
Term
What products, may contain asbestos
fibres that are too fine to be detected in this
initial examination |
|
Definition
products such as decorative plasters, vinyl floor
tiles, and settled dusts |
|
|
Term
| what determines the sample treatment that is required to help isolate the fibers from the other components |
|
Definition
| The product type determined by The appearance, colour and texture of the sample, and any fibre types observed |
|
|
Term
| Do you have to do sample preparation in a sample where no fibres are present but is a material/product type that is known to have the potential to contain asbestos |
|
Definition
| One or more sample prep techniques should be carried out |
|
|
Term
| What type of sample prep is recommended for loose fibre, sprayed coatings and textiles |
|
Definition
| Usually sample prep isn't required |
|
|
Term
| What type of sample prep is recommended for lagging? |
|
Definition
| Breaking and treat with dilute HCl |
|
|
Term
What type of sample prep is recommended for Asbestos insulating board (AIB), asbestos
cement (AC) and millboard |
|
Definition
|
|
Term
| What type of sample prep is recommended for Decorative plaster, textured decorative coatings |
|
Definition
| Breaking and acid treat with dilute HCl |
|
|
Term
| What type of sample prep is recommended for Mastics and adhesives |
|
Definition
| Breaking, solvent treatment (acetone) and/or combustion |
|
|
Term
| What type of sample prep is recommended for Floor tile |
|
Definition
| Breaking and solvent treatment or combustion |
|
|
Term
| What type of sample prep is recommended for Vermiculite |
|
Definition
| Combustion/heating and/or acid/alkali digestion/sedimentation |
|
|
Term
| What type of sample prep is recommended for wet samples |
|
Definition
| May be searched while damp but dry fibres are required for PLM analysis (heat lamp) |
|
|
Term
| Which bit of the sample may be inspected under the stereo microscope after breaking |
|
Definition
The newly fractured edges should be inspected
under the stereo-microscope for the presence of protruding fibres, which are carefully removed and
mounted in an appropriate RI liquid for PLM analysis |
|
|
Term
| What types of acid are used in sample prep |
|
Definition
| Dilute acetic acid (eg 50%) or cold dilute hydrochloric acid (eg 10%) |
|
|
Term
| What do you wash the sample with after acid treatment to reduce drying time |
|
Definition
|
|
Term
| The acid is used to remove: |
|
Definition
e calcium carbonate, calcium sulphate and calcium silicate, which are
common binders in insulation and asbestos boards, and which are used as fillers in floor tiles |
|
|
Term
| Fibre release when treated with acid may be aided by |
|
Definition
| stirring, crushing with a suitable tool or by ultrasonic treatment |
|
|
Term
| Solvent treatment works on... |
|
Definition
Organic binders (eg in plastics, bitumen, resin or rubber products)
may require prolonged treatment in solvents |
|
|
Term
| Ashing/combustion treatment is used to remove...? |
|
Definition
|
|
Term
| What can be used for ashing/combustion treatment |
|
Definition
| 400°C in a furnace/oven or using a spirit lamp or a lighter |
|
|
Term
| How can you do Disaggregation treatment |
|
Definition
These can be removed by various
treatments eg. placing in denatured alcohol,
or using pressure on the coverslip to separate fine attached particles in the RI liquid |
|
|
Term
|
Definition
allows particle size separation to take place and various
fractions to be selected for more detailed analysis. Some materials and particles can also be separated by flotation |
|
|
Term
| Commonly known as White asbestos |
|
Definition
|
|
Term
| Commonly known as Brown Asbestos |
|
Definition
|
|
Term
| Commonly known as Blue asbestos |
|
Definition
|
|
Term
Soft with bundles
of sinuous fibres |
|
Definition
|
|
Term
Soft or harsh; may appear as easily visible
parallel fibre bundles |
|
Definition
| Amosite, Anthophyllite, and Tremolit |
|
|
Term
| Asbestos types with Soft or harsh with parallel fibre bundles |
|
Definition
| Actinolite and Crocidolite |
|
|
Term
|
Definition
|
|
Term
|
Definition
| Amosite and Anthophyllite |
|
|
Term
|
Definition
|
|
Term
| Vitreous/green/grey Lustre |
|
Definition
|
|
Term
| Metallic (dark and highly reflective) Lustre |
|
Definition
|
|
Term
|
Definition
| Chrysotile, Amosite and Crocidolite |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| RI Liquid for Anthophyllite |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| RI Liquid for Crocidolite |
|
Definition
|
|
Term
| inelastic type of asbestos |
|
Definition
|
|
Term
|
Definition
| Amosite, Anthophyllite, Tremolite, Actinolite, and Crocidolite |
|
|
Term
| Before mountain in RI liquid fibres should be |
|
Definition
| dry and relatively free from other particulate matter |
|
|
Term
| Trace asbestos term can be used when |
|
Definition
| during the search of the two ‘pinch’ samples by PLM only 1 or 2 fibres (or fibre bundles) are seen and identified as asbestos |
|
|
Term
| How long should you look under the Stereo Microscope? |
|
Definition
|
|
Term
| In the pinch test what is the minimum time you should look under the PLM Microscope |
|
Definition
| 5 minutes per mounted microscope slide where there is at least two extracted preporations |
|
|
Term
| asbestos not detected’ should be reported when... |
|
Definition
No asbestos fibres or fibre bundles
are identified after areful searching of the sample under the stereo-microscope for around 10 minutes; and subsequent searching a minimum of two extracted preparations mounted in suitable RI
liquid at high magnification by PLM/PCM for a further 5 minutes. |
|
|
Term
| Why must a number of optical properties be assessed to identify a particle |
|
Definition
The optical properties viewed will depend on fibre type and particle orientation which may differ due to The exact arrangement of the silica tetrahedra and the type of cations in the structure
will change the interactions (optical properties) between the crystal structure and the light rays transmitted through them |
|
|
Term
| What settings are needed on the PLM to test pleochroism |
|
Definition
| plane-polarised light conditions - polariser only (no analyser or 1st order red compressor) |
|
|
Term
| what do you look for when the PLM is set up for Plane-polarised light (polariser only) |
|
Definition
| Colour and pleochroism (if present) |
|
|
Term
| what do you look for when the PLM is set up for Polarised light/crossed polars polariser and analyser) |
|
Definition
Birefringence (anisotropic behaviour)
Extinction characteristics |
|
|
Term
| what do you look for when the PLM is set up for Crossed polars with first-order red compensator |
|
Definition
|
|
Term
| what do you look for when the PLM is set up for using a phase contrast, or dispersion staining objective with polariser only |
|
Definition
| Refractive index by dispersion staining colours |
|
|
Term
| Which asbestos type has blue/grey pleochroism? |
|
Definition
|
|
Term
| Which asbestos type has Green/grey pleochroism? |
|
Definition
|
|
Term
| Which two asbestos types don't have moderate Birefringence and which type do they have? |
|
Definition
Chrysotile - Low
Crocidolite - Low/anomalous |
|
|
Term
| Which Asbestos type has Complete, or undulose with curved fibres; parallel extinction |
|
Definition
|
|
Term
| Which aspestos types have Complete parrallel or small angle extinction? |
|
Definition
|
|
Term
| Which type of asbestos has a negative fast sign of elongation |
|
Definition
|
|
Term
| Why may sign of elongation change in asbestos types? |
|
Definition
|
|
Term
| Chrysotile dispersion staining objective colours |
|
Definition
|
|
Term
| Amosite dispersion staining objective colours |
|
Definition
|
|
Term
| Anthophyllite dispersion staining objective colours |
|
Definition
|
|
Term
| Tremolite dispersion staining objective colours |
|
Definition
|
|
Term
| Actinolite dispersion staining objective colours |
|
Definition
| Red- Orange - yellow/ Blue - Purple |
|
|
Term
| Crocidolite dispersion staining objective colours |
|
Definition
|
|
Term
| What is the Birefringence |
|
Definition
| The numerical difference between the highest and lowest RIs of a mineral is known as the birefringence |
|
|
Term
| Why does Crocidolite have an anomalous interference colours from grey to pale blue or sometimes brown |
|
Definition
Crocidolite has a low birefringence and strong pleochroism (blue colour) which results in
anomalous interference colours from grey to pale blue or sometimes brown. |
|
|
Term
|
Definition
Extinction is caused
when a vibration direction within the fibre/particle is in alignment with the vibration direction of the
illuminating rays. All light is transmitted without alteration as a single refractive index and hence,
when it meets the analyser, it is stopped |
|
|
Term
| where will crossed polars 'extinguish' |
|
Definition
at four positions each 90° apart, while at
45° between each extinction position, interference colours should be visible |
|
|
Term
| When is a fibre described as positive or length slow |
|
Definition
| If the high RI vibration plane (slow ray) is parallel to the long axis, then the fibre is described as positive |
|
|
Term
| When is a fibre described as negative or length fast |
|
Definition
| if the low RI vibration plane (fast ray) is parallel to the long axis, the fibre is described as negative (or length fast) |
|
|
Term
| What may change the sign of elongation |
|
Definition
exposure to heat of about 300°C or higher may change the sign
of elongation of crocidolite to positive (length slow) |
|
|
Term
| What is the refractive index (RI) |
|
Definition
is the ratio of the speed of light in a vacuum to the speed of light in that substance and is
generally quoted for the sodium D line (nD) at 589 nm |
|
|
Term
| Why do crystalline materials have more than one refractive index |
|
Definition
Most crystalline
materials have more than one refractive index because the atoms are packed in a different array along the three crystal axes |
|
|
Term
| One or more observations are conducted to determine whether the RI of the fibre is higher than, lower than or equal to that of the mounting liquid by... |
|
Definition
Relief
Becke line
Dispersion Staining colours |
|
|
Term
|
Definition
high relief denotes high contrast
and, conversely, low relief denotes low contrast |
|
|
Term
| What colour appears when the particle and mount are a long way from RI match point |
|
Definition
| White (saturated colours on a black background) |
|
|
Term
| What colour appears when the RI of the mounting liquid is too high |
|
Definition
| a pale blue colour (saturated colours on a black background) |
|
|
Term
What colour appears when a higher RI mount should be used to achieve a match in
the visible spectrum. |
|
Definition
| a pale yellow colour indicates (saturated colours on a black background) |
|
|
Term
| What was Chrysotile most used in |
|
Definition
| cement and textile products |
|
|
Term
| What was crocidolite most used in |
|
Definition
| insulation and as a spray coating due to its thermal properties |
|
|
Term
| What is Amosite most used in |
|
Definition
| board products and ceiling tiles |
|
|
Term
| How many deaths are caused by asbestos annually |
|
Definition
|
|
Term
| How many buildings are predicted to still contain asbestos? |
|
Definition
| between 500,000 and 2m commercial premises and around 2.5m domestic dwellings |
|
|
Term
| What risk is determined largely by asbestos exposure before age 30 |
|
Definition
|
|
Term
| Why are carpenters at a particularly high risk? |
|
Definition
| exposure to amosite while cutting AIB |
|
|
Term
| Which asbestos type is hydrophilic |
|
Definition
|
|
Term
| what % asbestos fibre does 'limpet' or sprayed asbestos-cement have in it |
|
Definition
|
|
Term
|
Definition
| high content and high friability |
|
|
Term
| when was the statutory ban on brown and blue asbestos |
|
Definition
|
|
Term
| when was the statutory ban on white asbestos |
|
Definition
|
|
Term
| What risk is thermal insulation regarded as |
|
Definition
|
|
Term
| What content did thermal insulation have of asbestos |
|
Definition
|
|
Term
| What type of asbestos did thermal insulation contain |
|
Definition
| blue, brown or white asbestos |
|
|
Term
|
Definition
|
|
Term
| What percentage content of asbestos is in AIB |
|
Definition
|
|
Term
| What risk is asbestos cement |
|
Definition
|
|
Term
| What abestos content is usually n asbestos cement |
|
Definition
|
|
Term
| What makes asbestos cement low risk |
|
Definition
lower content, its low friability as very dense and fibres firmly bound in cement matrix and it was usually only white asbestos used.
It is very resistant to weathering and With the material predominantly being used externally,
any fibre release is immediately diluted in atmosphere. |
|
|
Term
| What are the three main diseases caused by asbestos |
|
Definition
Asbestosis. Scarring or fibrosis of the lung.
Mesothelioma. Cancer of the pleura or peritoneum.
Asbestos related lung cancer |
|
|
Term
| What are three benign conditions |
|
Definition
Pleural plaques
Pleural thickening and effusions
Asbestos warts and corns |
|
|
Term
| What are the three main determinants of risk |
|
Definition
a) Ease of fibre release (loosely or firmly bound)
b) % content of fibre in the product itself
c) Type of fibre – blue brown and white. |
|
|
Term
What does this list display
1. Sprayed coatings
2. Insulation
3. Asbestos insulating board (AIB)
4. Asbestos cement (AC)
5. Textiles
6. Composites |
|
Definition
| asbestos products in descending order of risk |
|
|
Term
| What is the control limit of asbestos |
|
Definition
| 0.1 f/cm3 (same as f/ml) averaged over a continuous 4 hour period |
|
|
Term
| What is the exposure Limit of Sporadic and low intensity exposure |
|
Definition
| 0.6 f/cm3 over 10 minutes |
|
|
Term
| What are some controls if the work area is over the control limit |
|
Definition
The work must be notified to HSE / Local Authority
All employees undertaking this work must be under
medical surveillance and their exposure should be monitored
eating, drinking
and smoking in this area is prohibited
decontamination unit (DCU) and the employer must minimise the
number of people entering the area |
|
|
Term
| What is the Clearance indicator |
|
Definition
“Lowest level reliably detectable above
background”. This level has no relation to “safety” |
|
|
Term
| Typical compositions of spray coating |
|
Definition
| 85% crocidolite or amosite or amosite + chrysotile mixture |
|
|
Term
| Typical Composition Pipe insulation - hard set |
|
Definition
| up to 70% of all or any mixture of asbestos types other non-asbestos fibres (hair, straw, wood, cotton) |
|
|
Term
| Typical Composition Pipe insulation – sectional |
|
Definition
| 15 to 60% amosite mainly, but also mixtures |
|
|
Term
| Typical composition Asbestos cement |
|
Definition
| 10 - 15% chrysotile may rarely find Amo and Croc |
|
|
Term
| Typical composition Asbestos insulating board (AIB) |
|
Definition
15 - 25% amosite (earlier up to 40%)
• may contain some chrysotile in combination with amosite
• can be crocidolite alone |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| Rope or textiles composition |
|
Definition
100% chrysotile or blended with synthetic
organic or cellulose fibres |
|
|
Term
| Eternit window boards composition |
|
Definition
|
|
Term
| Toilet cisterns compsition |
|
Definition
| 10% amosite (chrysotile and/or crocidolite) |
|
|
Term
| Textured coatings composition |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| the numerical difference between the highest and lowest RI along three axes |
|
|
Term
|
Definition
length slow or positive sign
of elongatio |
|
|
Term
|
Definition
| length fast or negative sign of elongation |
|
|
Term
|
Definition
When a fibre is rotated at 45º it appears white to grey At vertical and horizontal (parallel to planes of polarisation) it is
‘extinguished’ |
|
|
Term
Crocidolite often shows ... under
crossed polars |
|
Definition
| ‘anomalous interference colours’ |
|
|
Term
Crocidolite often shows ... under
crossed polars |
|
Definition
| ‘anomalous interference colours’ |
|
|
Term
|
Definition
Normally optical plane coincides with geometric plane
Fibre is ‘extinct’ parallel to planes of polarisation
For some crystal systems the optical plane is inclined to the crystal
plane |
|
|
Term
| angle of extinction Chrysotile, amosite and crocidolite |
|
Definition
|
|
Term
| angle of extinction Tremolite and actinolite |
|
Definition
oblique extinction angles
• may be difficult to observe, HSG 248 says ‘parallel or small
(5º) angle of extinction’ |
|
|
Term
| Angle of extinction Anthophyllite |
|
Definition
| orthorhombic and always parallel extinction |
|
|
Term
| How is the z´/ g direction always aligned and marked |
|
Definition
|
|
Term
| What colour would you expect to see Slow directions parallel |
|
Definition
|
|
Term
| What colour would you expect to see Slow directions perpendicular |
|
Definition
|
|
Term
|
Definition
| Differential absorption of visible wavelengths with orientation in plane polarised light |
|
|
Term
| pleochroic types of asbestos |
|
Definition
| crocidolite and actinolite |
|
|
Term
|
Definition
| White fringe at particle interface with liquid of different RI |
|
|
Term
|
Definition
| Intersection points represent wavelengths (colours) at which particle and fibre match exactly - λ0 |
|
|
Term
| When looking at the McCrone Objective if RI fibre > RI liquid what colou would you expext |
|
Definition
|
|
Term
| When looking at the McCrone Objective if RI fibre < RI liquid whqt colour would you expect |
|
Definition
|
|
Term
| Chrysotile dispersion colours can depend on |
|
Definition
source and history (acid treatment or weathering)
Classically: blue to purple |
|
|
Term
| Organic fibres which may mimic chrysotile |
|
Definition
Leather
• Polypropylene or polyethylene
• Spiders’ web
• Paper swarf
• Feathers? |
|
|
Term
| What would you do if you didn't know if a fibre was asbestos or another material |
|
Definition
|
|
Term
|
Definition
any flat sheet, tile or building board consisting of a
mixture of asbestos and other material except asbestos
cement |
|
|
Term
|
Definition
“asbestos cement is a material which is predominantly a
mixture of cement and chrysotile which absorbs less than 30%
water by weight |
|
|
Term
| How to test if the sample is AIB or AC |
|
Definition
|
|
Term
| What is the Water Absorption Test process |
|
Definition
Take a 3 x 3cm sample
Dry it and weigh it
Immerse in water for 15 mins
Remove and re-weigh
If weight of water absorbed is <30% of original weight, report as AC
If >30% report as AIB |
|
|
Term
| How many samples can you have in a cabinet at any time |
|
Definition
| One sample only in cabinet at any one time |
|
|
Term
| What is the aim of sample handling |
|
Definition
| to prevent cross-contamination |
|
|
Term
| Where can sample bags be opened |
|
Definition
|
|
Term
| What should you check on the cabinet before use |
|
Definition
| Check airflow – should be 0.5 to 1.0 m/sec |
|
|
Term
| How often does air testing in lab need to be held |
|
Definition
|
|
Term
| Where must chemicals be kept |
|
Definition
should be kept in lockable metal cabinet and decanted
into smaller containers for use in cabinet |
|
|
Term
| When must cabinmates be cleaned |
|
Definition
| preferably between samples but especially at the end of the day using type-H vacuum |
|
|
Term
| How must waste be removed |
|
Definition
| via red bags and licensed contractor |
|
|
Term
| When does pleochroism develop within amosite |
|
Definition
|
|
Term
| What happens to Croc and Amo after being exposed to temps over 500°C |
|
Definition
| effectively indistinguishable by light microscopy as RIs are greater than 1.700 |
|
|
Term
| What happens to chrysotile after being exposed to heat over 600°C |
|
Definition
the birefringence decreases and the fibres become pale yellow-brown
changes the sign of elongation to negative (length fast) when the RI changes to above 1.640 |
|
|
Term
| What happens to the RI of the asbestos when there is heat damage |
|
Definition
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Term
| The purpose of a QA programme |
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Definition
sampling, analysis, recording and
reporting of the results all meet acceptable standards |
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Term
| What percentage of samples should be routinely checked for QC |
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Definition
| 5% of re-analyses on new samples should be maintained (ie the samples analysed up to the maximum number of 20 and 40 |
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Term
| What is the maximum points or samples done within 24 hours |
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Definition
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Term
| maximum number of samples from category A (ACM) until additional QC applies |
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Definition
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Term
| maximum number of samples from category B (No asbestos detected and harder to detect materials) until additional QC applies |
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Definition
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Term
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Definition
| hazard placard to be displayed on the sealed asbestos container |
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Term
| Limited quantities exemptions or, in specific cases, the bonded materials Asbestos can be contained within: |
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Definition
| samples should be double-bagged (with the bags individually sealed) and then placed in an allowed outer packaging which bears the asbestos warning label |
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Term
| What should asbestos waste bear |
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Definition
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Term
Where should asbestos be binned when it contains 0.1% w/w or more asbestos or
a piece of asbestos large enough to be visible to the naked eye |
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Definition
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Term
| When is asbestos hazardous waste |
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Definition
| After they have been analysed |
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Term
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Definition
A microscope objective in which chromatic aberration is
minimised for two wavelengths (one less than about 500 nm,
and the other greater than about 600 nm), and spherical
aberration and other aperture-dependent effects are
minimised for another wavelength (usually about 550 nm). |
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Term
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Definition
A polar used after the object (usually between the objective
and the primary image plane) to determine optical effects
produced by the object on the light, polarised or otherwise,
with which it is illuminated. |
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Term
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Definition
A bright line (due to refraction and/or diffraction) formed in
the image at the boundary between media of different
optical path lengths. It moves in the direction of the longer
optical path when the distance between the objective and
the object is increased. (Note: this phenomenon is used to
recognise relative differences in Rl of two adjacent media,
eg a particle and the surrounding medium; when the Rls are
matched the Becke line disappears.) |
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Term
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Definition
An intermediate lens which transfers an image of the back
focal plane of the objective into the primary image plane;
used for conoscopic observation in polarised light microscopy
and for adjustment of the microscope illumination system,
especially with phase contrast microscopy. |
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Term
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Definition
| The qualitative expression of the maximum difference in Rl due to double refraction (symbol n) |
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Term
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Definition
| A retardation plate (sometimes of variable optical path length difference) used to measure the optical path length differences within an object |
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Term
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Definition
A part of the illumination system of the microscope which
consists of one or more lenses (or mirrors) and their mounts,
usually containing a diaphragm, and is designed to collect,
control and concentrate radiation |
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Term
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Definition
The condition in which the vibration directions of polars
(polariser and analyser) are mutually perpendicular. |
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Term
| Dispersion-staining microscopy |
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Definition
The microscopy of transparent objects that are in a mounting
medium, the Rl of which matches that of the object for a
certain wavelength, but which has a distinctly higher
dispersive power than the object. Under these conditions both
the object and the mounting medium appear coloured near
their interfaces. The colour with which the object appears is
distinctly different from that with which the mountant
appears. The colours and their differences depend on the
wavelength at which the Rls of the object and medium match
and the kind of microscopy used; dispersion staining may be
used in bright-field microscopy, the colour being concentrated
in the Becke line, in darkground microscopy or in phasecontrast microscopy |
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Term
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Definition
A lens system that is responsible for the angular
magnification of the final virtual image formed by it from the
primary image. This image is converted into a real image by
the observer’s eye or other converging lens system |
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Term
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Definition
Red, first-order (sensitive tint): the characteristic reddish violet
interference colour at approximately 530 nm retardation |
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Term
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Definition
(1) A surface connecting all the points at which bundles of
parallel rays entering an ideal converging lens cross on the
other side of the lens, and thus containing a focal point; (2)
a surface at right angles to the optical axis of a lens (or
mirror) in which the image of an object lying at infinity is
formed: it is one of the cardinal planes |
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Term
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Definition
An eyepiece with a mechanism for focusing an
(interchangeable) graticule or diaphragm mounted within it
and coinciding with the primary image. |
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Term
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Definition
A diaphragm bounded by multiple leaves, usually metal,
arranged so as to provide an opening of variable size which
is adjustable by means of a control |
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Term
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Definition
| A mixed colour resulting from extinction or partial extinction caused by interference of one or several parts of a spectrum |
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Term
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Definition
| A method of illuminating objects in which an image of the source is projected by a collector into the plane of the aperture diaphragm in the front focal plane of the condenser. This latter, in turn, projects an image of an illuminated field diaphragm at the opening of the collector into the object plane |
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Term
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Definition
A number (often symbolised by the letters NA) originally
defined by Abbé for objectives and condenser. It is given by
the expression ‘n × sin u’, where ‘n’ is the Rl of the medium between the lens and the object and ‘u’ is half the angular aperture of the lens. |
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Term
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Definition
| The first part of the imaging system, consisting of a lens, its mount, and any associated parts. It forms a primary image of the object. |
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
| If a mineral has a refractive index that is much higher or lower than the surrounding materials, it will stand out relative to the surrounding material and will have thick or distinct |
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Term
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Definition
| as it is a shorter wavelength than yellow |
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