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BOHS P401 Identification of Asbestos in Bulk Samples (PLM)
Course
In Southend-On-Sea ()
Description
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Type
Course
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Duration
3 Days
Reviews
Course programme
Content: Classroom theory and practical, course notes for all delegates, visual aids/equipment
ITINERARY
1. ASBESTOS FIBRES
- Asbestos
- Uses of Asbestos
- Health Effects of Asbestos
2. SET UP AND USE OF A POLARISED LIGHT MICROSCOPE
- Equipment and use
- Theory
- Observations
3. ANALYSIS OF BULK SAMPLES
- Microscopic examination
- Sample Preparation
- Dispersion Staining
- Safety During Identification
- Quality Control
- Interfering fibres and products
4. PRACTICAL WORK
NB. Group/syndicate exercise will form part of the programme. The programme above does not reflect total content of material covered. A full agenda and itinerary will be sent two weeks prior to commencement of the course.
Please note that the exam delegate fee is NOT included in this price and must be paid for seperately.
CONTENT:
TOPIC TIME ALLOCATION
1. ASBESTOS FIBRES 5
2. SET UP AND USE OF A POLARISED LIGHT MICROSCOPE 15
3. ANALYSIS OF BULK SAMPLES 40
4. PRACTICAL WORK 40
Note: Reference is made in this syllabus to HSE guidance or other documentation. This may not be the most upto- date relevant publications from HSE/other sources and is intended as guidance for candidates only.
1. ASBESTOS FIBRES (5%)
1.1 Asbestos
Describe the 6 regulated forms of asbestos in relation to the serpentine and amphibole groups of minerals.
Discuss their characteristic properties, such as flexibility, tensile strength, combustibility, thermal
conductivity and resistance to chemical attack. Describe the effects of thermal and other forms of
degradation on asbestos minerals.
1.2 Uses of Asbestos
Explain the physical and chemical properties of asbestos which have determined the use to which it has
been put by industry. Discuss the three types of asbestos which have found significant commercial use
(amosite, chrysotile and crocidolite) and the types of materials they were added to. Describe the use and
occurrence of the other types of asbestos particularly as possible contaminants in other minerals.
1.3 Health Effects of Asbestos
Describe the full range of health effects ranging from the benign (pleural plaques) to the terminal
(mesothelioma) in the light of results from epidemiological studies carried out on asbestos workers.
Educational Objectives
The student must have a good knowledge of the types and forms of asbestos fibres and their industrial uses.
2. SET UP AND USE OF A POLARISED LIGHT MICROSCOPE (15%)
2.1 Equipment and use
Review the minimum equipment required. Discuss and demonstrate alignment of the optics and obtaining
Koehler or Koehler type illumination. Discuss and demonstrate the alignment and use of the rotating stage,
polarisers and cross-hair eyepieces, field and sub-stage diaphragms, phase and dispersion staining
objectives.
2.2 Theory
Discuss the theory of polarised light and the effects produced on crystalline and amorphous or vitreous
materials. Cover the basic physics behind colour, pleochroism, birefringence (interference colours), sign of
elongation and extinction.
2.3 Observations
Demonstrate the occurrence of colour, pleochroism, birefringence (interference colours), sign of elongation
and extinction. Discuss and demonstrate the use and effects of refractive index oils and the use of Becke
line and dispersion observations.
Educational Objectives
The student must know the theory of polarised light and the practicalities involved in setting up and using a
polarised light microscope.
3. ANALYSIS OF BULK SAMPLES (40%)
3.1 Macroscopic examination
Using HSG248 (1) as a basis, demonstrate examination by low power stereo microscope, including the
recognition of the basic physical properties of the main asbestos types i.e. colour, lustre, elasticity, tenacity, morphology and behaviour in water.
3.2 Sample Preparation
Explain and demonstrate the options for sample preparation to segregate the asbestos for analysis. Using
HSG248 (1) as a basis, demonstrate sample preparation methods to remove matrix materials before PLM
identification, including acid washing, solvent extraction and combustion.
3.3 Polarised Light Microscopy
Examine using polarised light microscopy characteristics such as morphology, colour, pleochroism,
birefringence (interference colours), sign of elongation and extinction of different asbestos types.
3.4 Dispersion Staining
Describe and demonstrate dispersion stain microscopy using R.I. liquids together with a McCrone
dispersion staining objective or phase contrast microscopy with polariser in relation to the assessment of
refractive indices of asbestos and other fibres.
3.5 Safety During Identification
Discuss the safety precautions required when working with asbestos and other fibres e.g. the use of glove
boxes and ventilated cabinets as well as the required precautions when using acids during sample
preparation and when handling R.I. liquids. This must include the routine inspection/checking of ventilation
and control systems as required under CAR/COSHH regulations.
3.6 Quality Control
Discuss Quality Control procedures, likely detection limits, problems of cross contamination during
sampling and analysis, together with the handling of homogeneous and heterogeneous samples. External
proficiency schemes such as AIMS.
Discuss the problems associated with fatigue and eye strain and how to minimise them.
3.7 Interfering fibres and products
Describe the other types of fibres which may interfere with asbestos identification e.g. leather swarf, skin
cells, polyethylene. Problems with other products such as floor tiles. The effects of heat on asbestos
fibres.
Educational Objectives
The student must be able to describe the approved methods for analysis of bulk fibre samples and have an
understanding of the exposure controls and quality controls required during this activity.
4. PRACTICAL WORK (40%)
Practical work must be carried out to provide the student with all practical knowledge in carrying out the
following:
• microscope set-up
• sample preparation
• PLM typing of unknown samples
• Identification of asbestos using polarised light dispersion staining techniques.
COURSE LENGTH
It is envisaged this course would be run over 2 days with a further ½ day for the examination and assessment.
REFERENCES
(1) HSE Guidance HSG248 (2005) Asbestos: The Analyst’s guide for sampling, analysis and clearance
procedure.
COURSE EXAMINATION/ASSESSMENT
The students would be assessed as follows:
• A 45 minutes MCQ BOHS examination (25 questions).
• A practical assessment, which involves the identification of unknown samples supplied by BOHS and
carried out by an approved practical assessor as follows:
PRACTICAL ASSESSMENT - ASBESTOS IDENTIFICATION
Assessment must include:
• Identification of 6 unknown samples - A full marking schedule based on HSL scoring is used
• Observation of safety protocols
• Evaluation/checking of working environment control systems
• Evaluation of competence in use of microscopes
Full details of the practical assessment requirements are provided as a separate document GA.2 P401
Practical Requirements
Successful completion of the above will lead to a:
‘PROFICIENCY CERTIFICATE’ in IDENTIFICATION OF ASBESTOS IN BULK SAMPLES (PLM)
Additional information
BOHS P401 Identification of Asbestos in Bulk Samples (PLM)