Asbestos Types, Uses, Health Effects and Legislation — Royal Society for Public Health Vocationally-Related Qualification Construction & Building Services Revision
This subtopic covers the identification and classification of the six regulated asbestos fibre types, focusing on the three most common commercial forms: c
Topic Synopsis
This subtopic covers the identification and classification of the six regulated asbestos fibre types, focusing on the three most common commercial forms: chrysotile, amosite, and crocidolite. Learners must understand their distinct physical and chemical properties, historical uses in construction, and the severe health consequences of exposure including asbestosis, lung cancer, and mesothelioma. The content also addresses the legislative framework, particularly the Control of Asbestos Regulations 2012, covering duty to manage, licensing, notification, and training requirements to ensure safe work practices.
Key Concepts & Core Principles
- Four-stage clearance procedure: Stage 1 – Preliminary check of enclosure and decontamination unit; Stage 2 – Thorough visual inspection; Stage 3 – Reassurance air sampling (if required); Stage 4 – Final air sampling and clearance certification.
- Air sampling methods: Background (prior to removal), reassurance (during removal), and clearance (after removal) using a pump calibrated to 2 litres per minute with a 25mm diameter filter cassette.
- Fibre counting and analysis: Using phase contrast microscopy (PCM) to count fibres that meet the World Health Organization (WHO) criteria (length >5µm, width <3µm, aspect ratio >3:1).
- Control limit and clearance indicator: The control limit is 0.1 fibres per millilitre (f/ml) over a 4-hour period; for clearance, the area must have a fibre concentration below 0.01 f/ml (the clearance indicator) based on a minimum of four samples.
- Documentation: Completing a certificate of reoccupation (CoR) and maintaining records of air monitoring results, including chain of custody for samples.
Exam Tips & Revision Strategies
- Memorise the key dates and titles of major asbestos legislation, particularly the Control of Asbestos Regulations 2012 and its associated Approved Codes of Practice.
- Use case studies or examples of historical applications to demonstrate understanding of why particular asbestos types were used in specific building materials.
- Ensure you can clearly differentiate between the health effects, linking each disease to the type of exposure (e.g., occupational, environmental) and typical fibre type where relevant.
- When answering questions on legislation, always reference the duty to manage and the requirement for asbestos surveys, highlighting the roles of duty holders and licensed contractors.
Common Misconceptions & Mistakes to Avoid
- Confusing the properties of different asbestos types, such as believing chrysotile is harmless or that amosite and crocidolite share identical risk levels.
- Misidentifying the uses of asbestos, for example, stating that crocidolite was commonly used in textured coatings, when in fact it was typically used in cement products and insulation.
- Quoting outdated or repealed legislation, such as the Asbestos (Prohibitions) Regulations 1992, rather than the current Control of Asbestos Regulations 2012.
- Failing to distinguish between the specific health effects: asbestosis (chronic scarring), lung cancer, and mesothelioma, often attributing all to a single exposure mechanism.
Examiner Marking Points
- Award credit for correctly naming and distinguishing the three main commercial asbestos types (chrysotile, amosite, crocidolite) with reference to colour, fibre structure, and typical applications.
- Credit should be given for accurately describing the latency period and pathogenesis of asbestos-related diseases, linking specific fibre types to conditions like mesothelioma or asbestosis.
- Assessors must look for precise identification of key legislation, including the Control of Asbestos Regulations 2012, and demonstration of understanding of duty holder responsibilities and the difference between licensable and non-licensable work.