Asbestos: The analysts' guide for sampling, analysis and clearance procedures
 HSE(英国健康安全局、Health and Safety Excutive)による。

This is a free-to-download, web-friendly version of HSG248 (First edition, published 2006). This version has been adapted for online use from HSE’s current printed version.


1 Introduction 4
2 Quality assurance and accreditation schemes 7
3 Training and qualifications 8
4 Sampling and analysis of materials for the presence of asbestos 10
5 Sampling and analysis of airborne fibre concentrations 17
6 Site assessment for reoccupation 26
7 Supervisory work carried out by analysts 39
8 Personal protective equipment 41
9 Decontamination procedures 48

1 Fibres in air: Sampling and evaluation of by phase contrast microscopy 56
2 Asbestos in bulk materials: Sampling and identification by polarised light microscopy (PLM) 81
3 Template for certificate of reoccupation 107
4 Template for the inspection certificate for the hygiene facility 112
References and further information 115
Glossary of acronyms 120

1 Introduction

What does this guidance do?
1.1 This publication consolidates and updates technical guidance from a number of HSE sources, including previously published guidance notes (EH10, MDHS39, MDHS77), which it now replaces. It mainly deals with analysts involved in licensed asbestos removal and sampling of asbestos-containing materials (ACMs). Simpler procedures are applicable for small scale and short-term asbestos removal work (Asbestos essentials)1 and for ACMs which do not require a licence, eg asbestos cement (HSG189/2). In addition, the publication links in with guidance produced for licensed removal contractors entitled Asbestos: The licensed contractors’ guide. This publication contains guidance on:
■quality assurance;
■training for analysts;
■bulk sampling and analysis;
■air sampling and analysis;
■site certification for reoccupation;
■supervisory work;
■personal protective equipment; and
■decontamination procedures.

1.2 Appendix 1 contains details of the future approved analytical method for the evaluation of fibres in air. Amendments to the European Worker Protection Directive to be implemented by 2006 will replace the existing European Reference Method (see MDHS39/4) with the World Health Organisation (WHO) method. The updated method has been included to allow analysts to become familiar and train with the new method but MDHS39/45 should continue to be used until the new EU directive is implemented. Appendix 2 gives the analytical method for the identification of asbestos fibres in materials and contains the same advice as the last version of MDHS77.

1.3 Although this guidance covers sampling and analysis of suspected ACMs, it does not go into detail about surveying and assessment of premises for ACMs. Surveying is covered in depth in MDHS1008 and further guidance on the assessment and management of asbestos in buildings is given in HSG227.

Who is this guidance for?
1.4 This guidance is designed for a technical audience, eg asbestos analysts, asbestos consultants, occupational hygienists, safety officers etc. It will also be useful to asbestos removal contractors and supervisors, employers, building owners and people with responsibility for managing properties and estates.

1.5 The Control of Asbestos at Work Regulations 2002 (CAWR) applies to all work activities involving asbestos-containing materials. It places duties on an employer, including the self-employed, who carries out, ‘any work which exposes or is liable to expose any of his employees to asbestos…’ to protect all employees and anyone else who may be affected by the work. There is also a specific duty under CAWR to manage asbestos in buildings to ensure that asbestos is kept in good condition and to prevent uncontrolled work or releases.

1.6 CAWR 2002 is supported by three Approved Codes of Practice that give practical guidance on how to comply with the law. Although failure to observe any of the provisions of an ACOP is not in itself an offence, that failure may be taken by a court in criminal proceedings as proof that a person has contravened the Regulations to which the provision relates. The onus would then be on that person to show that they have complied with the Regulations in an equally effective way. The three ACOPs are described in paragraphs 1.7-1.9.

1.7 Work with asbestos which does not normally require a licence, applies to work on, or which disturbs, building materials containing asbestos; asbestos sampling; laboratory analysis and to the limited, permitted remaining work with asbestos during manufacturing.

1.8 Work with asbestos insulation, asbestos coating and asbestos insulating board applies to work defined in the Asbestos (Licensing) Regulations 1983 (ASLIC), for which a licence is required from the Health and Safety Executive (HSE). It also applies to employers carrying out similar work with asbestos insulation, asbestos coating and asbestos insulating board using their own employees on their own premises, who are exempted from the requirement to hold a licence under regulation 3(2) of ASLIC.

1.9 The management of asbestos in non-domestic premises provides advice on the duties under regulation 4 of CAWR10 to manage the risk from asbestos in non-domestic premises. It explains the duties of building owners, tenants, and any other parties who have any legal responsibility for the premises. It also sets out what is required of people who have a duty to co-operate with the main duty holder to enable them to comply with the regulation.

1.10 Employers must consult safety representatives appointed by recognised trade unions under the Safety Representatives and Safety Committees Regulations 1977 with regard to health and safety issues. Employees not covered by such representatives must be consulted, either directly or indirectly, via elected representatives of employee safety, according to the Health and Safety (Consultation with Employees) Regulations 1996.

1.11 Reference to legislation is made at appropriate points throughout this guidance.

Health effects
1.12 Asbestos-related diseases are currently responsible for more than 4000 deaths a year in the UK and the number is still increasing. Asbestos kills more people than any other single work-related illness. The diseases can take from
15-60 years to develop - so the person who has breathed in the fibres will not be immediately aware of any change in their health. There is an increased risk of ill health associated with exposure to amphibole asbestos fibres (eg amosite, crocidolite) in comparison with chrysotile (Hodgson and Darnton, 2000).

1.13 Asbestos can cause two main types of disease in humans: cancer, particularly mesothelioma and lung cancer; and asbestosis (scarring of lung tissue). Other lung changes such as pleural plaques and diffuse pleural thickening, which are much less disabling, may be indicative of asbestos exposures, but can be due to other causes. New cases of asbestosis are now rare in the UK.

What is mesothelioma?
1.14 Mesothelioma is a cancer of the cells that make up the lining around the outside of the lungs and inside the ribs (pleura), or around the abdominal organs (peritoneum). By the time it is diagnosed, it is almost always fatal. Like other asbestos-related diseases, mesothelioma has a long latency period from first exposure to the onset of disease, on average 30-40 years.

What is lung cancer?
1.15 Lung cancer is a malignant tumour of the lungs’ air passages. The tumour grows through surrounding tissue, invading and often obstructing air passages. The time between exposure to asbestos and the occurrence of lung cancer is on average 20-30 years. It should be noted that there is a synergistic effect between smoking and asbestos exposure which significantly increases the risk of developing lung cancer.

What is the risk to analysts?
1.16 All entry into enclosures carries a risk of exposure to airborne fibres. Analysts entering enclosures while removal or remediation work is being carried out will be potentially exposed to asbestos fibre concentrations above the control limits. Enclosure entry for other reasons such as bulk sampling or clearance inspections and air sampling will encounter lower airborne levels. However, any direct disturbance of asbestos during these situations (eg brushing) can potentially give rise to short-term high exposure. It is important to be aware that as personal exposure is normally underestimated by static monitoring including clearance sampling, such results will not necessarily reflect personal exposure. Therefore regular personal monitoring should be carried out to assess individual risks and confirm the adequacy of respiratory protection. It is recommended that personal monitoring is performed in 10% of jobs involving enclosure entry.

Health surveillance
1.17 Under regulation 21 of CAWR 2002, medical surveillance and health records are required for an employee if the exposure of that employee is likely to exceed the action level (see paragraphs 5.24 to 5.27). The employer should assess the risks of exposure of his employees to determine the requirement for medical examination.

1.18 Analysts should not normally enter live enclosures. However there will be occasions when entry is necessary or required (eg for supervision or checking when there are no or insufficient viewing panels). The results of personal airborne monitoring (see paragraph 1.16) should be used to assist in the risk assessment.

1.19 If an employer decides on the basis of his risk assessment that medical examinations are required, further information can be found in the ACOP Work with asbestos insulation, asbestos coating and asbestos insulating board and Asbestos: The licensed contractors’ guide.

The role of the analyst in asbestos work
1.20 The analyst may be involved in asbestos work in a number of different ways. Most analysts carry out sampling and analysis of bulk and air samples. Some laboratories holding supervisory licences will employ analysts in a supervisory role in asbestos removal (see Chapter 7). More generally however, the analyst’s role has been developing and growing in importance over the years. Most recently CAWR 2002 increased the involvement of the analyst in site clearance procedures. The analyst now has greater responsibility and opportunities for professional judgement. The analyst is responsible for completing site clearance certification for the work area, and for issuing a certificate of reoccupation. In addition, some clients may request greater participation in the asbestos removal work, including pre-clearance inspections and surveys, and site management and monitoring, eg overseeing the smoke test and carrying out some reassurance air sampling during the course of the contract.

1.21 Although not a legal requirement, it is desirable that the analyst is employed by the building owner or occupier for site clearance certification. This arrangement avoids any conflict of interest (perceived or real) that may arise should the analyst be employed by the removal contractor. It also enables an independent party to be involved in resolving any problems that arise during the clearance process. In addition, it has a practical advantage in that all results and certificates of reoccupation can also be issued directly to the person who has responsibility for the premises as well as to the contractor.

Asbestos identification by PLM


Observation mode
(a) Morphology
All modes
(b) Colour and pleochroism(if present)
Polariser only
(c) Birefringence(anisotropic behaviour)
Crossed polars
(d) Extinction characteristics
Crossed polars
(e) Sign of elongation
Crossed polars with first order red compensator
(f) RI assessment
Normally using a dispersion staining, or phase contrast, objective with polariser only

Asbestos identification by PLM
A2.24 Identification of a single asbestos fibre requires the assessment of the following properties in the stated observation modes.
Property Observation mode
(a) Morphology All modes
(b) Colour and pleochroism Polariser only
(if present)
(c) Birefringence Crossed polars
(anisotropic behaviour)
(d) Extinction characteristics Crossed polars
(e) Sign of elongation Crossed polars with first order red compensator
(f) RI assessment Normally using a dispersion staining, or phase contrast, objective with polariser only

Figure A2.2 HSE asbestos reference samples viewed by polarised light microscopy

Figure A2.2 HSE asbestos reference samples viewed by polarised light microscopy (cont)
For a compensator with the slow direction in the NE-SW orientation and polariser aligned in the E-W direction. All phase contrast dispersion mounts used the Series B (1.556, 1.680, 1.692, 1.640, 1.604, 1.604) RI liquids, and McCrones central stop dispersion staining mounts used the Series E high dispersion RI liquids (as given). Approximate magnification is X 100.
Note: crossed polars and crossed polars with a first order compensator plate appearances for anthophyllite, tremolite and actinolite are the same as for amosite.

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