Contents
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
Appendices
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
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;
■enclosures;
■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.
Legislation
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.
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(a) |
Morphology 形状 |
All modes 単ニコル下および直交ニコル下 |
(b) |
Colour and pleochroism(if present) 色と多色性 |
Polariser only 単ニコル下 |
(c) |
Birefringence(anisotropic behaviour) 複屈折 |
Crossed polars 直交ニコル下 |
(d) |
Extinction characteristics 消光 |
Crossed polars 直交ニコル下 |
(e) |
Sign of elongation 伸長の正負 |
Crossed polars with first order red compensator 直交ニコル下で鋭敏色検板使用 |
(f) |
RI assessment 屈折率 |
Normally using a dispersion staining, or phase contrast, objective
with polariser only 通常は、分散染色法あるいは、単ニコル下での位相差法 |
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. HSE(英国健康安全局)(2005)による『Asbestos: The analysts' guide for sampling, analysis and clearance procedures』から 鋭敏色検板が挿入され〔速度の低い(屈折率の高い)方向はNE-SW(北東−南西)方向〕、ポラライザの振動方向はE-W(東西)方向である。それぞれの屈折率をもつ浸液が使われている。倍率は約100倍。 |