‘Airborne asbestos’ means any fibres of asbestos small enough to be made airborne.

For the purposes of monitoring airborne asbestos fibres, only ʻrespirable fibresʼ
are counted;
‘Asbestos’ means the following fibrous silicates:
(a) asbestos actinolite,
CAS No 77536-66-4(*);
(b) asbestos grunerite (amosite),
CAS No 12172-73-5(*);
(c) asbestos anthophyllite,
CAS No 77536-67-5(*);
(d) chrysotile, CAS No 12001-29-5(*);
(e) crocidolite, CAS No I2001-28-4(*); and
(f) asbestos tremolite,
CAS No 77 536-68-6(*),
*references to ‘CAS’ followed by a numerical sequence are references
to CAS Registry Numbers assigned to chemicals by the
Chemical Abstracts Service, a division of the American Chemical
Society;
‘Asbestos abatement’means a number of procedures that are available to control fibrerelease from ‘ACMs’ in a building, including

• removal,
• encapsulation,
• repair,
• enclosure,encasement, and operations and maintenance programs such as environmental cleaning;

‘Asbestos-containing material (ACM)’ means any material or article that, as part of its design, contains asbestos;

‘Asbestos-contaminated dust or debris (ACD)‘
means dust or debris that has settled within a workplace and is (or is assumed to be)
contaminated with asbestos;

‘Asbestos Regulations’ mean the Safety, Health and Welfare at Work (Exposure to Asbestos) Regulations,

‘Authority’ means the Health and Safety Authority;

‘Competent person’ 
For the purposes of the relevant statutory provisions, a person is deemed to be a competent person where, having regard to the task he or she is required to perform and taking account of the size or hazards (or both of them) of the undertaking or establishment in which he or she undertakes work, the person possesses sufficient training, experience and knowledge appropriate to the nature of the work to be undertaken.

‘Exposure limit value’ for asbestos is a respirable fibre level of 0.1 fibres per cubic
centimetre of air measured in a person’s breathing zone and expressed as a time-weighted average fibre concentration calculated over an eight-hour working day;

‘Friable asbestos’ means that an ACM is less resistant to mild abrasion or damage and is
more likely to release inhalable fibres;

‘HEPA’ means High Efficiency Particulate Arrestor with a collection efficiency of 99.95% for the most penetrating particle size. Filters with higher efficiency may be used;

‘Non-friable asbestos’ means material containing asbestos that is resistant to mild abrasion and damage and less likely to release inhalable fibres;

‘Respirable fibre’ means an asbestos fibre that is:
(a) less than 3 microns (μm) wide,
(b) more than 5 microns (μm) long, and
(c) has a length to width ratio of more than 3:1;

‘TWA’ means time-weighted average;
‘WHO reference method’ means Determination of airborne fibre number concentrations: A recommended method, by phase-contrast optical microscopy (membrane filter method). WorldHealth Organisation, 1997;
‘0.1 f/cm3’ means 0.1 fibres per cubic centimetre of air as an eight-hour time-weighted average.
f/cm3 can also be expressed as fibres per millilitre of air or f/ml.