Guidance

Annex 2 (regulation 9) measurement of asbestos fibres in the air

Updated 16 May 2023

This guidance was withdrawn on

MGN 669 (M+F) Health and safety asbestos regulations Amendment 1 has been replaced with MGN 669 (M+F) Amendment 2 (Asbestos) regulations 2010.

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Annex 2 - (regulation 9) measurement of asbestos fibres in the air

  1. Depending on the results of the initial risk assessment, and in order to ensure compliance with the limit value laid down in regulation 2, measurement of asbestos fibres in the air at the workplace shall be carried out regularly by a competent person.

  2. Sampling must be representative of the personal exposure of the worker to dust arising from asbestos or materials containing asbestos.

  3. Sampling shall be carried out after consultation of the workers and/or their representatives in undertakings.

  4. Sampling shall be carried out by suitably qualified personnel. The samples taken shall be subsequently analysed, in accordance with paragraph 6, in laboratories equipped for fibre counting.

  5. The duration of sampling must be such that representative exposure can be established for an four-hour reference period by means of measurements or time-weighted calculations.

  6. Fibre counting shall be carried out wherever possible by PCM (phase-contrast microscope) in accordance with the 1997 WHO (World Health Organization) recommended method[footnote 1] or any other method giving equivalent results.

For the purpose of measuring asbestos in the air, as referred to in the first subparagraph, only fibres with a length of more than five micrometres, a breadth of less than three micrometres and a length/breadth ratio greater than 3:1 shall be taken into consideration.

  1. Determination of airborne fibre concentrations. A recommended method, by phase-contrast optical microscopy (membrane filter method), WHO, Geneva 1997 (1SBN 92 4 154496 1) ↩

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