In order to determine the concentration of asbestos fibres in the atmosphere air monitoring and analysis must take place. The membrane filter method is the most commonly used method to acquire a concentration as it is the most accurate, time-efficient and cost-effective.
In order to obtain a concentration a determined amount of air is drawn through a filter and using laboratory techniques mounted onto a microscope slide and examined under a phase contrast microscopy. The results of fibre counting are entered into a calculation which is then able to be compared to the WorkSafe guidelines as detailed in the Workplace
Exposure Standards and biological exposure indices; Asbestos (all forms) confirmed carcinogen 0.1 asbestos fibres per millilitre of air, averaged over an 8-hour period.
Regulation 9(1) of the Health and Safety at Work (Asbestos) Regulations 2016 (the ‘Asbestos Regulations’) requires PCBUs with management or control of a workplace to ensure that exposure of a person at the workplace to airborne asbestos is eliminated so far as is reasonably practicable. If it is not reasonably practicable to eliminate exposure to airborne asbestos, exposure must be minimised so far as is reasonably practicable.
Regulation 9(2) of the Asbestos Regulations requires PCBUs with management or control of a workplace to ensure that the airborne contamination standard for asbestos is not exceeded at the workplace (however, in relation to an asbestos removal area where class A asbestos removal work is being carried out, the regulations impose a more stringent standard). These requirements work together to ensure that there is a limit to the amount of asbestos that is permitted in the air of a workplace, without implying or meaning that the level delineates what is acceptable for personal exposure.
Personal exposure must be eliminated or minimised so far as is reasonably practicable. The WES provided within this guide for asbestos must be applied accordingly.