Safe Environments carry out asbestos air monitoring in accordance with the document entitled Guidance Note on the Membrane Filter Method for Estimating Airborne Asbestos Fibres 2nd Edition [NOHSC: 3003 (2005)].
The National Occupational Health and Safety Commission recommend that asbestos air monitoring should be performed whenever ACM are being removed, to ensure that control measures are effective when working on or removing asbestos containing materials. Airborne asbestos fibres are generated by the disintegration of asbestos containing materials.
Asbestos air monitoring samples the respirable asbestos fibres in the air to assist in assessing exposure and the effectiveness of control measures. This is generally undertaken where asbestos containing products are in a poor condition, potentially liberating asbestos fibres into the air, or where asbestos containing materials are being removed.
For the purposes of asbestos air monitoring, only respirable asbestos fibres (those fibres less than 3μm wide, more than 5μm long and with a length to width ratio of more than 3 to 1) are considered to be a risk. Asbestos air monitoring includes exposure monitoring, control monitoring and clearance monitoring.
Exposure monitoring samples the air in a person’s breathing zone to determine a person’s likely exposure to respirable asbestos fibres. Exposure monitoring is designed to estimate the person’s exposure, so that it may be compared with the national exposure standard.
Control monitoring samples the air to measure the level of respirable airborne asbestos fibres in an area during work on asbestos containing materials. Control monitoring is designed to assist in assessing the effectiveness of control measures while work or removals is undertaken on asbestos containing materials.
Clearance monitoring samples the air to measure the level of airborne asbestos fibres in an area following work or removal of asbestos containing materials. An area is ‘cleared’ when the level of airborne asbestos fibres is measured as being below 0.01 fibres/mL.