During work with asbestos it is often necessary to carry out air monitoring to assess the concentration of airborne asbestos fibre levels that have been generated during the removal / remediation process. Air monitoring is when a measured volume of air is drawn through a membrane filter, which is subsequently mounted on a microscope slide and rendered transparent. Fibres on a measured area of filter are counted using Phase Contrast Microscopy (PCM), and the concentration of fibres in the air is calculated. PCM is carried out in accordance with the Safety Health and Welfare at Work (Exposure to Asbestos) Regulations 2006

Air monitoring may be carried out for the following reasons:

• To confirm that an appropriate level of personal protection has been chosen. This can be achieved by undertaking personal sampling on the employees whilst work is being carried out
• To check the effectiveness of dust suppression methods. This type of monitoring may also be appropriate to monitor the consistency and work practices of individual work teams, or when there is a change in the working method which may require reassessment
• To provide data for employee exposure records. This monitoring should be carried out by taking personal samples within the respiratory zone
• To check that an area is suitable for re-occupation upon completion of asbestos related work. There are potentially many reasons for carrying out air tests, but by far the most common is to check the airborne asbestos fibre levels associated with asbestos removal works

Our air monitoring services include:

1. Background Sampling

Background air monitoring is carried out to establish the respirable fibre concentrations prior to any activity which may lead to airborne asbestos contamination, to ensure that the risk is not being increased as a result of the activity. If fibre levels are found to be elevated prior to asbestos works, consideration should be given to pre cleaning or extending the scope of works. If the contamination is not deemed to be asbestos, this should be taken into consideration when assessing future air monitoring results, such as leak tests. This type of test can also be carried out to check for airborne fibres in situations where it is suspected that asbestos fibres may have been released e.g. by accidental damage or inadvertent disturbance of asbestos materials.

2. Leak Sampling (enclosure check)

This is performed outside the enclosure whilst asbestos work is in progress to check that the environmental control systems are adequate. It is also used to verify that the works are properly contained and that asbestos fibres are not being released into adjacent areas. This is of paramount importance if the adjacent areas are occupied during the works.

3. Personal Sampling

Personal sampling is normally carried out for two main reasons. Firstly as an essential check to ensure that the protection factor afforded by the reparatory protective equipment selected is adequate for the asbestos fibre levels to which workers will be exposed. Secondly, this type of sampling is normally conducted for compliance sampling. This is sampling carried out to assess the personal exposure of workers, and to show that exposure is the lowest level that is reasonably practicable.

4. Clearance Indicator Sampling (clearance testing)

This forms part three of the 4 stage clearance test and requires air monitoring in a cleaned and visually examined enclosure on completion of asbestos removal work. This type of test is conducted in conjunction with an air disturbance using a brush or broom. This is to check that the airborne fibre levels in the asbestos work area are below the clearance level indicator (the limit of quantification 0.01 f/cm3) prior to removal of the asbestos work enclosure and reoccupation of the area.

5. Reassurance Sampling

This type of monitoring is undertaken following work on or near asbestos to confirm that the airborne asbestos fibre levels are less than the occupational exposure limit of 0.1f/cm3.