Air Monitoring
Air monitoring involves drawing a known flow rate of air through a filter for a measured time, so that airborne particles are collected. The filter is prepared for examination under a microscope and then a known fraction of the filter is analysed with all fibres of a certain type being counted. The number of fibres is compared against the sample's volume of air, and the fibre concentration is calculated.
The method of filter analysis normally carried out by G & L Consultancy Ltd is Phase Contrast Microscopy (PCM), which is suitable in almost every circumstance. On very rare occasions other methods such as Scanning Electron Microscopy (SEM) or Transmission Electron Microscopy (TEM) might be required, which will only be done following consultation with the client.
The different types of Air Monitoring available are as follows:
Background Monitoring
Static monitoring, to collect 480 litres of air, before any asbestos removal work has been carried out to find out what the ambient asbestos fibre level is in an area.
Background Monitoring is very useful to establish whether a problem exists before any removal work begins, especially in relation to any future Leak Monitoring and any problems that might occur with the Clearance Monitoring.
Leak Monitoring
Static monitoring, to collect 480 litres of air, around the area of the asbestos removal work, during the removal process.
Leak Monitoring can help ensure that the Control Measures used during the removal work are adequate. A high result from Leak Monitoring will give you early warning that asbestos fibres are spreading away from the area of the asbestos removal works. A high leak test result is particularly significant if previous Background Monitoring has demonstrated that the area had no ambient fibre level before the asbestos removal work began.
Reassurance Monitoring
Static Monitoring, to collect 480 litres of air, after minor asbestos work, following an emergency or following an uncontrolled release.
Reassurance Monitoring is run to give reassurance that the air is free from
asbestos fibres following certain events:
- If non-licensable asbestos has been removed, Reassurance Monitoring is run
to ensure no asbestos fibres remain in the former work area.
- Following a breach in an asbestos enclosure and the subsequent clean up,
Reassurance Air Monitoring is required to demonstrate that the area is safe
to re-enter.
- Following the discovery of damaged asbestos in an area and the subsequent
remedial actions, Reassurance Monitoring is required to demonstrate that the
remedial actions are sufficient until the damage can be fully dealt with by
licensed contractors.
4-Stage Clearance Monitoring for Certificate of Reoccupation
Static Monitoring, to collect 480 litres of air, following controlled asbestos removal work; with the number of samples required being dependent on the size of the area.
Clearance Monitoring must be conducted by a UKAS accredited analytical Company
following licensable removal work. The Clearance Monitoring involves four
distinct stages:
Stage 1: Preliminary check of site condition and job completeness;
Stage 2: A thorough visual inspection inside the enclosure/work area;
Stage 3: Air Monitoring;
Stage 4: Final assessment post-enclosure/work area dismantling
Only after successful Clearance Monitoring can an area be classed as safe to re-enter.
Personal Monitoring
Mobile (personal) Monitoring, to collect between 40 and 240 litres of air for comparison against established Control Limits and Action Levels.
Personal Monitoring is conducted on the person, with a small sampling pump being placed on the belt of the wearer and the air being sampled as close to the wearer's mouth as possible.
Personal Monitoring is used to ensure that the person wearing the sampling pump is adequately protected from whatever levels of airborne asbestos fibres are present.
