Testing and analysis for asbestos fibres (including asbestiform fibres that fit the respirable criteria) are then carried out. The work enclosure is brushed at the start of the sample run to disturb any unseen fine-settled dust that is likely to contain asbestos fibres. Such dust could give rise to high levels of exposure during the dismantling of the enclosure or subsequent cleaning/maintenance activities in the work area.
Samples are collected on filters which are removed from the enclosure and counted on-site using PCM (Phase Contrast Microscopy). Should the air tests be assessed as suitably clean, stage 3 can be signed or ready for the dismantling of the removal enclosure.