These are general Friday musings, please take this into account.
Into the bear pit again.
What the panel may be implying is that if you have identified non-friable intact cement bonded ACM fragments in shallow soils in residential lawned and plant borders (not an uncommon occurrence on urban land), that a few incidents (detection in 13% of samples analysed (~1 in 8) in this case study), of measurable levels % w/w (max ~0.5% w/w in this case study) in a data set is likely to mean the site is within Cat 4.
To me, on a precautionary basis, the study site could be a candidate for the dodge-the-issue fence-sitting Part 2A Category 3 (Human Health) wrt to asbestos: i.e. not quite sure was the risk level is, but definitely not Cat 2.
As it's Friday, anyone care to take a stab at an implied C4SL %w/w for intact cement bonded ACM fragments ..... (the straight average w/w across the 15 samples analysed from the case study is 0.036% w/w).
Interestingly, if I use the JWIG Work Categories DST and this average %w/w (which is a 'Low Quantity' in the DST) and apply to a soil sampling investigation at a site with similar conditions, then it would be probable NLW. The need for RPE/dust-suppression/hygiene during the soil sampling works revolves around the DST Stage 2 Choices, including anticipated airborne fibre concentration, host matrix and respirable fibre index.
Chris Dainton
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