Minimum airflow is about the filter and its penetration variables, not a cloth mask. The guide relates to supposed airflow in p1-p3 filters.
If you are working in a regulated environment wherein you need to control your exposure to airborne fibre particles (stripping asbestos, drilling into silica based materials, welding etc etc) as a result of the work your filter- whether its powered rpe or a sundstrom half-mask- will need to be regularly serviced and/or replaced due to accumulation of fibres/dust/crystallised silica/contamination etc.
Equally you'd need to undergo a face-fit test to ensure your mask was the correct fit, you are able to breathe correctly during physical duress. Intermittent personal monitoring dependent on regulatory task- the type of filter will dictate the work you're doing.
The fact that this argument hinges on "restricted airflow" (this isn't what it means at all) rather than the statement that the BSI is condoning work with insufficient filter penetration just displays the lack of knowledge on the subject all round. It's shocking that the literature says that but no-one has picked up on it here tbh. If someone turned up to work up in a licensed enclosure in a paper p3 without a face fit you'd send them home. Admissions like that show how much of a mess we're in.
Anyway- the same would apply with a disposable mask with a valved internal filter, which is what the guide relates to. You undertake a random paraffin test on a percentage of the batch to ensure the filter is what it says it is- when you see news articles talking about insufficient PPE, that's the concept. It's like lashing an overused pre-filter in your half mask or using one that's been through a few enclosures- you are instantly aware it's been used as your airflow is restricted.
You used to be able to buy a valved p3 in wilkos if you'd like to test out the variables- it's likely they're rare as fuck now- or maybe somewhere like arcos if you're Essex way. If you'd like to try the face filter test yourself - i.e. undertake a fit for work medical--safetys are still doing them in the pandemic though I think they're quite expensive due to vastly expanded risk assessments.
I understand the narrative of the thread although perhaps not the motivations, but it's rare for me to have slight knowledge about a subject on here that isnt marginal London rappers- apologies for the length of the post.
I would, however assume if someone genuinely had difficulty breathing through a cloth mask there are much bigger issues at play. No p3 mask is going to save you then, you are fucked and should be shielding.
