I wouldn't normally use a "wot we do" story but my recent stint in a manufacturing company involved a lot of dust scenarios. So the following is a summary of basic experiments and some professional monitoring. Bit rambling I’m afraid.
Not sure if this work is outside or inside and how large etc. HSE COSHH guide CN5 may help.
Vacuums are always recommended – but if the premises are large and open, this is hopeless for expansive floor areas, although good for corners, edges, around machinery and to collect small piles. However, if you can use a vac, fine. Then no RPE need probably.
Use a powerful torch (dust lamp), to see where dust is, and how it is moving. It will help to test out some methods described, and will also indicate (but not measure) the amounts in the air.
Rather than brushing, think pushing.
It is the ‘flicking’ of the material with the brush which pushes dust into the air more than anything. Experiment with a cloth wrapped around the brush head (yard broom for example).
Then use dust lamp to see how much (if any) dust gets airborne compared with dry brushing.
Pushing such a covered yard brush around a large floor space is quicker, quieter and easier; the collected piles can then be vacuumed. A commercial dust broom (as used in hospital corridors) may be an alternative with larger sizes of ‘sweeper’ head.
Another alternative might be a push (non-powered) wheeled floor sweeper, (google for examples) although emptying these brings its own problems, resolved with technique.
In the olden days, and still in the States, ‘sweeping compound’ could be used, although for very large areas this is not so practical. This compound is basically a recipe based on damp sawdust. It can make certain floors slippery though.
For our experiments, the environmental specialist measured dust levels at lapel height whilst the following tasks were carried out: dry sweeping (poor), dry pushing with cloth-covered broom (good), dry pushing with dust ‘mop’ about 16” wide, (good and speedy), and mechanical hand push sweeper (also good, but the emptying was not measured, and that is where dust can get into breathing zones).
If RPE is still called for (and it may not be), FFP3 disposable should be fine, and comfortable enough for long periods; foldable so as not to be left on top of benches to get dust and muck inside. Others have covered the detail of dust as a hazard. A simple set of instructions talked through should be sufficient, covering the dust controls and anything else such as keeping safe from moving vehicles or machinery etc all in one.
Private ramble: I had my own dust challenges when using very lightweight insulating plaster (think talcum powder). No matter how much I swept, the unfinished sub floor seemed to release more dust each sweep. Plaster dust ruins domestic vacs, and again, even the 50sqm floor was a lot to vacuum anyway – took ages.
Solution? Dampened sawdust: scattered liberally across the chipboard floor and then swept up into buckets to be reused. Managed to capture and contain most dust very effectively. If left down on the floor whilst working, this mixture also seemed to draw airborne dust straight down into it too. Not scientifically validated.
This is not a practical suggestion for a workplace these days, but it was used in cotton mills back in the day for dust control. And may be a handy tip for anyone having building work done.