Dust, Silica and Small Workshops: A Sensible Extraction Plan for UK Masons

Silica dust gets sold like a gadget problem. Buy this extractor, add that air scrubber, subscribe to a monitoring app, and somehow the workshop is safe. The reality in a small UK masonry shop is duller and cheaper: you need a few controls working together, written down, and actually used every day. Here is a plan that will stand up to a sensible HSE visit without turning the place into a catalogue showroom.

Start with the hazard, not the hardware

Respirable crystalline silica, usually shortened to RCS, is the fine fraction of stone dust that gets deep into the lungs. It is not the visible cloud you cough up after a dry cut. It is the stuff you cannot see, and it is why silicosis still turns up in stonemasons who thought they were careful.

Under COSHH, you need a suitable and sufficient risk assessment for the work that creates the dust. The workplace exposure limit for RCS is 0.1 mg/m³ as an 8-hour time-weighted average, but good practice is to get well below that, not sit on the line. You cannot buy compliance off the shelf. You control exposure with the right hierarchy: stop making dust where you can, contain it where you cannot, and use RPE as the last layer, not the first.

The four controls that do the real work

1. On-tool extraction

For most small workshops, a decent M-class dust extractor is the minimum starting point for stone dust. If you are cutting or grinding high-silica material regularly, or the work is confined, look at H-class. The extractor is only half the job. The shroud has to fit the grinder or cutter properly, the hose has to be the right diameter and length, and the filter has to be clean enough to pull air. A domestic vacuum with a fancy sticker is not an extraction system.

Check airflow before you start, not after the workshop has disappeared under a grey haze. Empty the bag or bin before it is full. Check hoses for splits. On-tool extraction counts as local exhaust ventilation, so it needs user checks and a thorough examination and test by a competent person, normally at least every 14 months. Write it down. A clipboard in the office is cheaper than a bad inspection.

2. Water suppression

Wet cutting is one of the most effective things a small stone shop can do. It knocks down dust at source and keeps the blade cooler. The catch is slurry. Wet slurry that dries out becomes fine dust again, so you need a plan for bunded cutting areas, trays, hoses and cleaning. Do not let slurry dry on the floor and then sweep it up. That is just a dust factory with extra steps.

For hand work, a small water feed or suppression bottle can make a real difference. For bench work, a proper wet station with a settling tray and a clear cleaning routine is worth more than a wall of expensive filters.

3. RPE

FFP3 disposable masks are the usual minimum for stone dust, and they need to fit. That means face-fit testing, clean-shaven skin where the seal sits, and a proper check every time you put one on. Store masks clean and dry, replace them when they are clogged or damaged, and do not let anyone wear a beard under the seal and call it close enough.

RPE is uncomfortable, which is exactly why it gets skipped. Make it easy: keep the right masks in the right place, train people on the fit check, and lead from the front. If the boss cuts dry with his mask hanging off, the message is clear.

4. Housekeeping

Dry sweeping and compressed air are the two fastest ways to put settled silica back into the air. Use a vacuum with the right filtration, or wet methods. Clean benches and ledges regularly. Bag waste properly. Keep the floor clear so people are not kicking dust around. It sounds basic because it is basic, but it is where a lot of small workshops come unstuck.

LEV checks and the paperwork an inspector expects

An HSE inspector is not usually looking for perfection. They are looking for evidence that you have identified the risk and put sensible controls in place. That means a COSHH risk assessment that actually describes your stone work, not a generic template with the name changed.

Keep a simple LEV log. Record weekly user checks, filter changes, repairs, and the thorough examination and test. Keep RPE fit-test records and training records. Have a maintenance schedule for extractors and water systems. If you use health surveillance, keep those records too. Review the assessment when the work changes, not once every five years when someone remembers.

A useful test is this: if an inspector asked you to show your silica controls, could you put a folder on the table in two minutes? If not, fix that before buying another gadget.

Budget tiers that make sense

Tier	Realistic spend	What it buys	Best for
Essential	£500-£900	M-class extractor, correct shroud and hose, FFP3 fit testing, basic wet-cutting kit, signage, COSHH assessment	Small shops doing occasional cutting and grinding
Serious small shop	£1,500-£3,000	Better extraction, H-class where needed, dedicated wet station, spare filters, training, simple air monitoring	Busier workshops with daily stone dust
Fixed LEV and controls	£5,000+	Fixed extraction, enclosures, commissioning, ongoing examination and test, health surveillance	Production work with high and continuous exposure

You do not need to jump to the top tier on day one. You do need to be honest about what your work creates. A shop cutting a few lintels a week is not the same as a shop running a saw all day.

What to skip, at least for now

Do not buy an air quality monitor before you have fixed the basic extraction and housekeeping. Do not rely on paper dust masks. Do not buy a huge fixed LEV system if wet cutting and on-tool extraction would solve the problem for a fraction of the cost. And do not treat a shiny extractor as a substitute for cleaning the workshop.

The plan is not glamorous: extract at the tool, suppress with water, fit the mask properly, clean wet, check the LEV, and keep the paperwork simple enough that you will actually maintain it. That is what passes muster.