Key points to cover
- Respirable crystalline silica (RCS) is found in concrete, mortar, sandstone, granite, and many other common building materials
- The workplace exposure limit (WEL) for RCS is 0.1 mg/m³ (8-hour TWA) — this is a very small amount
- Silicosis, lung cancer, and COPD are all linked to silica dust exposure
- Water suppression and on-tool extraction are the primary controls — they must be used when cutting, grinding, or drilling these materials
- Never dry sweep or use compressed air to clean up dust — use an H-class vacuum or damp down
- RPE is required in addition to water suppression and extraction where exposure may still exceed the WEL
Do's and don'ts
Do
- Use water suppression on every disc cutter, wall chaser, and floor grinder
- Use on-tool dust extraction connected to an H-class or M-class vacuum
- Wear RPE (minimum FFP3) when cutting, grinding, or drilling stone, concrete, or mortar
- Clean up with an H-class vacuum or damp down — not a broom
- Attend health surveillance (lung function tests) when offered
Don't
- Never dry cut concrete, stone, or mortar
- Never use compressed air to blow dust off yourself or surfaces
- Never dry sweep construction dust — it creates an invisible cloud of fine particles
- Never remove your mask while dust is still in the air — wait until the area is clear
- Never ignore a persistent cough or breathlessness — see occupational health
Questions to check understanding
Q1: What is the workplace exposure limit for respirable crystalline silica?
Show the answer
0.1 mg/m³ as an 8-hour time-weighted average. This is a very low level — a small amount of uncontrolled cutting can exceed it.
Q2: Name two ways to control silica dust when cutting concrete.
Show the answer
1) Water suppression — a continuous water supply to the blade or disc to suppress dust at source. 2) On-tool extraction — a dust collection system attached directly to the tool, connected to an H-class vacuum.
Q3: Why is silicosis so dangerous?
Show the answer
Silicosis is incurable and progressive — even after exposure stops, the disease can continue to worsen. It causes permanent scarring of the lungs, reducing breathing capacity, and significantly increases the risk of lung cancer.
Q4: What type of vacuum should be used to clean up construction dust?
Show the answer
An H-class vacuum (or at minimum M-class for lower-risk dusts). H-class vacuums have HEPA filters that capture 99.995% of fine particles, including respirable silica dust. A standard domestic or industrial vacuum is not suitable.
This is general guidance for UK construction sites. Check it against your own risk assessment, method statement and the site before you deliver it.