What are the key dust WELs for construction?

Respirable crystalline silica (RCS): 0.1 mg/m3. Hardwood dust: 3 mg/m3 (carcinogen). Cement dust: 1 mg/m3. General inhalable dust: 10 mg/m3. General respirable dust: 4 mg/m3. These are 8-hour time-weighted averages.

Why is silica dust so dangerous?

Silica dust (from cutting concrete, stone, brick, mortar) causes silicosis - irreversible scarring of the lungs. It is also classified as a carcinogen (lung cancer). The WEL is very low (0.1 mg/m3) because even small amounts over time cause permanent damage. Use water suppression and on-tool extraction.

What is the difference between inhalable and respirable dust?

Inhalable dust is the larger fraction that enters the nose and mouth (WEL 10 mg/m3). Respirable dust is the finer fraction that penetrates deep into the lungs (WEL 4 mg/m3). Silica and wood dust limits are for the respirable fraction as this causes the most harm.

Is on-tool extraction effective?

On-tool dust extraction (vacuum attached to the tool) can reduce airborne dust by 80-95% when properly maintained. It is the most effective control after elimination and is required by HSE for silica-generating tasks. Always use an M-class or H-class vacuum extractor.

When must I use RPE for dust?

RPE must be used when engineering controls (extraction, water suppression) alone cannot reduce exposure below the WEL. For silica dust tasks, RPE is almost always needed alongside extraction. FFP3 is the minimum for silica. All tight-fitting RPE must be face-fit tested.

TradeCalculator

Dust Exposure Calculator

Check construction dust levels against WELs and select appropriate RPE

Dust Type

Estimated Dust Level

Exposure Duration

RPE Selection

How We Calculate This

Select the dust type to look up its WEL. Enter the estimated airborne concentration and exposure duration. The calculator computes the 8-hour TWA, applies dust extraction efficiency if used, then divides by the RPE Assigned Protection Factor to give the protected exposure level. This is compared against the WEL to determine compliance and the minimum RPE grade required.

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.