NEBOSH CC Dust & Noise in Construction 1 — Questions and Answers
Question 1: Which disease is caused by the inhalation of respirable crystalline silica (RCS) dust on construction sites?
- Silicosis (Correct answer)
- Asbestosis
- Mesothelioma
- Pneumoconiosis (coal dust)
Correct answer: Silicosis
Silicosis is a fatal, irreversible lung disease caused by breathing in fine respirable crystalline silica (RCS) dust from materials such as concrete, mortar, sandstone and granite. It causes progressive scarring of the lung tissue.
Question 2: Which construction activities commonly generate respirable crystalline silica dust?
- Cutting, grinding, drilling and chasing concrete, brick, stone and mortar (Correct answer)
- Painting and decorating
- Electrical installation
- Plumbing and pipework
Correct answer: Cutting, grinding, drilling and chasing concrete, brick, stone and mortar
Cutting, grinding, drilling and chasing operations on silica-containing materials such as concrete, brick, stone and mortar produce very high concentrations of RCS dust. Dry cutting is particularly hazardous and should be avoided.
Question 3: What is the Workplace Exposure Limit (WEL) for respirable crystalline silica dust under EH40?
- 0.1 mg/m³ (8-hour TWA) (Correct answer)
- 1.0 mg/m³ (8-hour TWA)
- 0.5 mg/m³ (8-hour TWA)
- 0.01 mg/m³ (8-hour TWA)
Correct answer: 0.1 mg/m³ (8-hour TWA)
The WEL for respirable crystalline silica is 0.1 mg/m³ as an 8-hour time-weighted average (TWA). This is a very low concentration, reflecting the significant hazard posed by even small amounts of RCS dust.
Question 4: What is the most effective engineering control for reducing dust during dry cutting operations on a construction site?
- On-tool dust extraction combined with water suppression (wet cutting) (Correct answer)
- Wearing a dust mask only
- Working quickly to minimise exposure duration
- Performing all work outdoors
Correct answer: On-tool dust extraction combined with water suppression (wet cutting)
On-tool dust extraction captures dust at the point of generation before it becomes airborne. Combined with wet cutting (which uses water to suppress dust), this provides the most effective engineering control. RPE should also be worn as a supplementary measure.
Question 5: Which regulations govern occupational exposure to hazardous substances including dust on construction sites?
- Control of Substances Hazardous to Health Regulations 2002 (COSHH) (Correct answer)
- Workplace (Health, Safety and Welfare) Regulations 1992
- Control of Dust at Work Regulations
- Personal Protective Equipment at Work Regulations 1992
Correct answer: Control of Substances Hazardous to Health Regulations 2002 (COSHH)
COSHH 2002 requires employers to assess, prevent or control exposure to substances hazardous to health, including dusts such as RCS, wood dust and asbestos. The regulations require a COSHH assessment for all hazardous substances.
Question 6: What type of respiratory protective equipment (RPE) is required when working with high-hazard dusts such as RCS?
- Minimum FFP3 disposable filtering face piece or powered air purifying respirator (PAPR) (Correct answer)
- FFP1 dust mask only
- A standard surgical mask
- Any face covering that covers the nose and mouth
Correct answer: Minimum FFP3 disposable filtering face piece or powered air purifying respirator (PAPR)
For high-hazard dusts such as RCS, a minimum of FFP3 RPE is required. For sustained or higher-exposure activities, a powered air purifying respirator (PAPR) or supplied air respirator may be needed. FFP1 and FFP2 do not provide sufficient protection.
NEBOSH CC Dust & Noise in Construction 1
Which disease is caused by the inhalation of respirable crystalline silica (RCS) dust on construction sites?