The Importance of Ventilation and Dust Control
A critical aspect of any tunnel construction is ventilation design and dust control, so that workers exposure to fumes and dust are reduced to safe, acceptable levels.
Silica or silicon dioxide is a naturally occurring and widely abundant mineral that forms a major component of most rocks and soils. Crystalline silica dust is the biggest risk to construction workers after asbestos as dust particles can penetrate deep into the lungs. Heavy and prolonged exposure to RCS can cause lung cancer, silicosis, chronic obstructive pulmonary disease and other serious respiratory diseases. Silicosis usually follows exposure to RCS over many years, but extremely high exposures can cause acute silicosis more quickly.
New health and safety regulations specifically relating to the control of respirable crystalline silica (RCS), have been introduced to bring it into line with asbestos. Many countries are now halving the workplace exposure limit (WEL) for RCS for an 8-hour time weighted average from 0.1mg/m3 to 0.05mg/m3.
Due to the high production volume and enclosed workspace, workers in underground operations have a higher risk of dust exposure. Management of dust within tunnel construction usually requires a hierarchy of control measures to be implemented including the use of dust scrubber (dust collector) and providing ventilation at the face through brattice wings or ducting.