This standard outlines the essential safety practices and protocols for tunnelling work, including shaft sinking, excavation, drilling, and blasting. It details critical requirements for ventilation, illumination, fire protection, and the handling of hazardous gases to ensure the occupational health and safety of workers in underground environments.
Safety code for tunnelling work
Quick Reference Values
Minimum oxygen content in tunnel atmosphere19.5% by volume
Maximum permissible concentration of Carbon Monoxide (CO)50 ppm
Maximum permissible concentration of Carbon Dioxide (CO2)0.5% by volume
Maximum permissible concentration of Nitrogen Dioxide (NO2)5 ppm
Maximum permissible concentration of Hydrogen Sulphide (H2S)10 ppm
Practical Notes
Strict adherence to gas monitoring protocols is mandatory to prevent asphyxiation or explosions.
A dedicated mechanical ventilation system must be designed to rapidly clear toxic fumes post-blasting.
Loose rock scaling (barring down) must be rigorously performed by experienced personnel before allowing muck removal crews to enter.