Describe air monitoring requirements in underground works.

Air monitoring in underground works is essential to ensure the safety and health of workers and to comply with regulatory requirements. Underground works such as tunnels, mines, and underground construction sites can present various hazards, including poor air quality, hazardous gases, and oxygen-deficient atmospheres. Therefore, regular air monitoring is necessary to detect and mitigate these hazards effectively. The following are key requirements for air monitoring in underground works:

1. Baseline Monitoring: Conduct baseline air monitoring before starting work in underground environments to establish initial air quality conditions. Baseline monitoring provides essential data on the concentrations of gases, dust, and other contaminants present in the underground atmosphere. This information serves as a reference for comparison during subsequent monitoring activities and helps identify changes or deviations that may indicate potential hazards or exposure risks.

2. Continuous Monitoring: Install continuous air monitoring systems or real-time air quality sensors in underground worksites to monitor air quality continuously. These monitoring systems can detect changes in air quality in real-time and provide immediate alerts or alarms if hazardous conditions are detected. Continuous monitoring is particularly important in areas with known hazards such as confined spaces, ventilation ducts, or areas prone to gas accumulation.

3. Periodic Monitoring: Conduct periodic air monitoring at regular intervals or as required by regulations to assess ongoing air quality conditions and ensure compliance with exposure limits and safety standards. Periodic monitoring involves sampling air samples using portable gas detectors, air quality meters, or sampling pumps at various locations throughout the underground worksite. Sampling should be conducted in areas where workers are present or where hazards are likely to occur, such as excavation faces, ventilation systems, and confined spaces.

4. Gas Detection: Use gas detection instruments or multi-gas monitors to detect and measure concentrations of hazardous gases commonly found in underground environments, such as methane, carbon monoxide, hydrogen sulfide, and oxygen. Gas detectors should be calibrated regularly, properly maintained, and worn by workers as required to ensure accurate monitoring and timely detection of gas hazards.

5. Recordkeeping and Documentation: Maintain accurate records of air monitoring results, including measurement data, sampling locations, dates, and times. Documentation should include details of monitoring activities, findings, corrective actions taken, and any incidents or exposure incidents. Records should be retained for a specified period as required by regulations and made available for review by regulatory authorities or safety inspectors.

By implementing these air monitoring requirements, employers can effectively identify and control hazards in underground worksites, protect workers' health and safety, and ensure compliance with regulatory standards. Regular air monitoring helps mitigate risks associated with poor air quality, hazardous gases, and confined spaces, enabling safe and productive operations in underground environments.