Yunku Industrial Safety

As a typical confined space operation scenario, sewage pipeline combines the risks of toxic gases, oxygen-deficient environment, and complex structure, and its operation safety has attracted much attention.

Sewage pipeline operations face a triple deadly threat:

1. Gas risk: hydrogen sulfide (H₂S), methane (CH₄) and other toxic and hazardous gas concentrations can reach a lethal amount within 5 minutes, the traditional portable detector there is a monitoring blind spot;

2. Physical risk: slippery pipe walls, narrow space leading to personnel trapped rate as high as 34%, conventional rescue equipment is difficult to respond quickly;

3. Biological risk: the proportion of operating environments with excessive aerosol concentrations of pathogenic microorganisms is 61%, and there is an exposure risk for ordinary protective equipment.

In 2021, the investigation of an accident at a city sewage treatment plant showed that the operators failed to sense the hydrogen sulfide accumulated at the bend of the pipeline in time, resulting in the poisoning of three people, exposing the lagging nature of the traditional protection system. Therefore, enterprises should organise safety training for operations in confined space according to regulations, especially focusing on ‘five types of personnel’ such as approvers of operations in confined space, persons in charge of the site, guardians, operators and emergency rescue personnel. It should carry out risk identification, hierarchical control, hidden danger investigation, emergency drills, etc., provide labour protection equipment that meets the requirements, and equip safety facilities and equipments according to the regulations. To strengthen the management of contracting, contracting, can not be ‘contracted out’, do not care. Safety protection should follow the principle of ‘prevention first, prevention and control combined’, and build a whole-process prevention and control system covering the pre-, mid- and post-operations.