What should be checked before working in a manhole?

Before working in a manhole, it is critical to check for gasses and oxygen deficiency to ensure a safe working environment. Manholes can contain hazardous gases, such as methane or hydrogen sulfide, which can pose serious health risks, including asphyxiation or poisoning. Additionally, a lack of sufficient oxygen can lead to impaired physical and mental function, which can endanger the lives of workers. Monitoring these factors is an essential part of ensuring safety protocols are followed, as it prevents dangerous exposure and helps maintain a breathable atmosphere in enclosed spaces.

While temperature and humidity are important for general working conditions, they do not directly pose the immediate hazards that gasses and oxygen levels do. Electrical current, while a key concern in the vicinity of manholes, does not address the specific risks associated with working in a confined and potentially hazardous space. A visual inspection of the manhole is also necessary, but it primarily checks for structural integrity or visible hazards rather than the critical environmental conditions that gasses and oxygen levels represent. Therefore, ensuring the absence of harmful gasses and adequate oxygen supply is paramount before commencing work in a manhole.