What should be used to monitor potential hazards during overhaul operations?

The use of a multi-gas meter during overhaul operations is critical for monitoring potential hazards because it can detect the presence of various dangerous gases that may pose risks to firefighters. During overhaul, it is common for firefighters to be in areas that were previously involved in a fire, where various combustible materials might have created toxic environments. The multi-gas meter can identify harmful gases such as carbon monoxide, hydrogen cyanide, and explosive levels of gases, which are essential for the safety of personnel working in those areas.

While other tools like thermal imagers and smoke detectors are useful in specific scenarios—such as identifying hotspots or detecting smoke respectively—they do not provide the comprehensive analysis of gas levels that a multi-gas meter does. A water pressure gauge, on the other hand, is not relevant for monitoring hazardous atmospheric conditions. Thus, for ensuring safety during the overhaul phase, the multi-gas meter stands out as the most appropriate choice to adequately assess potentially harmful environments.