During a gas leak survey, what must be checked?

During a gas leak survey, the primary focus is to identify the presence of gas leaks. This involves systematically checking potential leak points throughout the gas piping system, such as joints, connections, and valves, where gas could escape. Detecting gas leaks is crucial for ensuring safety, preventing hazardous situations, and maintaining system integrity.

While other factors, like operating pressure levels, corrosion on metal surfaces, and environmental impact, are also important considerations in gas piping systems, they are generally assessed in other types of inspections or evaluations rather than being the central objective of a gas leak survey. The emphasis is specifically on identifying any leaks, as they pose immediate hazards, including fire or explosion risks. Therefore, the focus on the presence of gas leaks makes it the correct answer in this context.