Substandard conditions at the meter header may include a meter without which of the following?

Having a shut-off valve at the meter header is crucial for both safety and maintenance purposes. Shut-off valves allow for quick and easy access to stop the flow of gas during emergency situations or for routine maintenance. This is essential to prevent gas leaks and ensure safety in case of repairs or servicing. Without a shut-off valve, it becomes challenging to isolate sections of the gas piping system, which increases the risk of safety hazards due to uncontrolled gas flow.

Pressure monitors, flow restrictors, and gas leak detectors, while important components for certain applications, do not fulfill the same critical role as shut-off valves in terms of immediate safety and emergency response. Therefore, the absence of a shut-off valve constitutes a substandard condition at the meter header.