Where should the gas piping systems not be interconnected when two or more meters are used?

Gas piping systems should not be interconnected on the outlet side of the meters to ensure accurate measurement and regulation of gas flow. Each meter is designed to measure the gas usage for its specific service. If piping systems are interlinked on the outlet side, it can lead to discrepancies in the measurement of gas consumption, potentially resulting in billing issues and safety hazards.

By maintaining separate lines after the meters, each system operates independently, allowing for precise tracking of gas flow for each meter. This arrangement ensures compliance with safety regulations, avoids backflow issues, and supports the integrity of the metering process.

Interconnecting before the meter connections or on the inlet side can sometimes be permissible under specific conditions, as it may not interfere with the measurement of gas flow. However, interconnecting after the meters compromises the accuracy and accountability that meters are meant to provide.