Which of the following is true regarding the flow of gas in a piping system?

In a piping system, the behavior of gas flow is influenced by various factors, particularly usage and demand. Gas pressure is not static; it can fluctuate due to changes in consumption levels. For instance, during peak demand times, the pressure in the gas supply system may drop, affecting the flow rate and efficiency of the system. A well-designed gas system accommodates these fluctuations by maintaining an adequate pressure to ensure consistent delivery, but the reality is that gas pressure often varies with how much gas is being used at any given moment.

The other options do not accurately capture the dynamics of gas flow. Gas does not flow at a constant pressure; it can change in response to system demands. While gas flow can be measured, it is typically not done using standard water meters since they are calibrated for water and not suitable for gas. Lastly, gas does not necessarily always flow downwards; it flows according to pressure differentials and the configuration of the piping system, making vertical rise or fall less of a definitive factor compared to pressure dynamics.