In gas equations, which pressure type is not considered in low pressure calculations?

In low pressure calculations within gas systems, upstream pressure is not considered because these calculations typically focus on the pressure conditions downstream of a regulating device or within the appliance itself. The purpose of low pressure calculations is to ensure that gas flow and pressure are maintained appropriately for safe and efficient operation downstream, where combustion or usage occurs.

Thus, low pressure considerations mainly include downstream pressure, which is the pressure at the point of gas delivery to the appliance, as well as other environmental influences. Air pressure, referring to the atmospheric pressure affecting the gas system, and ambient pressure, which is the pressure of the surrounding environment, are also factors that can play a role in calculations. However, the upstream pressure, which is the pressure before it reaches the regulator or appliance, is generally not a focus because it does not have a direct influence on the low pressure functionality of the system downstream.