What is NOT a characteristic of low pressure gas equations?

Low pressure gas equations primarily focus on conditions at the point of gas consumption and the implications of those conditions on system performance. One key characteristic is that they generally take the downstream pressure into account, as this is critical for ensuring correct measurements and calculations related to the pressure and flow at the end-use point.

Typically, these equations also involve considerations of excess air, which influences combustion efficiency, and ambient air density, as environmental conditions can affect gas behavior. Excluding upstream pressure represents a fundamental aspect of low pressure equations because they operate under the assumption that conditions downstream are primarily affected by the factors at the end-use point rather than the pressures upstream.

Thus, the correct choice indicates that upstream pressure is not a consideration in low pressure gas equations, which is crucial for understanding how these equations are applied in practical contexts.