Two quotations showing the same m³/h figure do not necessarily supply the same quantity of gas. Volumetric flow depends on temperature, absolute pressure and real-gas behavior.
Actual operating flow is often written as m³/h or Am³/h; an unqualified m³/h label is insufficient. Nm³/h and Sm³/h express volume reduced to specified reference conditions. Even the common normal basis of 0 °C and 1.01325 bar(a) must be confirmed; standard temperature is not identical in every document.
For the same gas composition and moisture basis, Q₂ = Q₁ × (P₁/P₂) × (T₂/T₁) × (Z₂/Z₁). P is absolute pressure, T is temperature in kelvin and Z is the compressibility factor. Do not insert gauge pressure directly: absolute pressure equals gauge pressure plus local atmospheric pressure.
At the same absolute pressure, using the ideal-gas approximation, 100 m³/h referenced to 0 °C becomes approximately 107.3 m³/h referenced to 20 °C. This is not additional production; it describes the same molar flow using a different volume. The example assumes dry gas. Accurate or high-pressure calculations require appropriate composition and Z data.
Request gas identity and composition, purity definition, reference temperature and pressure, dry or wet basis, delivery pressure and measurement location. Unit conversion does not replace generator capacity corrections for different site conditions. Share quotation and measurement conditions with Mentis to assess gas flows at a common reference.
