Calculation method
Velocity assessment is a preliminary screen, not a pipe design approval. Steam reference bands: GESTRA steam line sizing (saturated 20–40 m/s; superheated 35–65 m/s). Hydronic water: Caleffi (2–4 ft/s). Thermal oil defaults to an editable project assumption of 2–4 m/s. These ranges do not apply universally to suction lines, heater coils, wet steam or all industrial water services.
A = π D² / 4 · Q = ṁ / ρ · u = Q / A
D is the internal diameter in m, ṁ is mass flow in kg/s, ρ is density in kg/m³ and Q is actual volume flow in m³/s. Saturated steam uses dry saturated vapor properties (x = 1); its temperature is determined by pressure. Superheated steam uses pressure and temperature. Liquid water must be below its saturation temperature at the selected pressure.
Steam and water properties use the same IAPWS-IF97 engine as Steam Properties and Water Properties. Thermal oil density is interpolated from the selected oil property table; any extrapolation is identified in the result.
Standard steel pipe sizes: DN 15–800 where Schedule 40 or 80 is defined. Schedule 80 is available up to DN 600; DN 550 supports Schedule 80 only, and DN 800 supports Schedule 40 only. Nominal internal diameter is calculated as OD − 2 × wall thickness using ASME B36.10M reference dimensions and Wheatland pipe tables. Use manual entry for a measured bore or other pipe dimensions.
This calculation gives average velocity at the specified local conditions. It does not calculate pressure drop, pipe wall thickness or two-phase flow. Use actual volume, rather than normal or standard volume, for volumetric flow inputs.