Formula & worked example
Qv=m·v_specific; A=Qv/V; D=sqrt(4A/π).
1,000 kg/h steam at 0.2 m³/kg occupies 0.0556 m³/s; at 25 m/s it needs about 53 mm hydraulic diameter.
Plant engineering calculator · Updated Sep 17, 2026
Steam Pipe Sizing Calculator — Mass Flow, Specific Volume, Velocity & Diameter
Size a steam line from mass flow, entered steam specific volume and target velocity, or check velocity for an entered inside diameter.
Inputs
Live engineering result
Volumetric steam flow 0.055555556 m³/s
Required flow area 0.0022222222 m²
Required hydraulic diameter 53.192304 mm
Velocity in entered pipe 12.575205 m/s
Entered pipe is at/below target velocity
Assumptions & limits
- Enter specific volume from verified steam properties at the design pressure/condition.
- Final sizing must also check pressure drop, drainage, startup and waterhammer risk.
Frequently asked questions
What does this Steam Pipe Sizing Calculator calculate?
Size a steam line from mass flow, entered steam specific volume and target velocity, or check velocity for an entered inside diameter.
Can I use the result for equipment selection?
Use the result as an engineering screening and cross-check. Confirm final selections against manufacturer performance data, design conditions, applicable standards and local code.
Why does MAXScanner show assumptions?
Plant calculations can move materially with pressure, temperature, fluid properties, diversity and operating conditions. Visible assumptions make the result auditable.