Plumbing Darcy Weisbach Head Loss Calculator
Darcy–Weisbach HEAD loss fL/d v²/(2g), actual Darcy—notFanning—factor; not pressurePa output or friction regime determination. Actual independently matched units, regime, material/equipment and governing references; not a hydraulic code, safe pressure, water pot ability or operational approval.
Description
Darcy–Weisbach head loss combines pipe length, bore, mean velocity and Darcy friction factor.
Darcy–Weisbach head loss combines pipe length, bore, mean velocity and Darcy friction factor.1
The returned head differs from pressure and requires a consistent gravity value. The calculation and input requirements are explained below.
When to use Plumbing Darcy Weisbach Head Loss Calculator
Enter nonnegative independently established Darcy factor, pipe length meters and mean velocity m/s, plus positive bore meters and gravity m/s².
How to use Plumbing Darcy Weisbach Head Loss Calculator and how it works
- Prepare the measurements or independently established model inputs described below, with matching units and observation scope.
- Enter the required fields and run Plumbing Darcy Weisbach Head Loss Calculator.
- Read the result fields using the formula, output units, signs and ordering explained below.
- Correct any rejected inputs and rerun; interpret the result within the stated model and its assumptions.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| callerIndependentDarcyFrictionFactor | Caller Independent Darcy Friction Factor. Use the units and matching context stated in the calculation below. | number | Required; nonnegative; finite; other constraints below |
| actualPipeLengthMeters | Actual Pipe Length Meters. Use the units and matching context stated in the calculation below. | number | Required; nonnegative; finite; other constraints below |
| actualInnerDiameterMeters | Actual Inner Diameter Meters. Use the units and matching context stated in the calculation below. | number | Required; strictly positive; finite; other constraints below |
| actualMeanVelocityMetersPerSecond | Actual Mean Velocity Meters Per Second. Use the units and matching context stated in the calculation below. | number | Required; nonnegative; finite; other constraints below |
| callerGravityMetersPerSecondSquared | Caller Gravity Meters Per Second Squared. Use the units and matching context stated in the calculation below. | number | Required; strictly positive; finite; other constraints below |
Enter nonnegative independently established Darcy factor, pipe length meters and mean velocity m/s, plus positive bore meters and gravity m/s². Apply the head-loss formula and return meters. The factor is not calculated and must follow the Darcy rather than Fanning convention.
headLossM=DarcyFactor*(lengthM/diameterM)*velocityMps^2/(2*g) Apply the input ordering, units and branch conditions stated above.
| Output field | Meaning | Value type |
|---|---|---|
| result | Object containing the calculated or selected fields below. | object |
| result.value | Numeric result under the formula and output units explained above. | number |
{
"input": {
"callerIndependentDarcyFrictionFactor": 0.5,
"actualPipeLengthMeters": 2,
"actualInnerDiameterMeters": 1,
"actualMeanVelocityMetersPerSecond": 2,
"callerGravityMetersPerSecondSquared": 2
},
"output": {
"result": {
"value": 1
}
}
}Limitations and assumptions
The calculation uses the supplied observations and model inputs. It does not collect measurements, select a reference population or coefficient, or establish that the model applies to the actual case. The stated branch conditions and output units remain part of the result.
All fields require explicit values. Unexpected fields, wrong types, nonfinite numbers and sparse arrays are rejected. Alignment, bounds and supported-token rules are explained above; extremely large inputs or nonfinite results can also fail. Input errors differ from successful false comparisons, unavailable-domain flags and empty match lists.
EPA documents several friction-headloss methods within hydraulic network analysis. This tool evaluates the supplied Darcy-factor branch and does not compute that factor or solve the network.2
Alternative or Complementary methods
Use Plumbing Valve Pressure Drop From Cv Calculator for a complementary operation: Liquid valve Cv relates flow and pressure drop under its applicable flow branch.
Use Plumbing Relative Roughness Calculator for a complementary operation: Relative roughness compares a pipe's absolute roughness with its internal diameter.
References
-
US EPA: EPANET — US Environmental Protection Agency
Similar or alternative tools
- Plumbing Valve Pressure Drop From Cv Calculator
Liquid valve Cv relates flow and pressure drop under its applicable flow branch.
- Plumbing Relative Roughness Calculator
Relative roughness compares a pipe's absolute roughness with its internal diameter.