Fan System Curve Calculator
Declared calibrated fan static pressure kQ², same density/flow conditions; no flow selection, fan curve intersection or motor rating. Actual independently established compatible SI units/model context; conditional arithmetic, not code compliance, engineering design or safe operation approval.
Description
A quadratic fan-system model relates static pressure to flow using an independently calibrated resistance.
A quadratic fan-system model relates static pressure to flow using an independently calibrated resistance.1
This tool evaluates that curve without selecting flow or finding a fan-curve intersection.
When to use Fan System Curve Calculator
Use this tool to evaluate that curve without selecting flow or finding a fan-curve intersection.
How to use Fan System Curve Calculator and how it works
- Prepare callerCalibratedFanSystemResistance, actualAirFlow, with the units, conventions and assumptions below.
- Enter the required fields and run Fan System Curve Calculator.
- Read result.value using the output definitions below.
- Correct any rejected inputs and rerun; interpret the result within the stated model and its assumptions.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| callerCalibratedFanSystemResistance | Caller Calibrated Fan System Resistance. Use the units and matching context stated in the calculation below. | number | Required; nonnegative; finite; other constraints below |
| actualAirFlow | Actual Air Flow. Use the units and matching context stated in the calculation below. | number | Required; nonnegative; finite; other constraints below |
Supply nonnegative quadratic resistance coefficient and nonnegative flow in its matching unit convention. Return coefficient*flow^2 as the corresponding pressure rise or drop magnitude. Static pressure and the fan performance curve are not included.
systemPressure=coefficient*flow^2 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 | Quadratic system pressure in the supplied coefficient's compatible pressure unit. | number |
{
"input": {
"callerCalibratedFanSystemResistance": 1,
"actualAirFlow": 2
},
"output": {
"result": {
"value": 4
}
}
}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.
Alternative or Complementary methods
Use Pump System Curve Calculator for a complementary operation: A quadratic pump-system curve separates static head from flow-dependent resistance.
Use Equal-Friction Duct Sizing Calculator for a complementary operation: Equal-friction duct sizing depends on flow, roughness, section shape and a chosen pressure gradient.
References
-
Fan System Curve Calculator — tool.io
Similar or alternative tools
- Pump System Curve Calculator
A quadratic pump-system curve separates static head from flow-dependent resistance.
- Equal-Friction Duct Sizing Calculator
Equal-friction duct sizing depends on flow, roughness, section shape and a chosen pressure gradient.