HVAC common-velocity fitting loss calculator

Calculate combined loss coefficient and total fitting pressure loss with your own figures.

Your numbers

Use the units shown. Results update as you change valid inputs.

Use combined loss coefficient and total fitting pressure loss to compare changes to your inputs. The method and limits below explain the scope.

Examples

Examples

Try the starting example

Fitting loss coefficients K
0.4,0.8,1.2
Air density (kg/m³)
1.2
Reference velocity (m/s)
5
Combined loss coefficient
2.4
Total fitting pressure loss (Pa)
36

Try another scenario

Fitting loss coefficients K
[1.4, 0.8, 1.2]
Air density (kg/m³)
1.2
Reference velocity (m/s)
5
Combined loss coefficient
3.4
Total fitting pressure loss (Pa)
51
Calculation method

Calculation method

Combined loss coefficient

Sum K coefficients at one common reference velocity; Δp=ΣKρv²/2.

Total fitting pressure loss (Pa)

Sum K coefficients at one common reference velocity; Δp=ΣKρv²/2.

Symbols and units
a
Fitting loss coefficients K
b
Air density (kg/m³)
c
Reference velocity (m/s)

Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.

Assumptions & limits

Assumptions & limits

  • User-supplied measurements and assumptions; Sum K coefficients at one common reference velocity; Δp=ΣKρv²/2. Supported limits: Finite numeric values bounded to 1e9 magnitude; lists and tables contain 1–100 records unless a stricter bound is stated. Inputs use the units shown. Lists explicitly paired by a method must have matching lengths; independent polynomial coefficient vectors may differ. Respect stated physical, interpolation, policy and computational domain limits.
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Further reading

Method reference ↗

Background reading; this does not imply endorsement or independent review of SumFizz.

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