Lighting Engineering

Luminaire Utilization Factor (UF) from Photometric Data and Room Geometry calculator

Luminaire Utilization Factor (UF) from Photometric Data and Room Geometry engineering calculator.

Runnable This tool can run, but independent engineering verification has not been established.

Quick Answer

The luminaire utilization factor (uf) from photometric data and room geometry calculator computes luminaire utilization factor (uf) from the input values you provide.

Calculator

Luminaire Utilization Factor (UF) (dimensionless)
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Result Interpretation

Luminaire Utilization Factor (UF) from Photometric Data and Room Geometry calculator computes Luminaire Utilization Factor (UF) in dimensionless using the defined engineering formula and the input values provided. Luminaire Utilization Factor (UF) is expressed in dimensionless. No universal acceptance threshold is defined by this calculator.

Worked Example

Verified calculation

Given:

  • Floor Cavity Ratio = 0.8
  • Wall Cavity Ratio = 1.2
  • Ceiling Cavity Ratio = 0.6
  • Luminaire Efficiency = 0.72
  • Reflectance Correction Factor = 0.94

Expected Result:

  • Luminaire Utilization Factor (UF) = 0.0012146894931324

Engineering Interpretation:

Under the given input conditions, the calculated result is: Luminaire Utilization Factor (UF) = 0.0012146894931324 dimensionless.

The actual numerical result is computed by the Runtime engine using the persisted tool definition. The values shown here come from deterministically validated test cases.

Formula / Method

UF = (1.0 - pow(0.9, floor cavity ratio)) * (1.0 - pow(0.85, wall cavity ratio)) * (1.0 - pow(0.8, ceiling cavity ratio)) * luminaire efficiency * reflectance correction factor

Luminaire Utilization Factor (UF).

Variables

SymbolLabelRoleDescription
cavity_ratio_floor Floor Cavity Ratio INPUT Floor Cavity Ratio
cavity_ratio_wall Wall Cavity Ratio INPUT Wall Cavity Ratio
cavity_ratio_ceiling Ceiling Cavity Ratio INPUT Ceiling Cavity Ratio
luminaire_efficiency Luminaire Efficiency INPUT Luminaire Efficiency
reflectance_correction_factor Reflectance Correction Factor INPUT Reflectance Correction Factor
result Luminaire Utilization Factor (UF) OUTPUT Luminaire Utilization Factor (UF)

Calculation Steps

  1. Enter the floor cavity ratio in dimensionless.
  2. Enter the wall cavity ratio in dimensionless.
  3. Enter the ceiling cavity ratio in dimensionless.
  4. Enter the luminaire efficiency in dimensionless.
  5. Enter the reflectance correction factor in dimensionless.
  6. Step 1: Compute luminaire utilization factor (uf).
  7. Read the luminaire utilization factor (uf) (dimensionless) from the results.

Frequently Asked Questions

What does this calculator calculate?

The Luminaire Utilization Factor (UF) from Photometric Data and Room Geometry calculator estimates Luminaire Utilization Factor (UF) based on the input parameters you provide

Why is floor cavity ratio important in this calculation?

floor cavity ratio is used directly in the calculation of luminaire utilization factor (uf). Its effect on the result depends on the complete formula and the values of the other inputs.. When you enter floor cavity ratio in dimensionless, the calculator uses it in the engineering formula to compute the output

How should I interpret the result luminaire utilization factor (uf)?

The calculator outputs luminaire utilization factor (uf) in dimensionless. The result is computed directly from the input values using the defined engineering formula

What units should I use for the inputs?

Enter each value in the units shown next to the input field: Floor Cavity Ratio (dimensionless), Wall Cavity Ratio (dimensionless), Ceiling Cavity Ratio (dimensionless), Luminaire Efficiency (dimensionless), Reflectance Correction Factor (dimensionless). Make sure all inputs use the specified units for consistent results

What assumptions does this calculator use?

This calculator uses automatically validated engineering formulas. Results are approximate and should be validated against site-specific conditions, applicable codes, and professional engineering judgment

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