Lamp Lumen Required (Ll):

\[ Ll = \frac{Li \cdot Af}{CU \cdot SF} \]

Where:

• \(Ll\) is the lamp lumen required in lumens.
• \(Li\) is the light intensity in foot candles.
• \(Af\) is the floor area in square feet (ft²).
• \(CU\) is the coefficient of utilization (0.04 to 0.72).
• \(SF\) is the service factor (typically 0.7).