The Illuminating Engineering Society (lES) recommends a range of footcandle levels to ensure adequate illumination and safety for occupants.
A footcandle is defined as the illumininance on one square foot surface from a uniform light source. Below is a guideline for common modular builduing applications to assist in achieving appropriate light levels with the greatest energy‐efficiency. The required light levels are indicated in a range because different tasks require different amounts of light. In general, low contrast and detailed taks require more light while high contrast and less detailed tasks require less light.