In lighting design, what does the term "footcandle" measure?

The term "footcandle" refers specifically to a unit of measurement for illuminance, which is the amount of light that falls on a given surface area. One footcandle is defined as the illuminance produced by a uniform light source of one candle at a distance of one foot. This measurement is crucial in lighting design as it helps determine how well lit a particular area is, enabling designers to set appropriate lighting levels for different tasks and settings.

Illuminance is essential in ensuring that spaces are sufficiently lit for their intended uses, influencing aspects such as comfort, safety, and functionality. Understanding footcandles allows lighting designers to create environments that meet both aesthetic and performance needs.