Question

The International Building Code requires you to provide one foot-candle of light at the ground surface along the path of egress from the building you are designing to the public way. In order to get a sense of how much light this is, you might compare it to moonlight. About how much light does a full moon provide on a clear night: one-half foot-candle, one foot-candle, or two foot-candles?

Answer

We cannot rely on the moon to provide the required lighting, but if we could, it would only provide about half the required light — about one-half foot-candle — when it is at its fullest.