What is the minimum average illumination provided by artificial light for adequate illumination at a height of 30 inches above the floor level?

The minimum average illumination for adequate visibility at a height of 30 inches above the floor level is typically recognized as 10 footcandles. This level of illumination is considered sufficient for most commercial environments, ensuring that tasks can be performed safely and effectively without straining the eyes.

When considering lighting requirements in commercial spaces, various factors play a role, including the nature of the work being done, the layout of the space, and potential safety hazards. For general purposes, including areas where people walk and perform basic office tasks, the established standard of 10 footcandles provides a balance of brightness without causing glare or excessive energy consumption.

In contrast, higher levels of illumination, such as 15 or 20 footcandles, may be applicable in specific situations where tasks require greater visual acuity, but they are not the baseline requirement. Therefore, knowing that the minimum standard is 10 footcandles emphasizes the importance of compliance with lighting regulations, creating a comfortable and functional environment for occupants.