Different Lighting LevelsWe need a certain amount of lighting in order to be able to see objects clearly and comfortably.For example, in an office, the industry standard is 500 lumen on desks and other work surfaces. If this lighting level is achieved when there is no additional lighting from windows (at night or late evening), the lighting level from fixtures needs to be reduced when sunlight is present and changed as the amount of sunlight changes (at different times of the day or due to the presence of clouds). The ability to effectively control the amount of lighting from the lighting fixtures as the external daylight changes results in a more comfortable and effective workplace. The attendant energy (and cost) saving is known as daylight harvesting. Lighting levels can be reduced (but still be effective) for cleaning and maintenance during non-office hours. This is the maintenance level. At other times, the lights can be turned off completely or kept on at reduced levels for security reasons.
|