The light or the level of illuminance is the total flux of light on a surface per unit area. The area, often referred to as “the work plane” is the space where the lighting is mostly required for, such as a work space, for example.
Outdoor light levels on a clear day are of 10 000 lux, inside buildings, the offices near the windows are close to 1 000 lux. If you move towards the middle area of the building, we can measure numbers as low as 25 to 50 lux. So, lighting is a necessity for such low levels, but how to measure the levels required?
Depending on the type of activities performed in a specific room, you have different recommended light levels. For example, for normal activities, we are looking at 500 to 1000 lux. And, for work related operations requiring more precision, you can go up to 1500 to 2000 lux.
Here is a quick chart from the engineer tool box1 for recommended levels of illuminance depending on the environment and activities related:
|Heavy reading & work spaces||500-1200|
|High detail workshop||1000-2000|
|Institutional & Office Spaces||Illumination|
|Hallways & stairways||150-300|
|General exercise in gymnasium||300-400|
|Basketball in gymnasium||750-1000|
|Meeting rooms and auditoriums||100-200|
|Open space offices||500-750|
|Public areas with dark surroundings||20 - 50|
|Simple orientation for short visits||50 - 100|
|Working areas where visual tasks are only occasionally performed||100 - 150|
|Warehouses, Homes, Theaters, Archives||150|
|Easy Office Work, Classrooms||250|
|Normal Office Work, PC Work, Study Library, Groceries, Show Rooms, Laboratories||500|
|Supermarkets, Mechanical Workshops, Office Landscapes||750|
|Normal Drawing Work, Detailed Mechanical Workshops, Operation Theaters||1,000|
|Detailed Drawing Work, Very Detailed Mechanical Works||1500 - 2000|
|Performance of visual tasks of low contrast and very small size for prolonged periods of time||2000 - 5000|
|Performance of very prolonged and exacting visual tasks||5000 - 10000|
|Performance of very special visual tasks of extremely low contrast and small size||10000 - 20000|
There are many tools available online to obtain light level recommendations or software using IES files, but your simplest bet is to contact a lighting specialist you trust.