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How much light do I need?

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:

 
Home areasIllumination
(lux, lumen/m2)
Light reading 300-500
Heavy reading & work spaces 500-1200
Kitchen 300-550
Dining room 200-300
Laundry room 200-550
High detail workshop 1000-2000
Institutional & Office SpacesIllumination
(lux, lumen/m2)
Hallways & stairways 150-300
Storage rooms 100-500
Classrooms 250-550
Offices 300-750
Restrooms 150-300
General exercise in gymnasium 300-400
Basketball in gymnasium 750-1000
Meeting rooms and auditoriums 100-200
Library 300-500
Maintenance room 300
Science labs 300-500
Woodworking shop 300-750
Open space offices 500-750
ActivityIllumination
(lux, lumen/m2)
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.

1 http://www.engineeringtoolbox.com/light-level-rooms-d_708.html

September 8, 2017