Lighting Technology

The illuminance recommended for a specific type of activity will depend partly on the nature of that activity(principally its visual difficulty) and partly on the design of the interior concerned (particularly the lightness of the surroundings). The table below gives recommended illuminance , based on the scale defined above, for different areas and activities. The values given are average maintained illuminance over the task area. There fore the illuminance may not fall below these values, no matter what the age of the installation. The values are valid for normal visual conditions and take into account the following factors: - requirements for visual tasks -safety -psycho-physiological aspects such as visual comfort and well being -economy -practical experience The illuminance should be increased, when: -unusually low reflectances and /or contrasts are present for the task -visual work is critical -errors are costly to rectify -accuracy or higher productivity is of