12.1.2.3-7 Task Area Luminance Ratios

To ensure effective visual performance, the task area luminance ratios in Table 12.2 should not be exceeded.

Additional Information: To determine task lighting requirements, it is necessary to consider the levels of lighting that surround a task. Great disparities between task and background lighting can lead to adaptation problems.0700

 

Table 12.2 Maximum Task Area Luminance Ratios

 

Areas

Luminance Ratio

Task area versus adjacent darker surroundings

3:1

Task area versus adjacent lighter surroundings

1:3

Task area versus more remote darker surfaces

10:1

Task area versus more remote lighter surfaces

1:10

Luminaires versus surfaces adjacent to them

20:1

Anywhere within normal field of view

40:1