1. CORE AREA
K. F. Chan (Mr.)
MEBS6002

2. DIVERSITY OF ILLUMINANCE
Core area – area of working plane having a boundary 0.5m from the walls
Maximum to minimum illuminance not to exceed 5:1
K. F. Chan (Mr.)
MEBS6002

3. TASK & SURROUND
K. F. Chan (Mr.)
MEBS6002

4. UNIFORMITY OF LUMINANCE
UNIVERSITY OF HONG KONG
Faculty of Engineering
M.Sc.(Eng) in Building Services
MEBS 6002 Lighting Engineering
UNIFORMITY OF LUMINANCE
Luminance ratio
task to immediate surround – 3:1
task to general background – 10:1
-- therefore, most modern office furniture are light coloured
Task area x 0.5m in front of the observer at the edge of the desk or working surface.
Immediate surround – band with a width of at least 0.5m.
Typical task luminance range is
40 to 120 cd/m2, and seldom exceeds 200cd/m2
K. F. Chan (Mr.)
MEBS6002

5. K. F. Chan (Mr.)
MEBS6002

6. ILLUMINANCE VARIATION
Task area – 0.5m x 0.5m
Minimum to average not less than 0.8
K. F. Chan (Mr.)
MEBS6002

7. UNIFORMITY OF ILLUMINANCE
In general, if the recommended SHR is not exceeded, minimum to average of 0.8 can be achieved
In general, if the mid-point ratio calculated according to CIBSE TM5 does not exceed 0.7, uniformity of 0.8 can also be achieved.
K. F. Chan (Mr.)
MEBS6002

8. SHR
K. F. Chan (Mr.)
MEBS6002

9. MOUNTING HEIGHT
K. F. Chan (Mr.)
MEBS6002