with conventional ballasts and the replaced T5 light fittings using
electronic ballasts, respectively. It can be seen that T5 light fittings
with electronic ballasts tend to have higher illuminance levels. The
illuminance levels were measured ranging from 269 to 551 lx with
an average value of 430 lx when T8 lamp fittings were being used.
The mean value is 70 lx less than the recommended illuminance level
of 500 lx for teaching workshop and the reason is due probably
to the decline in lamp output and the gathering of dust on the luminary
over a certain period of time.