International Standards and Conformity Assessment for all electrical, electronic and related technologies
Main title

SI Zone

International System of Units

 

Light

This section describing the SI units for light is covered in ISO 80000-7.

 

Luminous intensity, I

candela, cd

Luminous flux, Φ

lumen, lm; 1 lm = 1 cd/sr

Illuminance, E

lux, lx; 1 lx = 1 lm/m2 = 1 cd/(sr · m2)

Light exposure, H

lux second, lx · s; 1 lx · s = 1 s · cd/(sr · m2)


Conversion factors

1 lx · h = 3,6 klx · s