Technical meaning
- Lux describes light arriving at the assessed plane, not the total light leaving a lamp or luminaire.
- One lux equals one lumen distributed over one square metre. The measured plane might be a floor route, kitchen bench, desk, shelf face or other surface named in the lighting record.
Calculation use
- For early lumen allowances, lux is multiplied by area and then adjusted for utilisation and maintenance assumptions.
- For checking an installed group, delivered lumens are divided by the assessed area after the same delivery assumptions are applied.
Not the same as
- Lux is not wattage. A lower-wattage LED can produce a higher or lower lux result depending on output, optics and spacing.
- Lux is not a complete lighting design record. Uniformity, glare, vertical surfaces, controls, emergency scope and measured evidence sit outside a single average value.
Australian context
- Australian room and workplace notes should name the task plane and whether the value is a preliminary planning target, a measured reading or a maintained-lighting estimate.
Examples
| Example | Value | Planning note |
|---|---|---|
| Kitchen bench | 300-500 lx planning range | Read at the benchtop, not averaged across the whole kitchen floor. |
| Internal circulation | 50-150 lx planning range | Movement and orientation generally need a different record from detailed task work. |
| Desk or work area | 300-500 lx planning range | Screen glare, daylight direction and the maintained basis still need separate notes. |
Calculation limits and records
- Formula pages can define lux and lumen relationships. Workplace, public-space and emergency-lighting decisions need the relevant Australian documents and project records beside the arithmetic.