Technical meaning
- The lumen method estimates average illuminance or required lumens for a defined area and assessed plane.
- It uses broad delivery assumptions, especially utilisation factor and maintenance factor, rather than detailed point-by-point photometric modelling.
Calculation use
- The method supports early lux-to-lumens, room-lighting and workplace-lighting estimates.
- It is useful for testing sensitivity: changing target lux, UF or MF quickly shows how the lumen allowance moves.
Not the same as
- The lumen method is not a complete lighting design note. It does not prove uniformity, glare, vertical illuminance or detailed point values.
- It is not a replacement for project-specific standards review where workplace, public-space or safety-critical lighting is involved.
Australian context
- Australian calculations should name the task plane, target basis and source boundary before a lumen-method result is used in a room or workplace note.
Examples
| Example | Value | Planning note |
|---|---|---|
| Room estimate | target lux x area / UF / MF | The result becomes a required lumen allowance. |
| UF sensitivity | 0.70 vs 0.60 | Lower delivery assumptions increase the lumen allowance. |
| MF sensitivity | 0.80 vs 0.70 | Dirt, ageing and maintenance uncertainty change maintained-light estimates. |
Calculation limits and records
- This site uses the lumen method for preliminary estimates. Formal design decisions need the applicable Australian standards pathway, luminaire data and project evidence.