A task plane is the surface where illuminance is being assessed.
A task plane is the surface used for the lux assessment, such as a floor, desk, bench, shelf, wall or display face.
Technical meaning
A task plane is the named surface where illuminance is assessed, such as a benchtop, desktop, floor route, shelf face or display wall.
The plane can be horizontal, vertical or inclined. Its height and orientation affect area, beam geometry and the meaning of the lux result.
Task plane and room zoneThe calculation belongs to one assessed plane inside one zone, so area, target lux and later count stay together.
Calculation use
Lux-to-lumens and room estimates need the task-plane area because lux is lumens per square metre on that plane.
Beam and spacing estimates use task-plane height to calculate effective height from the luminaire to the assessed surface.
Not the same as
The task plane is not always the floor. A kitchen bench, desk or vertical display can be the relevant assessment surface.
The task plane is not the full project scope. Glare, uniformity, vertical contrast, daylight and controls may need separate records.
Australian context
Australian calculator notes should state the selected task plane so room, workplace and downlight estimates are not read as whole-space compliance results.
Examples
Example
Value
Planning note
Kitchen bench
0.9 m plane height
Use the bench area for task lighting rather than the full floor area.
Office desk
0.72 m plane height
Screen position and glare remain separate checks.
Circulation floor
0 m plane height
Appropriate when the movement surface is the assessed plane.
The task-plane definition supports calculator consistency. Applications tied to Australian lighting documents still need the relevant task description and reference pathway.