lux
Average light level on the relevant task area.
← BACK TO STUDIOThe right light.
LIGHTING KNOWLEDGE / PROJECT PLANNING
The right light.
Starts with the right numbers.
Choose your reference, then find the space you are designing.
Indoor tasks, sports facilities and Abu Dhabi exterior lighting.
Three guides.
One clear starting point.
References reflect the supplied editions. Select the applicable project criteria before using a value.
2022 EDITION
Minimum uniformity for this task from its SLL schedule row.
LIMITING GLARE · UGR
MINIMUM COLOUR RENDERING · Ra / CRI
SURROUND UNIFORMITY · U₀≥ 0.40
Apply the selected U₀ to the task or activity area. For electric lighting, the immediate surrounding band (at least 0.5 m wide) has U₀ ≥ 0.40; the background area has U₀ ≥ 0.10 (§3.1.3.4–3.1.3.6).
ADDITIONAL SLL CRITERIA
Values from the selected task row. A dash means no fixed value is listed.
- Modified maintained illuminance
- Cylindrical illuminance · Eₘ,z
- Wall illuminance · Eₘ,wall
- Ceiling illuminance · Eₘ,ceiling
WHEN TO USE THE MODIFIED VALUE
The modified column addresses context such as critical or prolonged work, low contrast, limited daylight or reduced visual capacity (§3.1.3.3). Select it through a project assessment; it is not an automatic replacement for the required value. Wall and ceiling illuminance use U₀ ≥ 0.10 (§3.1.2.3); cylindrical illuminance also uses U₀ ≥ 0.10 (§3.1.6.2).
COLOUR TEMPERATURE · CCT
SURFACE REFLECTANCE · GENERAL SLL GUIDANCE
Use realistic material reflectances in the lighting model. These ranges apply to major diffuse interior surfaces; they are not different for each industry (§3.1.2.2, p. 32).
- Ceiling reflectance · ρ
- 0.70–0.90
- Wall reflectance · ρ
- 0.50–0.80
- Floor reflectance · ρ
- 0.20–0.60
OTHER SURFACES
Furniture and major objects: ρ = 0.20–0.70. Clear interior glass: typical reflectance 0.10. Use the actual finish where known; reflectance is not a maintenance factor.
DERIVED DESIGN CHECKS
INSTALLATION & ASSESSMENT
Apply the selected task criteria to its assessment plane. Coordinate luminaire mounting, glare control and maintenance with the room and activity; the schedule does not prescribe a universal mounting height.
APPLICATION NOTE
ADDITIONAL TABLE GUIDANCE
EDITION & PAGE
Reference targets are from the supplied SLL Code for Lighting 2022. They are design criteria, not a prediction of achieved illuminance. Use a lighting model and a justified maintenance factor to verify the installation. A dash means no fixed value is specified; read all task notes and confirm the project assessment plane.
No matching area.
Try a broader search or another industry. Specialist areas need a project-specific review.
Ask about your space ↗THE COMPLETE SCHEDULE / ALL AREAS & INDUSTRIES
Every space.
Find its requirements.
Use the filters above to narrow the schedule. Select an area below to see its application notes.
| Industry / category | Area / visual task | Lux | U₀ | UGR | Ra / CRI |
|---|
— = no fixed value specified. Lux, U₀, UGR and Ra belong to the selected task row. Open a task for modified lux, CCT, wall/ceiling criteria, reflectance guidance and application notes.
02 / UNDERSTAND THE NUMBERS
Lux is the amount.
Illuminance measures light arriving on a surface. A maintained value allows for the reduction in performance over the maintenance period; it is not simply the initial output of new fittings.
Uniformity is the balance.
U₀ compares the lowest point to the average on the same assessment grid. At an average of 500 lux, U₀ = 0.60 corresponds to a minimum of 300 lux. Use the task-specific value from the SLL schedule; immediate-surround and background guidance is separate.
The task sets the target.
Storage, detailed inspection and reading need different conditions. The measurement plane matters too: a vertical rack face is different from a horizontal desk.
About this SLL 2022 guide
The 53 indoor workplace tables in §3.2 contain 328 searchable tasks and subtasks across industrial processes, offices, education, healthcare, hospitality, public buildings, retail and transport. Required and modified maintained illuminance remain separate; printed dashes remain unspecified.
Task criteria are cited by table, reference and printed page. General reflectance guidance is from §3.1.2.2 (p. 32); surrounding/background illuminance and uniformity from §3.1.3.4–3.1.3.6 (pp. 34–36); colour-temperature groups from §3.1.7.2 (p. 45). CCT is presented as a task requirement only where the task note states one. The Sports and ADM guides retain their supplied editions.
EDITION & SOURCE
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