EN 12464-1 lists hundreds of lux targets. SBC 401 in Saudi Arabia references most of them. Here is the practical sub-set that decides whether your office, mosque, hospital, or mall actually passes commissioning.
Four ideas to carry into the next specification conversation you have.
EN 12464-1 specifies maintained illuminance Em on the task area, not on the ground. Always design to the work plane height: 0.75 m desk, 1.0 m mosque, 0.85 m retail.
Em is the value at end of maintenance cycle, after dirt and depreciation. Initial install lux is typically ~30% higher to allow for it.
Uo = Emin / Eavg. EN demands Uo > 0.6 for offices, > 0.4 for circulation. Patchy lighting fails even if average is on target.
Unified Glare Rating ≤ 19 for offices, ≤ 22 for classrooms, ≤ 25 for retail. Above 25, occupants complain.
Maintained illuminance Em, work-plane height, per EN 12464-1 cross-referenced with SBC 401.
| Space | Em (lux) | Reference |
|---|---|---|
| Office desk | 500 | EN 12464-1 §5.26 |
| Office circulation | 100 | EN 12464-1 §5.1 |
| Mosque main prayer hall | 200 | SBC 401 / SASO |
| Mosque ablution / wudu | 150 | SBC 401 |
| Classroom (general) | 300 | EN 12464-1 §5.36 |
| Classroom (drawing board) | 500 | EN 12464-1 §5.36 |
| Hospital ward (general) | 100 | EN 12464-1 §5.46 |
| Hospital examination | 1,000 | EN 12464-1 §5.46 |
| Operating theatre (cavity) | 10,000–100,000 | EN 12464-1 §5.46 |
| Mall walkway | 150–200 | IES RP-3 |
| Mall focal retail | 750–1,500 | IES RP-3 |
| Warehouse aisle (manual) | 200 | EN 12464-1 §5.50 |
| Warehouse aisle (high-rack) | 300 | EN 12464-1 §5.50 |
| Car park (covered) | 75 | EN 12464-2 |
| Street (residential road) | 5–10 (avg) | CIE 115 · ME6 |
| Street (main arterial) | 20–30 (avg) | CIE 115 · ME2 |
Five practical rules that turn a number into a passing installation.
EN 12464-1 maintenance factors (MF) typically range 0.7–0.85. A 500 lux office target means designing initial install to ≈ 600 lux. Without MF in the DIALux model, you pass commissioning and fail year five.
Two designs both averaging 500 lux: one with Uo = 0.7, one with Uo = 0.35. The second fails EN 12464-1 even though the average matches. Lay out fixtures on a grid sized to ≤ 1.5× mounting height for even spread.
DIALux defaults assume 70/50/20 (ceiling/wall/floor). A real office with grey carpet and dark walls runs 50/30/10, a 15% lux drop for the same fixture count. Measure actual surfaces before finalising.
The work plane in a mosque is the floor, not a desk, but mats have low reflectance (~0.15 vs 0.40 for carpet). Em on the mat surface is what worshippers experience. Spec to mat-level lux, not 1 m above floor.
CIE 115 specifies maintained average and minimum lux on the carriageway. A pole giving 30 lux peak but 3 lux between poles fails. Lighting class is decided by traffic density, conflict areas, and surrounding ambient, not by intent.
We don't quote until we model. Every NLC submission includes a DIALux report showing Em, Uo, UGR per space, against EN 12464-1.
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