Lighting · 21 July 2026 · For contractors and project engineers
"How many lux?" sounds like it should have a one-word answer, but a compliant lighting design is never a single number. BS EN 12464-1 sets a maintained illuminance for each task — and a glare limit, a uniformity and a colour-rendering requirement to go with it. Here are the numbers people ask for, and the three things a lux figure alone leaves out.
| Area / task | Maintained lux (Em) | UGR limit |
|---|---|---|
| General office (writing, typing, reading) | 500 | ≤ 19 |
| Reception / filing | 300 | ≤ 22 |
| Meeting / conference room | 500 | ≤ 19 |
| Corridors / circulation | 100 | ≤ 25 (28) |
| Stairs | 100–150 | ≤ 25 |
| Warehouse storage (stacking) | 150 | — |
| Order picking / continuous work | 300 | ≤ 22 |
| Loading bay | 150 | ≤ 25 |
Indicative values for common tasks — the standard lists many more, and the current edition adds context (task, immediate surround and background areas) with modifier ranges. Always design to the specific task and the current BS EN 12464-1.
The current standard also sets minimum levels on the walls and ceiling and considers cylindrical illuminance for faces and visual communication — lighting the room, not just the desk.
"Maintained" is the key word. Lamp output falls with age and fittings collect dust, so the illuminance on day one has to be higher than the target for it to still be met at the end of the maintenance cycle. That headroom is the maintenance factor (MF) — design to Em / MF initially. A design quoted at exactly the target with no maintenance factor is already non-compliant the moment the lamps depreciate.
Meeting all four criteria — lux, uniformity, glare and colour rendering, with a realistic maintenance factor — is a calculation on the actual room, luminaire and layout, not a spacing rule. Our DIALux lighting design service produces illuminance and UGR calculations to BS EN 12464-1 with the maintenance factor stated, and covers emergency lighting to BS 5266 alongside the normal scheme.
BS EN 12464-1 sets 500 lux maintained for general office work — writing, typing, reading and data processing — with a glare limit of UGR ≤ 19, uniformity Uo ≥ 0.6 and colour rendering Ra ≥ 80. Reception desks and filing areas are typically 300 lux, and archives around 200 lux.
Around 150 lux maintained for storage and stacking areas that are not continuously occupied, rising to about 300 lux for order-picking and areas where people work continuously. Loading bays are typically 150 lux. Continuously occupied spaces have a minimum of 200 lux under the current standard.
The illuminance (Em) that must be maintained on the task area over the whole maintenance cycle — not the day the lamps are new. Because output falls as lamps age and fittings collect dirt, you design to a higher initial level and apply a maintenance factor so it never drops below the target before the next clean or re-lamp.
Unified Glare Rating — a measure of discomfort glare from the luminaires in a space. BS EN 12464-1 sets a limit for each task (for example UGR ≤ 19 in offices, ≤ 22 in many industrial areas). A compliant lighting design has to meet the glare limit as well as the lux level.
Circulation areas and corridors are typically 100 lux maintained, and stairs around 100–150 lux with attention to modelling so the steps read clearly. These are lower than task areas but still have uniformity and glare requirements.