What EN 12464-1 covers
EN 12464-1 specifies what a lighting installation has to deliver for the people working under it — visual comfort and visual performance for observers with normal or corrected-to-normal vision — not how to build it. The Belgian guide marks the boundary: it does not directly set out to secure the safety and health of workers in every specific situation, though a good design under it contributes to a safe working environment.
The current edition is 2021, and it is the version a specification means unless it names an older year. BSI published the British adoption as BS EN 12464-1:2021 on 31 August 2021; the German edition of DIN EN 12464-1 is dated November 2021.
You will rarely see the bare EN number on a tender. Each national standards body republishes the same European text under its own prefix, number and year unchanged: NBN EN 12464-1 in Belgium, BS EN 12464-1:2021 in the UK, DIN EN 12464-1 in Germany, NEN-EN 12464-1:2021 in the Netherlands — four names for one document.
The Belgian reading throughout this page comes from IBE-BIV, Guide pratique de l’éclairage des lieux de travail intérieurs, November 2023, supported by the Belgian FPS Economy: https://ibe-biv.be/wp-content/uploads/2023/11/IBE-BIV-NBN-EN-12464-1-2021-Guide-pratique-de-leclairage-des-lieux-de-travail-interieurs-adjust.pdf — British publication date: https://knowledge.bsigroup.com/products/light-and-lighting-lighting-of-work-places-indoor-work-places-2
The quantities the standard sets
The standard describes a room as zones and sets its numbers per zone, not per room. Four quantities cover the task; three more cover the surfaces around it.
Maintained illuminance (Ēm), in lux
Ēm is the average illuminance the installation has to hold on the reference surface. “Maintained” is the load-bearing word: every target illuminance in the standard is a value to be maintained, so it must still be reached at the end of the installation’s life, after lamps have aged and surfaces have collected dirt. A design starts above the target, and the maintenance factor — the fraction of the new installation’s output you still count on at the end of its life — carries the gap.
Uniformity (Uo)
Uo is a minimum uniformity of illuminance inside a zone, so a zone cannot reach its average by being bright at one end and dark at the other. It is set per zone: at least 0.40 in the immediate surrounding area, at least 0.10 on background, walls and ceiling. Task values are stricter — 0.60 for ordinary office work, 0.70 for technical drawing.
Glare limit (RUGL), on the UGR scale
RUGL is the highest Unified Glare Rating the installation may reach. The limits form a short series — 16, 19, 22, 25, 28 — in steps of 3, because that step represents a noticeable change in glare. The class, not the decimal, is the unit: a design lands in the ≤ 19 class when the calculated value falls between 16.5 and 19.4. The 2021 edition renamed the quantity from UGR to RUG and RUGL without changing the formula. A UGR figure counts as a compliance result only when it comes from the standard’s tabular method; where the formula is used because the table does not fit, ZVEI notes the value is not proof that the limits are complied with.
Colour rendering (Ra)
Ra is the minimum colour rendering index for the activity. Across the office rows it is 80 throughout — the same for filing as for technical drawing — so it is a floor you may not go under rather than a number that picks between two luminaires.
Task area, immediate surrounding area, background
The three zones sit inside each other. The task area carries the full requirement. Around it is the immediate surrounding area, a band at least 0.50 m wide in the working plane: its illuminance is a ratio of the task value, capped at 500 lx and floored at 150 lx, Uo at least 0.40. Around that is the background, a band at least 3 m wide or running to the wall, at a third of the immediate surrounding illuminance, Uo at least 0.10.
Cylindrical, wall and ceiling illuminance
Since 2021 the same tables also carry three room quantities: mean cylindrical illuminance Ēm,z, wall illuminance Ēm,wall and ceiling illuminance Ēm,ceiling. Cylindrical illuminance measures light arriving on a small vertical cylinder instead of on the horizontal plane, which decides whether faces read well across a desk; CIBSE puts the useful range at 50 to 150 lux for good visual communication and recognition of objects. Modelling — the balance between directional and diffuse light — belongs to the same question.
Zones, per-zone uniformity and the maintained-value rule: IBE-BIV guide, pages 10, 11 and 16. Glare series, class boundaries and the tabular-method warning: ZVEI / licht.de, Position paper UGR method – application and limits, October 2021, https://www.licht.de/fileadmin/Publications/ZVEI_Publications/2110_E_ZVEI_UGR_method.pdf — cylindrical range: https://www.cibsejournal.com/technical/work-light-balance-key-changes-to-workplace-lighting-guidance/
What changed in 2021
Two illuminance columns instead of one
The 2011 tables gave one maintained illuminance per activity. The 2021 tables give two: a required value, which is the minimum, and a modified value that takes the context characteristics of clause 5.3.3 into account. The modified value is not a ceiling — the Belgian guide states it cannot be interpreted as a maximum limit value.
Seven conditions decide whether you move. Where one or two apply, the guidance is one step up the standard’s illuminance ladder; more than two, two steps. CIBSE puts it in a line: “If there are one to two additional requirements, an increase of one level should be made – for example, from 500 lux to 750 lux.” The conditions are recognisable rather than exotic: tasks critical for safety or economic value, increased concentration, exceptional precision, observers with poorer vision such as older workers, unusually long observation times. Raising the task value raises the room with it — cylindrical, wall and ceiling values move up a step too.
Wall, ceiling and cylindrical requirements moved into the tables
These are not new requirements. The 2011 edition already carried general minima in its running text — ETAP’s dossier on that edition records walls above 50 lx and ceilings above 30 lx, tightened to 75 lx and 50 lx for enclosed rooms such as offices and classrooms. What 2021 changed is where they live and how specific they are: in the requirement tables, per activity. For ordinary office work the 2021 table asks 150 lx on the walls and 100 lx on the ceiling. Treat the older general minima as history, not as today’s target.
The rest of the revision
- Requirements set per work area rather than per room, with the quality criteria integrated into the tables.
- Glare requirements adjusted and better explained, with a new annex A for situations the standard method does not cover.
- A new chapter on lighting design based on CEN/TS 17165, and a completely revised section on flicker and stroboscopic effects.
- New annexes: B on non-visual effects, C with worked examples, D alongside new requirements for education, logistics, car manufacturing, maintenance, rail and retail.
- Daylight developed further with a reference to EN 17037, and a simplification for uniformity: points in a band next to the wall may be excluded from the calculation.
The two-column mechanism, the seven conditions and the list of changes: IBE-BIV guide, pages 8, 9-10 and 15-18. Two independent confirmations that the wall, ceiling and cylindrical requirements moved into the tables: https://www.cibsejournal.com/technical/work-light-balance-key-changes-to-workplace-lighting-guidance/ and https://www.fagerhult.com/knowledge/light-planning/en-12464-1/lighting-of-indoor-workplaces/standard-en-12464-1-in-brief/ — the 2011 wall and ceiling minima come from ETAP’s dossier on the 2011 edition and are shown here as 2011 values only.
Example: office lighting requirements
One room type, to make the columns concrete: the lighting levels EN 12464-1 asks for in an office. The standard covers dozens of other activity groups, and nothing below transfers to a workshop or a warehouse.
| Task or activity | Ēm required (lx) | Ēm modified (lx) | Uo | Ra | RUGL |
|---|---|---|---|---|---|
| Writing, typing, reading, data processing | 500 | 1000 | 0.6 | 80 | 19 |
| Filing, copying and similar | 300 | 500 | 0.4 | 80 | 19 |
| Technical drawing | 750 | not published | 0.7 | 80 | 16 |
| Conference and meeting rooms | 500 | not published | 0.6 | 80 | 19 |
| Reception desk | 300 | not published | 0.6 | 80 | 22 |
Sources. Rows one and two, modified column included, are reproduced from figure 6 of the IBE-BIV Guide pratique, which prints them with the credit “Source EN 12464-1”. Conference and meeting rooms comes from the published summary at https://www.techlumen.gr/en/guide/lighting-standards-guide/ — technical drawing and the reception desk from ETAP’s Dossier EN 12464-1, https://www.etaplighting.com/sites/default/files/uploads/Dossier%20EN%2012464-1_AT_EN_A4_lr.pdf. Read those last two rows with care: that dossier documents the 2011 edition, and the 2021 values for them are not published in any public source we could verify. Public sources also disagree on the reception uniformity — 0.4 circulates in secondary summaries, ETAP prints 0.6, and 0.6 is shown here. No public source we could check prints the modified column for the last three rows, so it is left unfilled rather than guessed. One rule belongs with row one: in small cellular offices the wall requirement applies to the front wall, and at least 75 lx may be accepted for the others. Verify against the published standard for your room type before you specify.
How a compliant lighting study is made
A compliant study is a set of checks, not a single number.
- Set the zones. Each task area gets its own reference surface, with its surrounding band and background around it.
- Put a calculation grid on each reference surface. The result is read off that grid, so the spacing belongs in the report.
- Fix the maintenance factor first. Ēm is a maintained value, so that factor decides how far above target a fresh installation starts; the same layout passes or fails on it.
- Check per zone against the values for that activity: Ēm, Uo, Ra and RUGL, plus the cylindrical, wall and ceiling values from the same row.
- Report per zone. A single pass or fail for a floor hides the zone that failed.
Glare is where reports most often overclaim. The tabular method places two observers mid-wall, looking horizontally at 1.2 m eye height, along and across the luminaires — no diagonal viewing direction exists in it — and applies to rectangular rooms between 2H and 12H, where H is the distance from eye level to the mounting plane. A per-point UGR maximum from calculation software is a different quantity: ZVEI states such a maximum is not comparable with the UGR limits.
Momik runs this in four steps. You draw or upload your zones, and each type is given the standard values that belong to it. You filter the catalog on your requirements, click Calculate — illuminance, uniformity, UGR and isolux per zone — and receive a standards-compliant PDF report with heat maps, a luminaire list and results zone by zone. Maintained illuminance, uniformity (Uo) and UGR are checked per zone against the standard values for that room type, so the compliance is readable instead of assumed.
Observer positions, eye height and the definition of H: IBE-BIV guide, pages 28-29. Room-dimension range and the warning on a calculated UGR maximum: ZVEI / licht.de, https://www.licht.de/fileadmin/Publications/ZVEI_Publications/2110_E_ZVEI_UGR_method.pdf
Where to get the official text
This page is a summary; only the published text is authoritative for the room you are designing. The standard is sold, not free, by the national standards bodies:
- Belgium — NBN EN 12464-1:2021, through NBN: https://www.nbn.be/en/buying-standards/how
- United Kingdom — BS EN 12464-1:2021: https://knowledge.bsigroup.com/products/light-and-lighting-lighting-of-work-places-indoor-work-places-2
- Germany — DIN EN 12464-1, edition 2021-11, also via resellers such as European Standards: https://www.en-standard.eu/din-en-12464-1-light-and-lighting-lighting-of-work-places-part-1-indoor-work-places/
- Netherlands — NEN-EN 12464-1:2021, article number 286866: https://www.nen.nl/nen-en-12464-1-2021-en-286866
Prices are left out on purpose: they differ per body and per edition, and they change.
Free to read, and the three documents most of this page rests on. IBE-BIV Guide pratique (French, reproduces the office requirement table with attribution): https://ibe-biv.be/wp-content/uploads/2023/11/IBE-BIV-NBN-EN-12464-1-2021-Guide-pratique-de-leclairage-des-lieux-de-travail-interieurs-adjust.pdf — CIBSE Journal on the 2021 changes: https://www.cibsejournal.com/technical/work-light-balance-key-changes-to-workplace-lighting-guidance/ — ZVEI / licht.de on what the UGR method can and cannot tell you: https://www.licht.de/fileadmin/Publications/ZVEI_Publications/2110_E_ZVEI_UGR_method.pdf. On whether a standard is binding, NBN’s own FAQ is the source: https://www.nbn.be/en/faq — all checked 17 September 2026.