Workplace lighting — lux levels and glare per NEN-EN 12464-1

The 560-emergency lighting guide and the EMF exposure guide both cover mandatory workplace requirements that do not follow directly from NEN 1010 itself, but from adjacent occupational-health regulation. NEN-EN 12464-1 is one such standard: the requirement for everyday workplace lighting during normal operation — an entirely different subject from the photometric requirements for escape lighting during a mains failure (see the 560 guide, based on NEN-EN 1838, with its own, much lower lux values for a different purpose).

Maintained illuminance (Em) per task type

NEN-EN 12464-1 specifies a minimum maintained illuminance (Em, the average illuminance over the service life of the installation, i.e. after light-source ageing/luminaire soiling) per task type, for example:

Office desk/meeting room: typically around 500 lux.
Corridor/circulation area: a considerably lower value, typically in the order of 100-200 lux.
Fine precision work (for example technical drawing): considerably higher, typically 750 lux or more.

Note: the exact Em value per specific task/space is worked out in the standard itself in an extensive per-activity table — this article gives indicative orders of magnitude, not an exhaustive table for every conceivable workplace.

Glare (UGR), colour rendering (Ra) and uniformity

Besides the lux value, the standard also sets requirements on the quality of the lighting:

UGR (Unified Glare Rating): a measure of glare from luminaires in the field of view — for office/screen-based work typically a limit of UGR ≤ 19; for rougher industrial work a higher (less strict) limit may apply.
Ra (colour rendering index): typically at least Ra ≥ 80 for most workplaces.
Uniformity (U0): the ratio between the lowest and the average illuminance on the task area, typically at least 0.6.

Measurement plane

For desk work, measurement is taken at task-area height (typically around 0.75 m above the floor, i.e. desk height); for corridors and circulation areas, measurement is typically taken at floor level. Confusing these two measurement planes gives a systematically incorrect (often too low) reading at office desks.

Practical relevance

During an occupational-health inspection or a complaint about insufficient workplace lighting, the first step is to establish which task type applies (desk work, precision work, circulation area) — the required Em value differs considerably between these, and a measurement not taken at the correct plane and for the correct task type gives an unreliable conclusion.

Common mistakes

Confusing the lux requirements of NEN-EN 12464-1 (workplace lighting) with those of NEN-EN 1838 (escape lighting) — two entirely different standards with a different purpose and very different values; see also the 560 guide.
Measuring at floor level for a desk workplace instead of at task-area height — gives a systematically deviating (often too low) reading relative to where the actual work takes place.
Only checking the lux value and ignoring the UGR glare requirement — a space can technically meet the lux requirement while glare from poorly shielded luminaires still impairs visibility of the work.