Workplace lighting

Minimum levels and conditions of Royal Decree 486/1997

Annex IV of Royal Decree 486/1997 establishes that the lighting of each area or part of a workplace must be adapted to the characteristics of the activity, taking into account the safety and health risks dependent on visibility conditions and the visual demands of the tasks. Whenever possible, workplaces shall have natural lighting, supplemented by artificial lighting when the former does not guarantee adequate visibility conditions, and general artificial lighting shall be used preferentially, supplemented by localized lighting when high levels are required in specific areas.

The minimum illumination levels set are 100 lux in areas where tasks with low visual demands are performed, 200 lux for moderate demands, 500 lux for high demands, and 1,000 lux for very high demands; 50 lux in areas or premises of occasional use and 100 lux in those of regular use; and 25 lux in circulation routes of occasional use and 50 lux in those of regular use, measured at the height of the task or, in circulation routes, at ground level. These levels must be doubled when there are appreciable risks of falls, collisions, or other accidents, or when a visual perception error could pose a danger, or when the contrast between the object and the background is very weak.

The standard also requires that the distribution of lighting levels be as uniform as possible, that adequate luminance levels and contrasts be maintained between the task and its surroundings, that direct glare from sunlight or high-luminance artificial sources and indirect glare from reflective surfaces be avoided, that systems that impair the perception of contrast, depth, or distance not be used, and that areas where a lighting failure poses a risk be equipped with emergency, evacuation, and safety lighting. The INSST technical guide on workplaces and NTP 211 further develop these criteria.

Lighting quality factors

• Illumination level. Illuminance maintained in the task according to UNE-EN 12464-1 (for example, 500 lux for office work with reading and writing, 750 or more for precision tasks), with the legal minimums of Royal Decree 486/1997 as the floor.
• Uniformity. Relationship between the minimum and average illuminance in the task area and its immediate surroundings, avoiding dark areas and sharp contrasts.
• Glare. Direct (light sources or windows in the field of vision) or reflected (glossy surfaces, screens); it is controlled with shielding, orientation of luminaires, blinds, matte finishes and arrangement of workstations.
• Luminance and contrast. Balance between the luminance of the task, the immediate environment and the background to avoid continuous visual adaptations and fatigue.
• Color rendering and color temperature. Color rendering index appropriate for the task (essential in quality control, healthcare, graphic arts) and color temperature consistent with the lighting level and the use of the space.
• Flickering and stroboscopic effect. Electronic sources and equipment that prevent perceptible flickering and the stroboscopic effect on rotating machinery, which can make moving elements appear stationary.
• Natural lighting. Taking advantage of daylight with glare and overheating control, and complemented with adjustable artificial light.
• Maintenance. Cleaning of light fixtures and surfaces, replacement of lamps and monitoring of the maintenance factor to maintain design levels.

Specific situations

• Display screens. Royal Decree 488/1997 requires that general and localized lighting guarantee adequate levels and contrasts between the screen and the environment, and that reflections and glare on the screen are avoided by the arrangement of the workstation with respect to windows and light fixtures.
• Precision tasks. Complementary localized lighting with glare and shadow control, and high levels according to UNE-EN 12464-1.
• Industry and workshops. Lighting of machinery and risk areas, prevention of the stroboscopic effect, doubling of levels in areas with risk of accidents and emergency lighting.
• Warehouses and logistics. Adequate levels in aisles, docks and picking areas, uniformity in high shelving and lighting transition between interior and exterior.
• Night and outdoor work. Lighting of roads, access points and outdoor work areas according to the activity, with attention to safety and fatigue.
• People with special needs. Adaptation of levels and contrasts for older workers or those with visual limitations, in accordance with the principle of adapting the work to the person.

Organizational application: how to manage lighting in the company

1. Classify the positions and areas according to visual requirements and risks associated with visibility, and determine the required lighting levels in accordance with Royal Decree 486/1997 and UNE-EN 12464-1.
2. Measure the illuminance in the task and in the traffic routes with a calibrated lux meter, under representative conditions and considering natural light, and evaluate uniformity, glare and reflections.
3. Correct the deficiencies by redesigning the installation (number, type and arrangement of luminaires, localized lighting), controlling glare (shielding, blinds, finishes) and relocating workstations with respect to windows and luminaires.
4. Verify the workstations with display screens in accordance with Royal Decree 488/1997 and its technical guide.
5. Ensure emergency and evacuation lighting in places where a failure poses a risk, with periodic checks.
6. Establish the maintenance program for the lighting installation: cleaning, lamp replacement, and level checks.
7. Consult with workers, collect complaints of eye strain or glare, and review lighting when layout, tasks, or equipment changes.

Preventive management software allows you to record lighting measurements by workstation and zone, compare them with required levels, plan corrective actions and maintenance of the installation, and document reviews of workstations with screens.

Limits and common mistakes

1. Meeting the minimum legal level without considering the actual demands of the task or the duplication of levels in areas with a risk of accident.
2. Placing workstations with screens in front of windows or under unshielded lights, with reflections and glare.
3. Measure at a single point or without considering the variation of natural light throughout the day.
4. Neglecting maintenance: dirty light fixtures, burnt-out lamps, and levels far below design specifications.
5. Ignore the stroboscopic effect in areas with rotating machinery or the flickering of deteriorated equipment.
6. Forgetting emergency and evacuation lighting or not checking it periodically.

The detailed conditions are set out in Annex IV of Royal Decree 486/1997, in Royal Decree 488/1997 and in the INSST technical guides; this sheet is for informational purposes.

Regulatory and reference framework

• Royal Decree 486/1997, of April 14. Workplaces ; Annex IV on lighting: minimum levels, uniformity, glare and emergency lighting.
• Royal Decree 488/1997, of April 14. Work with equipment including display screens; lighting, reflections and glare.
• Technical guide for the assessment and prevention of risks related to the use of workplaces (INSST) . Criteria for the application of Annex IV on lighting.
• Technical guide for the assessment and prevention of risks related to the use of display screen equipment (INSST) . Lighting and layout of workstations with screens.
• NTP 211: Lighting of workplaces (INSST) . Concepts, magnitudes and evaluation criteria for lighting.

The UNE-EN 12464-1 standard establishes the lighting requirements for indoor workplaces and the UNE-EN 12464-2 those for outdoor workplaces; the UNE-EN 1838 regulates emergency lighting and the Technical Building Code the requirements in buildings.