EN 12464-1:2021 – Key Lighting Requirements for Indoor Work Places
Proper lighting in work places represents one of the most crucial factors that have an impact on comfort and efficiency in task performance. EN 12464-1:2021 set outs the requirements for lighting intensity and quality in indoor work places so as to ensure optimal working conditions. This article discusses the key principles of the standard and aspects of its implementation.
Importance of EN 12464-1:2021
Adopted by the European Committee for Standardisation (CEN) on 9 May 2021, EN 12464-1:2021 defines lighting requirements for indoor work places. Its key objective is to standardise relevant requirements to enhance visual comfort and performance, thereby improving workplace quality.
The standard sets out requirements that pertain to both lighting parameters (quantity and quality of light) and best practices for designing lighting systems including users’ visual and non-visual needs. While EN 12464-1:2021 is not a set of mandatory requirements relating to human safety or health, its guidelines can be applied in lighting system design. Dynamically developing technologies and innovative lighting design solutions used in lighting design make it possible to combine proper visual perception and compliance with workplace lighting requirements.
Lighting Assessment Criteria in Work Places
EN 12464-1:2021 challenges lighting designers to meet the key needs of workers. One of the most significant aspects is visual comfort, which has a direct bearing on well-being, productivity, and efficiency. Another key factor is visual performance, with an environment where tasks can be performed over long periods, even under challenging conditions. Workplace lighting also plays a role in workers’ safety in task performance, boosting a sense of confidence and inspiring peace and psychological balance among the staff.
To meet the lighting installation requirements, a number of criteria are assessed: In the standard under consideration, these are:
- maintained illuminance (E̅m) and its overall uniformity (Uo),
- Unified Glare Rating (RUGL),
- luminance distribution,
- interior lighting and light directionality,
- light colour appearance and colour rendering (Ra),
- flicker,
- light variability.
The article sets out the requirements for illuminance.
Illuminance
The primary parameter assessed in workplace lighting surveys is illuminance, measured in lux [lx] or foot-candles [fc], with EN 12464-1:2021 using only lux. Measurements are taken with illuminance meters, known as lux meters. The assessment covers the following areas:
- task and activity area,
- immediate surroundings,
- background area,
- walls,
- ceilings,
- objects within the space.
EN 12464-1 establishes minimum maintained illuminance values (Ēm) to ensure optimal conditions for visual tasks in work places. These values consider normal visual conditions, including visual ergonomics, task requirements, visual comfort, workplace safety, and economic factors.
Context modifiers
The latest edition of the standard allows for context modifiers, applicable in justified cases. Designers of lighting should provide for illuminance levels higher than the minimum to provide an operational reserve for compliance with stricter requirements. Context modifiers are categorised as increasing or decrease maintained illuminance values. It is recommended not to increase the requirements by more than two degrees for three or more modifiers occurring, or by one degree where there are two or one modifiers. A decrease can be made by a maximum of one degree. The factors that increase requirements include the following:
- critical visual tasks;
- costly error corrections;
- tasks requiring enhanced concentration, productivity, and precision;
- small object sizes related to the task at hand;
- long task durations;
- limited or no daylight;
- workers with reduced visual abilities (age-related retina degeneration0;
- disability.
Context modifiers affecting decisions to decrease the minimum maintained illuminance values specified in the standard relate to the following:
- tasks with a high degree of contrast and large object sizes related to the task at hand;
- very short task durations.
Illuminance in on the task or activity area
The reference plane for the task or activity area can be horizontal, vertical or inclined. During measurements, it is necessary to document the task area location and size. It goes without saying that these details are often not yet known when designing a lighting system. When this is the case, two approaches are acceptable in accordance with the standard:
- treating the entire area as a task area, so as to make provisions for all scenarios when creating a workplace environment;
- providing uniform illumination across the area, as required by the designer, with adjustments in the arrangement of luminaires once the task area is defined.
In both cases, zone lighting is recommended to make it easier to provide appropriate lighting in the future and optimise the cost of any upgrades.
If the type of task that will be performance in the work place is unknown at the time lighting is designed, designers should assume the most likely scenario and define requirements accordingly. Sometimes activities of different nature and type are performed in the task area. If this is the case, it is necessary to adopt criteria to satisfy the requirements for all types of tasks and activities, i.e. the most restrictive ones.
Illuminance on the immediate surrounding area
The immediate surrounding area refers to the task or activity area. According to EN 12464-1:2021, it should include a strip of at least 0.5 m around the task area. The size and location of this area should be determined and specified in the documentation. The primary assessment involves measuring the illuminance, which, according to the established criteria, should be equal to or lower than the maintained illuminance required for the task area. This value is usually one degree lower than in the task area, although exceptions may occur in certain situations.
During the design phase, it is also crucial to ensure an appropriate luminance distribution and to prevent significant spatial variability in illuminance.
Illuminance on the background area
The background area is closely related to the immediate surrounding area and, according to the discussed standard, should be a strip of at least 3 meters wide around the immediate surrounding area. For smaller rooms, instead of 3 meters, it is acceptable to define the area up to the boundaries of the space, such as walls. The background area is a plane adjacent to the immediate surrounding area at floor level. Here, it is also required to specify the size and location and include this in the documentation. The primary assessment of the background area involves measuring the illuminance, which, according to the criteria established in the standard, is defined in relation to the requirements in the immediate surrounding area and amounts to one-third of that value. The relationships of the required illuminance values in all three areas are given in Table 1.
| Task or activity area illuminance [lx] | Immediate surrounding area illuminance [lx] | Background area illuminance [lx] |
|---|---|---|
| ≤ 150 | the same as in the task area | 1/3 of the value in the immediate surrounding area |
| 200 | 150 | 50 |
| 300 | 200 | 66,(66) |
| 500 | 300 | 100 |
| ≥ 750 | 500 | 166,(66) |
Illuminance uniformity
EN 12464-1:2021 lays down not only the illuminance requirements for work and activity areas, but also the requirement to maintain adequate uniformity of lighting. Lighting uniformity is defined as the ratio of the minimum to the average illuminance over a given area. Higher uniformity helps to ensure safety, efficiency, and comfort at work by eliminating abrupt changes in brightness that can cause eye strain and reduce productivity. Minimum uniformity values in the task and activity area are shown in the tables of the standard. For immediate surrounding areas and background areas, these values remain constant, irrespective of the type of activity:
- the immediate surrounding area: the minimum uniformity value is 0.40;
- the background area: the minimum uniformity value is 0.10.
It is important to note that uniformity requirements apply exclusively to electric lighting. In rooms with access to natural daylight, lighting conditions change depending on the weather, time of day and season, making the uniformity criterion inapplicable in such cases.
Cylindrical illuminance
In addition to ensuring the required illuminance on activity surfaces, EN 12464-1 recommends lighting the space in which people stay (move and work). This parameter is called cylindrical illuminance. It refers to the illuminance at a given point in space for a full rotation of the vertical plane around the axis containing that point. The following figure can be used to illustrate this attribute.
Figure 1 Cylindrical illuminance
Maintaining this parameter at the proper level ensures good visual communication and recognition of objects and their shapes in a three-dimensional space. The required values for specific task or activity areas are provided in the tables of the standard. The uniformity of cylindrical illuminance should be at least 0.10. The average maintained cylindrical illuminance can be calculated using four orthogonal vertical illuminance values. The height at which cylindrical illuminance is measured and/or calculated depends on the nature of the task:
- for a seated position: 1.20 m above the floor level;
- for a seated position: 1.60 m above the floor level.
When designing lighting, a balance must be maintained between overly directional lighting, which can create shadows that are too harsh, and overly diffuse lighting, which may reduce the modelling effect and create a monotonous environment, thus reducing concentration during tasks.
When designing interior lighting, the surrounding spaces of the workstation must also be considered, including wall surface illuminance (E̅m,wall) and ceiling illuminance (E̅m,ceiling). This factors determine whether stimuli such as room brightness are properly perceived. It is important to note that if the required illuminance level increases, the cylindrical illuminance must be raised accordingly.
Maintenance factor
The maintenance factor (fm) must be considered when designing the lighting installation. This factor determines the oversizing of the required basic lighting levels – maintained illuminance. Factors that influence the maintenance factor are the type of lighting fixtures, the environment in which the fixtures are used (dust levels, air pollutants, chemicals that may degrade fixtures, the duration of uninterrupted fixture operation, decline of luminous flux over the fixture or light source’s lifespan). The designer is responsible for defining a maintenance plan for the task or activity area, based on the guidelines in ISO/CIE TS 22012. This includes the frequency of light source replacement or fixture replacement where the source cannot be replaced separately and the frequency of fixture and room cleaning The designer also determines which type of lighting equipment should be used to align with the planned maintenance factor. The maintenance factor is also related to the energy efficiency of the lighting system. Properly planning maintenance can help reduce costs associated with maintaining the required lighting levels. The formula for calculating the required initial illuminance, considering the maintenance factor, is as follows:
(E̅i) = (E̅m)/fm
with:
E̅i – initial illumination including the maintenance factor
E̅m – maintained illuminance
fm – maintenance factor
For example, if the required maintained illuminance for food preparation and baking areas in bakeries is 300 lx, and the maintenance factor is set at 0.8, the initial illuminance value at the time of installation should be 300 lx / 0.8 = 375 lx.
Verification procedure
According to the requirements of EN 12464-1:2021, after installing the lighting system, it is necessary to conduct a series of inspections and tests so as to verify compliance with the design specifications. This article focuses on illuminance parameters; accordingly, the verification process involves the following:
- measurement points must correspond to those specified in the design or follow a measurement grid;
- tests must be conducted according to criteria applicable to the respective surfaces;
- repeated periodic measurements should be taken at the same points;
- verification for specific areas should include the perpendicular component on the task surface.
- measurement instruments must have calibration certificates.
- light sources and fixtures must comply with published photometric data;
- the reflectance coefficients etc. adopted in the design must match real conditions;
- the average maintained illuminance and uniformity, calculated on the basis of the measured values, must not be lower than the requirements specified in the standard’s tables;
- the maintenance plan should be implemented according to the assumptions made by the designer.
Bibliography
EN 12464-1:2021. Light and lighting. Lighting of work places – Part 1: Indoor work places.
Author:
Adam Szczepanik, Sonel S.A.
