Persgebied

What are the aspects to consider to design effective lighting for school environments?

Federica Lucifora, professional lighting designer, explains practical rules to be taken into consideration in order to create correct lighting in schools.

Within a school we can identify a varied typology of environments: from classrooms (home-base) to relaxation spaces, from laboratories to connective spaces, from ateliers to the library. Lessons take place by moving to the various environments in which the activities carried out require, for the vast majority of the time, a substantial visual commitment: from simple reading and writing on paper or blackboards to watching movies on screens and projectors, from small manual jobs to technical drawing.

This visual commitment must never turn into an effort for the eyes of the users: at the base of each intervention there must be a lighting project capable of enhancing the spaces according to the function they are intended for, thus defining specific requirements and interventions.

The recommended average lighting levels are those indicated by the UNI 12464-1 standard; indicatively, the following values can be recommended:

In addition to the regulatory indications, we must not forget the need to meet the requirements of the minimum environmental criteria (CAM) prescribed by law. In particular:

Color Rendering Index (CRI - Color Rendering Index) not less than 90
Control of the relationship between natural and artificial light through management systems (the lighting devices must be connected to a system that allows dimming and regulation based on daylight)
Luminous efficiency> 80 lm / W

On the basis of these regulatory and legislative constraints we can therefore assert that the keywords in the design of school environments can be summarized as follows:

visual comfort;
energy saving;
maintenance interventions reduced to a minimum;
use of advanced technologies, but at the same time easy to use;
psycho-physical well-being of the users of the environments.

Speaking of visual comfort, in addition to average illuminance, we must pay close attention to glare as the choice of unsuitable luminaires could excessively tire users. The parameter that takes this aspect into account is the UGR (Unified Glare Rating - unified glare index). In reality, the UGR is a verification factor dependent on numerous environmental variables and therefore not only on the photometric and constructive characteristics of a lighting body; however, since many variables are not predictable in the design phase, it is always advisable to use lighting fixtures equipped with specific luminance control optics that guarantee compliance with the UGR regulatory values from all possible points of observation.

To minimize energy consumption, the development of the lighting project will include a system consisting of dimmable lighting devices automatically controlled by sensors that detect both the natural brightness present (consequently adjusting the luminous flux of the light sources) and the presence of people (after a predetermined period in which there is no movement, the appliances are automatically switched off). It should be remembered, however, that it is always necessary to guarantee the possibility of manually adjusting the luminous flux of the lighting devices if, in the case of particular activities, the normally expected flux is not suitable (for example during the projection of films on screens).

The presence detectors installed in the classrooms must be of the type suitable for 'micro-movements' as the traditional type detectors may not recognize users who are stationed seated in the desks.

It is important to underline how much automatic dimming allows to reduce electricity consumption for lighting: this saving can in fact be estimated at around 30%.

The graph below highlights, on a monthly basis:

in bordeaux, the energy consumption that would occur with classroom and studio luminaires without dimming
in purple, the actual energy consumption obtained by dimming the luminaires in classrooms and ateliers

A separate note deserves specific environments such as gyms and canteens.

If the gyms are also used for competitive purposes (volleyball, basketball, etc.) it will be necessary to refer to the specific indications of the CONI legislation; if, on the other hand, the gyms are used only for educational purposes, it is sufficient to satisfy the requirements set out in the initial table which contains the UNI 12464-1 requirements. Proper lighting design for these environments, however, must consider, in addition to the lighting parameters as such, the management / use of the system. In particular:

installation of lighting devices in positions that are easily accessible for maintenance, especially if located in high-rise environments;
installation of the lighting fixtures in positions protected from impacts related to soccer balls or alternatively choose protected fixtures or provide specific protection grids;
installation of the lighting devices in a 'decentralized' position with respect to the playing field so as not to dazzle those who look at the ball 'arriving' from above;
If the gyms are also used for competitive purposes, provide for the creation, through home automation applications, of different usage scenarios, for example match, training, educational use, cleaning, etc. in order to guarantee the correct level of illumination for each type of use.

As for the canteen areas, it is important to define whether these only involve the consumption of food or even the preparation.

In the first case it is usually traditional environments without the need for particular attention; in the second case, since there is also a kitchen room, it will be necessary to provide lighting devices that have a suitable IP rating that guarantees good waterproofing from liquids and food cooking vapors.

Emergency lighting

Last but not least, in addition to the artificial lighting of the rooms, a safety lighting system must be provided which must comply with the requirements of the UNI 1838 standard and the mandatory provisions on fire prevention; the system can be either centralized or with autonomous devices, with a minimum autonomy of 1 hour.

Along escape routes longer than 20 m, if the system is centralized, the lighting devices must be divided into at least two separate circuits; the UPS used as a safety source must comply not only with the product standard but also with the CEI EN 50171 standard.

The illumination along the escape routes and the emergency exits, measured at 1 m from the floor, must not be less than 5 lux, apart from schools with the presence of people less than 100 for which the general rules of referred to in the UNI 1838 standard.