Calculation of illuminance is the basic calculation for lighting planning and design.

Any lighting design should start with defining the intended use of the building and the particular room (warehouse, training class, gym, sales hall, office, living room etc.) or the type of the outdoor area (car park, street, territory or facade of a buiding, public road ec.).

Based on this and the standard requirements for indoor, outdoor and emergency lighting, the illuminance, the required technical parameters of light fixtures are determined. It is not possible to make correct lighitng calculations without knowing the illuminance requirements.

Illuminance calculation is a set of works including a light fixture selection and its efficient placement, calculation of the power consuption of the lighting system, and management of the future maintenance of the system. Illuminance can be defined as the ratio of the light flow covering a lighted surface to the area of this surface.

The calculations can be manual or automatic. Today, there are many types of illuminance calculation software that considerably reduce that calculation time and allow for the visualisation of the result (tables, schemes, images in light or pseudo-color images, location of the light fixtures).

We use Dialux professional software in our work, which is able to calculate not only the illuminance of indoor rooms, but also the illuminance of the outdoor building facades, parks, streets and car parks. Dialux 4.13 is the best to calculate the emergency lighting, while Dialux Evo is more convenient for creating several variants of the light scenarios and chose the optimal one. It is especially convenient where the lighting patterns need control depending on the time or situation.  In order to achieve the required result, the software allows for playing with the light fixture types, allocation and the light intensity. The programm makes calculations and offers result following every combination of the fixtures. The result visualise the actual light distribution over the surfaces.

Unlike an ordinary 3D visualistion made by designers, the professional illuminance calculation presents the actual light distribution and the quality of the room's illuminance. The professional software determines the right point to install the light fixture and its type.

Many factors shape the final result and therefore shall be taken into account. These include but are not limited to the following: reflection factor, energy efficiently, maintenance factor, colour rendering, glare rating etc.. It is also important to take into account any furniture/equipment/shelves int he rooms, as they may significantly affect the reflecting ration of the walls and therefore reduce the illuminance. When calculating the illuminance for a empty room, the risk is that when the luminaries are installed, the illuminance in the room is not even or the workplaces have less light than their surroundings.

It is also worth mentioning that replacing the design light fixtures for their analogues may cause unsatisfactory results if only the power in watts (W) and luminous flux in lumens (lm) of the subsitute fixtures are used without additional calculation of illuminance. Every manufacturer uses its own LED modules, optical parts, reflectors and diffusors, determining the luminous flux distribution of a particular light fixture and eventually the total lighting scenario. That is why the technical criteria of the design specification are not enough when replacing luminaries and additional lighting calculations is recommended.

If You are interested in making a professional lighting calculation and/or getting lighting equipment, please contact us by e-mail and we will gladly help You with the organisation of lighting at Your site.