Learn what it is and how to do the lighting calculation!

The lighting calculation can help or hinder the visibility of a corporate environment. It is very important to determine the correct amount of LED devices for efficient lighting of a specific location.

With this calculation, it is possible to discover if the qualitative and quantitative aspects of current regulations are being met. In this post, we will present information about the lighting calculation and talk about the level of illuminance for each environment.

In addition, we will explain what it is, what are the main variables to be considered and how this calculation is done. Here, you will find details about technical standards, methods used, natural light utilization, among others.

Would you like to know more about the lighting calculation? Follow the reading of this article!

Learn what the lighting calculation is

The planning of lighting projects is carried out through lighting calculations that include all environmental factors and conditions. Therefore, the lighting calculation is a tool used by specialized professionals to discover which equipment or light sources are necessary for the adequate illumination of an area.

Understand the main variables of the lighting calculation

Performing the lighting calculation is essential to ensure the correct determination of lighting points. The variables analyzed by designers are diverse, such as the balance between artificial light and natural light and the combination of both.

Other factors evaluated are the most suitable LED devices, the distance between light sources and the dimensions of physical structures. In the point-to-point method, the specialist evaluates luminous intensities through small punctual luminaires and defined light beams.

In this case, the luminous intensity is vertically cast on the location or physical dimension. In the lumens method, the unique numerical result of luminosity is obtained based on the characteristics of the environment and the selected equipment.

Discover how the lighting calculation is done

Initially, the average lighting level is identified, according to the guidelines of NBR ISO/CIE 8995-1:2013, which defines the essential requirements for internal work areas. The value is verified with the specific environment’s activity in mind.

Then, the calculation of the local index that observes the physical structure dimensions in meters must be performed. After that, the definition of the utilization factor provided by the LED luminaire manufacturer is made.

A table comes with items to cross-reference the reflectance indices with the room index. The next step is to define the maintenance or depreciation factor that is related to the flow emitted by the device in its initial period and after the review period.

The light directed to the area can cause glare that needs to be delimited. Therefore, the level of glare also needs to be considered. The luminous distribution curve and the positioning of the items cannot impair the activities of the employees. Consequently, the number of LED luminaires is determined considering various factors, such as:

• Average illuminance;
• Area of the environment;
• Number of LED devices;
• Luminous flux;
• Utilization and maintenance factor;
• Distribution of LED luminaires;
• Ballast luminous flux factor.

Lighting systems are designed according to the factor of luminous losses, the activity performed, the type of environment, and the models of LED luminaires or reflectors used. These parameters are useful because over time, equipment use reduces the luminous flux due to wear and dust accumulation.

Once the necessary quantity of items to achieve the ideal level of brightness is determined, a balanced distribution will be made in the environment with distances between devices and between them and the walls. Luminaires can be added if the calculation is incompatible with the ideal distribution.

Let’s imagine a practical example of this calculation in an environment with basic activities during a few hours.

If the ABNT (Brazilian Association of Technical Standards) states that 200 lux is necessary for carrying out tasks, the formula “X LM / 5 square meters = 200” is used. In this case, we have the following: 200 x 5 = 1,000 lumens. With two luminaires emitting 500 lumens each, the environment will be perfectly illuminated.

Understand technical standards

The standards considered in the lighting calculation are focused on work safety, health, and occupational hygiene. Regulatory Standard NR 17 brings rules related to ergonomics and deals with efficient performance, safety, and comfort issues of users exposed to lighting.

Occupational Hygiene Standard NHO 11/2018 highlights the evaluation procedures and criteria for lighting levels, providing qualitative and quantitative parameters of lighting.

Finally, the NBR ISO/CIE 8995-1:2013, already mentioned, and INMETRO (National Institute of Metrology, Quality, and Technology) Ordinance No. 20, which imposes conformity requirements for devices, are observed.

Check how the lighting calculation affects the use of natural light

The lighting calculation is carried out taking into account the natural light of the environment. The brightness that enters the rooms through windows, doors, or ceiling directly influences the lighting design. Therefore, designers calculate how much natural light is available in the environment to generate maximum energy savings for users.

Artificial light is added to natural light and the points are combined through evaluation. Current technologies work with management software, drivers, sensors, and automation, making LED lighting even more intelligent. Presence sensors activate the luminaires to turn on and off automatically, whenever necessary.

If you still have doubts about the lighting calculation, know that there are specialized software programs for it. They can help provide greater accuracy to your project, which will be designed and executed by specialized professionals. You can partner with a company that offers LED lighting solutions!

Now that you are convinced that SX Lighting will provide you with the best lighting, click here and request a free lighting design project with our specialists.