• Karim El Faramawy

Workplace 101: And then… there was light!

Welcome back to another episode of Workplace 101, where I will be discussing different aspects of workplaces, and how their architecture and design can have a profound effect on those using the spaces.

In my previous article, I took a look at the different workplace plans and layouts and how each of them affected the activities going on there. In this second article we will discuss one of the most influential—and technically complicated—elements of the workplace: Lighting.

The importance of light emanates from 2 basic facts: it has a significant effect on human health and wellbeing, and it is a mandatory need for almost all activities taking place inside the office. Discussions around lighting might seem simple (just add a few light bulbs here and that’s it), in reality the design of lighting is one of the most technically complicated tasks in workplace design.

That being said, let’s go over a few rules of thumb that you can use to enhance your office lighting quality to achieve 3 major goals: visual comfort, visual performance, and visual safety.

First, let’s start with natural light

There are 3 types of natural light: direct sunlight, daylight, and bounced light.

Direct sunlight is… just that: light coming directly from the sun. It is important in that it is undesirable for indoor lighting and we usually want to avoid it and block it out.

Daylight -aka skylight -is the general light present during the daytime, even if the sun is nowhere in sight; it is sunlight reflected off the sky. This is the type of natural light that we use for daytime office illumination.

Bounced light is light from the previous two sources reflected off surfaces. It has no bearing on illumination, but plays a role in the perception of color.

There are many different factors that contribute to the effect of daylight on indoor lighting. Unfortunately, most of them are not easily controllable, like: building orientation and geometry, geographical region, weather conditions, heights of surrounding buildings and the materials and colors used in their finishing.

If you’ve been blessed with an abundance natural daylight without direct sunlight, then this will be one of the best things to happen to your workplace. If you don’t, then you will probably need to use blinders and tinted glass to reduce direct sunlight and heat it causes, and resort to artificial lighting to boost your indoor illumination.

An example for using daylight in workplace illumination, from Mrsool Workplace Project

A common misconception…

Many people think that any wide view provides desirable daylight. In reality, this is totally dependent on the building’s orientation and the direction of the view. My previous article gives a bit more on this.

The other type of lighting: artificial light

Most offices rely on artificial lighting for their indoor illumination. The spectrum of types, technologies, and colors in artificial lighting is mind-bogglingly wide, but only a handful of these options is suitable in workplace environments.

In general, the needs in illumination intensity and quality can differ from one person to another depending on many factors like age, gender, and eyesight. However, the vast majority of studies show that the closer the light source mimics daylight, the healthier and more convenient it is for doing work, as it makes people more alert and better able to focus.

How do we measure light?

This next part is a bit of hairy technical terms, so if you hated physics in school, you can skip ahead.

Light can be measured using several scales. Relevant to our discussion are CCT, CRI, luminous power, and luminous power per area.

CCT stands for Correlated Color Temperature, and this is a tricky concept but we’ve all seen its applications somewhere. If we heat a black steel bar, it starts to change color from black to red, then as we increase the temperature it turns yellow, then white, until finally it reaches a blinding blue at extremely high temperatures. This—in very simple terms—is the physical concept behind CCT: different colored light is emitted at different temperatures, from a orange at lower temperatures to blue at the highest. Hence, the light color is defined by temperature.

CCT is measured in Kelvins (K) and the two most common grades of CCT available in the Egyptian market are 2700K and 6000K, but it’s very rare to find anything in between.

source: wikipedia

CRI is the Color Rendering Index, which indicates how distinct the different colors of objects will be under that light. So if you walk into a room illuminated with a low CRI light, a green and blue object could appear very similar so you can probably only make out 3 or 4 distinct colors; the higher the CRI, the more you can differentiate between colors. The highest CRI is provided by daylight (which has a maximum of 100, no units).

Luminous power is the amount of visible light emitted from a source and is measured in lumens (lm). It compares the amount of light given off to how many candles would give that same amount. A regular wax candle giving light in all directions gives off about 12.5 lumens. Luminous power per area measures how many lumens are present in one meter and is measured in lux (lx), where 1 lux is 1 lumen in 1 square meter.

So how can we mimic daylight?

Based on the above, in order to mimic daylight, you’ll need to illuminate your office with light bulbs that have a CCT of 4000-6000K and a CRI above 80.

However, bear in mind that the sun tends to set every day! Our bodies are wired to start getting ready to sleep as soon as the sun goes down. If your eyes get daylight (which is rich in blue light) in the evening, your body responds to that with continued alertness and it can mess with your sleep cycles. Warmer orange light in the evening is a better idea to preserve your ability to sleep soundly.

A Mini-Guide to Illuminating your Office

Different spaces need different amounts of light depending on the activity taking place within. If you remember from above (or if you happened to skip that part!), the amount of light needed to illuminate a specific area is measured in lux (lx; which is 1 lumen/meter2).

1- Measure your room area to know the amount of lumens you know to properly illuminate it.

2- Task areas in a workplace need about 500 lux. In other words, every square meter needs 500 lumens. Background areas should get around 300 lux, and corridors, 100 lux.

3- It is very important to have your light bulb 2.4 meters, minimum, above the finished floor. Any lower could cause eye strain.

4- Light sources should be distributed on a grid in the ceiling to ensure an even light diffusion in the office. This is a rule of thumb, but might not always be optimum in all cases. Some instances require an indoor lighting simulation.

5- Get the number of bulbs/panels equivalent to the amount of lumens you need and disturb them on a grid. ( a distance of 50 cm from the wall is ignored)

6- Before buying your light bulbs, check the specs to make sure the CCT is 4500-6000K & the CRI is above 80.

7- DON’T use a light bulb with CCT of 2700K. It is the absolute worst for workplaces, no matter who says otherwise.

So, to wrap it all up

It might seem like a no-brainer that your office needs light.

However, you’ll find that “Lucifer” (whose name actually means “bearer of light”) is in the details.

Sometimes it needs rigorous calculations and thorough knowledge of exceptions to make the best decisions to provide the best light for workers health, wellbeing, and productivity, while at the same time cutting the costs of electricity to the bare minimum.

Do you face any challenges in your current workplace lighting? Let me know in the comments.

Have a happy and productive workplace, and until we meet again!

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