Shedding Light on Lighting Levels: From Lumens to Foot Candles

August 28, 2023 by Brett Pauls

When we sit down at our desks, we often take the lighting for granted. Yet, the right amount of light can significantly impact our productivity and comfort. To understand this better, we need to explore the journey of light from its source to our workspace and the key metrics involved – lumens and foot candles.

The Beginning: Lumens and Light Sources

Light starts its journey at the source, which is usually a lamp or light fixture. The brightness of this initial light output is measured in lumens. Lumens tell us how much light is being emitted by the source. The more lumens, the brighter the light.

or instance, think about the fluorescent tubes in your office's ceiling. These tubes emit a certain number of lumens, determining the total light output in the room. But, here's where it gets interesting: not all of these lumens end up where we want them.

The Middle: The Journey of Light

Imagine you're at your desk, and the light fixtures above you are fluorescent tubes. These tubes emit light in all directions around the tube. However, for that light to reach your desk, it has to overcome some obstacles.

First, a significant portion of the emitted light has to bounce off the top of the fixture itself. This is because light, just like a ball bouncing off a wall, can reflect in different directions. Some of it goes directly downwards, but much of it initially goes up towards the ceiling.

The Destination: Foot Candles on Your Desk

Now, let's talk about what you actually experience on your desk - foot candles. Foot candles are a measurement of the amount of light that reaches a specific area, typically one square foot. So, when you're working, you're interested in how many foot candles of light are illuminating your desk.

To put it simply, foot candles tell you how bright your workspace is. The more foot candles, the brighter your desk will be. This is crucial because the right amount of light can reduce eye strain, improve concentration, and enhance the overall work environment.

The Balance of Lighting

To optimize your workspace, it's not just about having the brightest bulbs. It's about achieving the right balance. You want enough lumens from your light source to ensure sufficient foot candles on your desk. This balance can vary depending on the nature of your work and personal preferences.

For detailed tasks like reading small print, you might need more foot candles. On the other hand, for a cozy atmosphere in a café, you might prefer lower levels of light. It's all about finding what works best for your specific needs.

In conclusion, understanding the journey of light from lumens to foot candles helps us appreciate the complexity of lighting levels. It's not just about how bright a light source is; it's about how effectively that light reaches our workspace. So, the next time you sit at your desk or step into a room, remember that the interplay of lumens and foot candles is at work to provide you with the right amount of illumination for your tasks and comfort.

This chart provides a quick reference for the recommended foot candle levels in various room types, helping you understand how much light is ideal for each setting.

Stairway 5-10 FC
Corridor - General 5-10 FC
Corridor - Hospital 5-10 FC
Storage Room - General 5-20 FC
Restroom / Toilet 10-30 FC
Locker Room 10-30 FC
Lounge / Breakroom 10-30 FC
Loading Dock 10-30 FC
Lobby - Office/General 20-30 FC
Cafeteria - Eating 20-30 FC
Dormitory - Living Quarters 20-30 FC
Library - Stacks 20-50 FC
Mechanical / Electrical Room 20-50 FC
Retail Sales 20-50 FC
Workshop 30-75 FC
Classroom - General 30-50 FC
Conference Room 30-50 FC
Exhibit Space (Museum) 30-50 FC
Library - Reading / Studying 30-50 FC
Office - Open 30-50 FC
Office - Private / Closed 30-50 FC
Gymnasium - Exercise / Workout 20-30 FC
Gymnasium - Sports / Games 30-50 FC
Kitchen / Food Prep 30-75 FC
Laboratory (Classroom) 50-75 FC
Laboratory (Professional) 75-120 FC
Parking - Interior 5-10 FC