Lighting is essential for various reasons, depending on the environment. From visual and decorative to practical and utilitarian, the right light level can make a significant difference.
Not all lighting systems work the same, and the light you need in your space will depend heavily on the size of the room in question and what activities you’ll need to do it in it. It is also important to note that two rooms of the same size may require different levels of light based on the function of each. Let’s take a more in-depth look into how light levels are determined and the best light levels for all environments.
Measuring Light Levels
The most common measurements for the illumination of a space are lux and foot-candles. These units measure the amount of light or lumens that fall onto a surface in a given square foot or meter.
What Is a Lumen?
A lumen is the unit of measurement that quantifies the amount of light visible to the human eye. When you purchase a light bulb, you may notice the number of lumens advertised on the packaging. Typically, the higher the lumen output, the brighter or more intense the light source is.
What Is a Foot-Candle?
A foot-candle is a measurement of light intensity based on the number of lumens per square foot. Foot-candles and lux measure the intensity of light based on a particular area, and within the industry, many professionals use both metrics in their work. For foot-candles, specifically, one food-candle equals one lumen per square foot.
What Is a Lux
Lux is another unit of measurement that describes the number of lumens falling on a surface. However, the lux bases its measurements on lumens per square meter. Similar to foot-candles, one lux is equal to one lumen per square meter.
For example, if you have a light source with 1,000 lumens, and all those 1,000 lumens extend over a surface area of one square meter, you’d have an illuminance of 1,000 lux. If we apply the same number of lumens over 10 times the area—or 10 square meters—the illuminance or lux would decrease to a less intense and dimmer 100 lux.
Foot-Candles To Lux Conversions
Since these two terms are both common in the lighting industry, it is vital to understand the conversion from foot-candles to lux to determine the light level of a light source. One foot-candle is equal to approximately 10 lux. For example, if a room were to have a light level of 30 foot-candles, the lux level would be 300.
A photometric study is the study and measurement of light. This study can recommend the average or maximum and minimum foot-candles or lux for a specific space by using light study-specific software.
Lighting for Various Environments
Lighting should not be the same across the board in office spaces. Each designated area should have a specific light level with the purpose of enhancing the space. For example, general spaces, such as open, cubicle-style areas and conference rooms, should have an illuminance of roughly 30 foot-candles. This lighting is bright without being distracting to those who often work with bright monitors already. On the other hand, 10 foot-candles is an appropriate light level for a reception area where a more welcoming ambiance is necessary.
Retail and Grocery Stores
Retail stores have similar light levels to office spaces. You’ll want to illuminate merchandise with bright, high-intensity lighting to display items accurately and to their best advantage. Therefore, merchandise areas and food sections should have an illumination level of 50 foot-candles.
Stock areas and main concourse areas, such as a walkway in a mall, can use slightly lower light levels—perhaps 30 foot-candles—as the slightly less bright light will not affect the area the way soft lighting on a rack of dresses could alter a shopper’s opinion of them.
The lighting levels in restaurants vary considerably based on the specific location in question. For example, the light level of an LED cooler light in the kitchen freezer and the foot-candles in the dining room do not need to be nearly as high as the kitchen and prep areas require. The kitchen and prep areas should be closer to 50 foot-candles to ensure safety when the chefs are creating dishes. Dining rooms and the other regions can be as low as 5 to 10 foot-candles.
The best light level for warehouse facilities varies greatly depending on the type of work that takes place there. For complicated assembly processes or fine material processing, anywhere from 50 to 300 foot-candles may be necessary to illuminate the space accurately and safely. For simpler processing and shipping, 30 foot-candles is an appropriate amount of lighting.
If the warehouse simply houses items, foot-candle measurements as low as 5 to 10 will provide enough light for the space.
Proper lighting is imperative to medical practices. Hallways, waiting rooms, and patient rooms do not need to be too bright, as this can be overwhelming to visitors. However, areas containing medical records and nursing stations should utilize 30 foot-candles, and the rooms where medical procedures occur can sometimes require upwards of 10,000 foot-candles, depending on the area’s methods.
Home lighting often depends on the ambiance you are trying to achieve. For example, light levels for bedrooms and living rooms can range anywhere from 10 to 20 foot-candles, depending on the brightness you are looking for in these spaces.
Like commercial kitchens, you should have higher light levels, such as 50 foot-candles, on stovetops and prep counters, with lower levels, such as 20 to 30 foot-candles, in dining spots and general kitchen spaces.
Determining the best lighting levels for all environments depends on several factors, including the size of the space and the tasks and activities that will occur in the area. For more detailed and dangerous environments, a more significant amount of light will be necessary. Less light or lower foot-candles are acceptable in less tactical spaces. Follow these general guidelines of recommended foot-candles based on location and tasks for the best lighting in each area.