A foot-candle (or foot-candle, fc, lm/ft2, or ft-c) is a measurement of light intensity. One foot-candle is defined as enough light to saturate a one-foot square with one lumen of light. Source: FSG.
How do I calculate foot candles?
To determine the needed lumens, you will need to multiply your room square footage by your room foot-candle requirement. For example, a 100 square foot living room, which needs 10-20 foot-candles, will need 1,000-2,000 lumens. A 100 square foot dining room, which needs 30-40 foot-candles, will need 3,000-4,000 lumens.
What does 10 foot candles mean?
A foot-candle equals one lumen per square foot. This is a British measurement. Using the metric system, a lumen is measured by a square meter or a lux. Thus a foot-candle is equivalent to approximately 10 lux or 10.57 lux.
How many foot candles is sunlight?
Full daylight typically equals about 1,000 foot-candles, while an overcast day would have only 100 foot-candles of light. Twilight produces just 1 foot-candle, while a night with a full moon has 0.01 foot-candle and an overcast night has only 0.00001 foot-candle.
What do foot-candles measure?
Believe it or not, foot candles are the most common unit of measure used by lighting professionals to calculate light levels in businesses and outdoor spaces. In a nutshell, a foot candle is a measurement of light intensity and is defined as the illuminance on a one-square foot surface from a uniform source of light.
How many foot-candles do plants need?
Plants referred to as low light intensity plants generally should receive between 50 and 250 foot-candles. Under artificial light, a few plants in this group can be maintained at as little as 10 foot-candles. Low-light plants should receive between 10 and 15 watts of fluorescent light per square foot of growing space.
How many lumens do I need for a 12×12 room?
As a handy rule of thumb, a sitting room or bedroom will generally require around 10-20 lumens per square foot, while a bathroom or kitchen will need a stronger level of lighting, at around 70-80 lumens per square foot. To work out the lumens you need, simply multiply the square footage of the room by this figure.
How many foot candles are in a 100 watt bulb?
Their efficiency is in the range of 4 lumens per watt. This means that a 100 watt bulb will generate 400 lumens – TOTAL. (Here’s the big leap) Now, if we COULD reflect all of that 400 lumens onto 1 square foot we would get a light intensity of 400 foot candles.
Are lumens the same as lux?
The difference between lumen and lux is that the lux takes into account the area over which the luminous flux (lumens) is spread. A flux of 1000 lumens, concentrated into an area of one square metre, lights up that square metre with an illuminance of 1000 Lux.
How bright is .5 foot-candles?
How Bright Is 5 Foot Candles? The brightness of 5-foot candles is generally a more dim light that you’d expect in either a corridor in your home or in a typical store environment for a more commercial example.
What is a good foot-candle reading?
A requirement of 20 foot candles is recommended for general spaces in offices. In areas where reading and detailed tasks are carried out, 50 foot candles of lighting is sufficient. Conference rooms and other areas where visually challenging tasks are occasionally performed may incorporate between 10-20 foot candles.
What do you mean by lux?
Definition of lux
: a unit of illumination equal to the direct illumination on a surface that is everywhere one meter from a uniform point source of one candle intensity or equal to one lumen per square meter.
What is the difference between lux and foot-candle measurement?
Foot-candles and lux measure the same thing—the amount of visible light that falls on a surface. The difference is that the foot-candle uses the Imperial standard measuring system (feet, pounds, etc.), while the lux uses the metric system (meters, grams, etc.).
What is the difference between lux and FC?
Footcandles is the Imperial measurement and Lux is the Metric measurement of the same thing. 1 footcandle = 10.764 lux. Both quantify the amount of light falling on a specific point or object.
How many foot candles are in a restaurant?
Well, the IES recommends between 3 and 6 footcandles at the dining table (depending on age)—but only 16% of restaurants reached this brightness—and most of those were deemed “too bright” by our surveyors. The vast majority of restaurants, 75%, had significantly lower illuminance levels—below 1.3 fc at the dining plate.
How many foot candles is a lumen?
Therefore, the light of one candle radiating through one steradian is one lumen. It follows that one footcandle is equal to one lumen per square foot since in the definition we said that one candle power is equal to one lumen per steradian.
How do I know how many lumens I need?
Lumens calculation summary
Multiply your room square footage by the footcandle requirement. For example, a 100-square foot living room, which needs 20 footcandles, will need 2,000 lumens. A 100-square foot dining room, which needs 40 footcandles, will need 4,000 lumens 2 (see PDF and complete footcandle index).
