Table of Contents
- 1 How are footcandles calculated?
- 2 What is the formula for calculating lumens?
- 3 How many footcandles do plants need?
- 4 How many lumens does a fluorescent bulb produce?
- 5 How do you calculate the illuminance of a room?
- 6 How is indoor illuminance calculated?
- 7 How to calculate the lumens of a CFL light?
- 8 How to calculate the number of light fixtures?
How are footcandles calculated?
Multiply the Length times the Width of the Room to get the Room Square Footage. For example, if the room is 10 feet wide and 10 feet long, the Room Square Footage will be 100 square feet. A foot-candle is how bright the light is one foot away from the source.
What is the formula for calculating lumens?
Determine the Needed Lumens A lumen is a unit measurement of light. 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.
How do you convert lumens to footcandles?
One foot-candle equals 10.76 lumens (a lumen is considered the same as lux, which is what most modern light meters calculate their measurements in), so in order to convert your foot-candles to lumens, you will need to take the amount of foot-candles measured and multiply by 10.76 to get the number of lumens.
How do you calculate illuminance?
The equation of the illuminance, E, of a small light source is E = P/ 4(pie)d^2, where P is the luminous flux (in lumens, lm) of the source and d is its distance from the surface. Suppose the luminous flux of a desk lamp is 1200 lm.
How many footcandles do plants need?
Plants referred to as low light intensity plants generally should receive between 50 and 250 foot-candles. Medium-light plants prefer 250 to 1,000 foot-candles. Best growth occurs above 750 foot-candles unless plants also receive extended periods of direct sunlight.
How many lumens does a fluorescent bulb produce?
Well, fluorescent tubes can only produce about 50-100 lumens per watt (lm/w). This is because a lot of the energy that is produced is wasted because it is transformed into heat instead of light.
How many lumens is a 40 watt bulb?
Lumens equals brightness!
| How Many Lumens Do You Need? More Lumens = More Light | ||
|---|---|---|
| 100 W | 1600 | up to 72 W |
| 75 W | 1100 | up to 53 W |
| 60 W | 800 | up to 43 W |
| 40 W | 450 | up to 29 W |
Are lumens and footcandles the same?
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 do you calculate the illuminance of a room?
The average illuminance
- a = length of the room in meters;
- b = width of the area in meters;
- h = distance in meters between the lighting fixtures and the plane on which you have to measure illuminance (eg height of lighting fixtures 2.80 m, worktop at height 0.8 m, h = 2.80 to 0.8 = 2).
How is indoor illuminance calculated?
Calculation in 8 steps
- Total wattage of fixtures: Total wattage of fixtures = Number of lamps x each lamp’s watt. Total wattage of fixtures = 2 × 32 = 64 Watt.
- Lumen per fixtures. Lumen per fixtures = Lumen efficiency (Lumen per Watt) x each fixture’s watt. Lumen per fixtures = 85 x 64 = 5440 Lumen.
- Number of fixtures.
How to calculate the lumens of a foot candle?
We use the following equation: lumens = lux * area You can use illumination units of lux or foot candles. If you want to recalculate between these units, remember that one foot-candle equals 10.764 lux.
What does a foot candle light guide mean?
FOOT CANDLE LIGHT Guide. FOOTCANDLE LIGHT GUIDE. Footcandles are the most common unit of measure used by lighting professionals to calculate light levels in businesses and outdoor spaces. A footcandle is de˜ned as the illuminance on a one square foot surface from a uniform source of light.
How to calculate the lumens of a CFL light?
For the maximum foot prep level of 100 footcandles, the calculation would be 100 footcandles X 120 square feet = 12,000 lumens. For compact fluorescent lights (CFL) the illuminance tends to be about 40 to 70 lumens per Watt of power draw (incandescent lights are more like 10-17 lumens/Watt).
How to calculate the number of light fixtures?
Calculating Number of Lamps And Fixtures And Spacing. Required No. of Fixtures = (Lumens/Lamp x No. of Lamps x Coefficient of Utilization x Light Loss Factor x Area in Square Feet) ÷ (Lumens/Lamp x Lamps/Fixture x Coefficient of Utilization x Light Loss Factor) Required Lamps = Required Lumens ÷ Initial Lumens/Lamp.