Number of Lights Formula:
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Definition: This calculator estimates the number of high bay LED lights needed for a given area based on desired illumination level (foot-candles), area size, and light output.
Purpose: It helps facility managers, electricians, and lighting designers determine how many high bay fixtures are required for proper illumination in industrial or commercial spaces.
The calculator uses the formula:
Where:
Explanation: The total lumens needed (FC × Area) is divided by the lumens provided by each fixture to determine how many fixtures are required.
Details: Accurate lighting calculations ensure adequate illumination for safety and productivity while avoiding over-lighting which wastes energy.
Tips: Enter the desired foot-candle level (typically 30-100 fc for industrial spaces), area in square feet, and lumens per fixture (default 20,000 lm). All values must be > 0.
Q1: What are typical foot-candle requirements?
A: Warehouses typically need 10-30 fc, manufacturing 30-100 fc, and retail spaces 50-100 fc depending on tasks.
Q2: How do I find lumens per light?
A: Check the product specifications of your high bay LED fixtures (typically 15,000-40,000 lumens).
Q3: Does this account for light loss factors?
A: No, consider multiplying the result by 1.2-1.5 to account for fixture depreciation and dirt accumulation.
Q4: What's the difference between lux and foot-candles?
A: 1 foot-candle = 10.764 lux. Foot-candles are commonly used in the US, lux internationally.
Q5: How does mounting height affect the calculation?
A: Higher mounting may require more fixtures or higher lumen output to achieve the same FC at floor level.