misterdogman
Well-Known Member
They say with CFLs dont look at lumens but wattage...some say just calculate lumens....whatever.
Provide a minimum of 3000 lumens per sq ft and 50 watts per sq ft at the same time AT least and your good....
here is some very useful formulas to calculate light in different ways...they help somewhat if you got a calulator...
of course i copied and pasted from the interwebnet thingy....
[SIZE=-1]DESIGN FORMULAS[/SIZE]
[SIZE=-1]Footcandles & Lumens[/SIZE]
[SIZE=-1]Footcandles (fc) = Total Lumens (lm) ÷ Area in Square Feet[/SIZE]
[SIZE=-1]1 Lux (lx) = 1 Footcandle (fc) x 10.76[/SIZE]
[SIZE=-1]Lux = Total Lumens ÷ Area in Square Meters[/SIZE]
[SIZE=-1]Calculating Light Level at a Point[/SIZE]
[SIZE=-1]For planes perpendicular to the direction of candlepower (Inverse Square Law):[/SIZE]
[SIZE=-1]Footcandles (fc) = I ÷ D2[/SIZE]
[SIZE=-1]Horizontal Footcandles (fch) = (I ÷ D2) x H[/SIZE]
[SIZE=-1]Vertical Footcandles (fcv) = (I ÷ D2) x L[/SIZE]
[SIZE=-1]Required Light Output/Fixture (Lumens) = (Maintained Illumination in Footcandles x Area in Square Feet) ÷ (Number of Fixtures x Coefficient of Utilization x Ballast Factor x Light Loss Factor)[/SIZE]
[SIZE=-1]Light Loss Factors (more on [/SIZE][SIZE=-1]Light Loss[/SIZE][SIZE=-1])[/SIZE]
[SIZE=-1]Light Loss Factor (LLF) = Ballast Factor x Fixture Ambient Temperature Factor x Supply Voltage Variation Factor x Lamp Position Factor x Optical Factor x Fixture Surface Depreciation Factor x Lamp Burnouts Factor x Lamp Lumen Depreciation Factor x Fixture Dirt Depreciation Factor x Room Surface Dirt Depreciation Factor[/SIZE]
[SIZE=-1]Lamp Burnout Factor = 1 - Percentage of Lamps Allowed to Fail Without Being Replaced[/SIZE]
[SIZE=-1]Zonal Cavity Method (determining cavity ratios)[/SIZE]
Provide a minimum of 3000 lumens per sq ft and 50 watts per sq ft at the same time AT least and your good....
here is some very useful formulas to calculate light in different ways...they help somewhat if you got a calulator...
of course i copied and pasted from the interwebnet thingy....
[SIZE=-1]DESIGN FORMULAS[/SIZE]
[SIZE=-1]Footcandles & Lumens[/SIZE]
[SIZE=-1]Footcandles (fc) = Total Lumens (lm) ÷ Area in Square Feet[/SIZE]
[SIZE=-1]1 Lux (lx) = 1 Footcandle (fc) x 10.76[/SIZE]
[SIZE=-1]Lux = Total Lumens ÷ Area in Square Meters[/SIZE]
[SIZE=-1]Calculating Light Level at a Point[/SIZE]
[SIZE=-1]For planes perpendicular to the direction of candlepower (Inverse Square Law):[/SIZE]
[SIZE=-1]Footcandles (fc) = I ÷ D2[/SIZE]
[SIZE=-1]I = Candlepower in candelas (cd)[/SIZE] [SIZE=-1]D = Direct distance between the lamp and the point where light level is calculated[/SIZE]
[SIZE=-1]Many workplanes are not perpendicular to the direction of light intensity, which is why calculating light level at a point is useful for such applications. In these cases, we often must determine light levels on workplanes that are not horizontal and perpendicular but tilted or even vertical. For tilted-horizontal or vertical planes:[/SIZE]
[SIZE=-1]Horizontal Footcandles (fch) = (I ÷ D2) x H[/SIZE]
[SIZE=-1]Vertical Footcandles (fcv) = (I ÷ D2) x L[/SIZE]
[SIZE=-1]I = Candlepower in candelas (cd)[/SIZE] [SIZE=-1]D = Direct distance between the lamp and the point where light level is calculated[/SIZE]
[SIZE=-1]H = Distance between the lamp and the point direct below on the workplane[/SIZE]
[SIZE=-1]L = Distance between that point and the point where light level is being calculated[/SIZE]
[SIZE=-1]D = Square Root of (H2 + L2) or D2 = H2 + L2[/SIZE]
[SIZE=-1]Calculating Average Light Level Throughout a Space (three formulas)[/SIZE][SIZE=-1]H = Distance between the lamp and the point direct below on the workplane[/SIZE]
[SIZE=-1]L = Distance between that point and the point where light level is being calculated[/SIZE]
[SIZE=-1]D = Square Root of (H2 + L2) or D2 = H2 + L2[/SIZE]
[SIZE=-1]Average Maintained Illumination (Footcandles) = (Lamps/Fixture x Lumens/Lamp x No. of Fixtures x Coefficient of Utilization x Light Loss Factor) ÷ Area in Square Feet[/SIZE] [SIZE=-1]Average Maintained Illumination (Footcandles) = (Total Lamps x Lumens/Lamp x Coefficient of Utilization x Light Loss Factor) ÷ Area in Square Feet[/SIZE]
[SIZE=-1]Average Maintained Illumination (Footcandles) = (Lamps in One Fixture x Lumens/Lamp x Coefficient of Utilization x Light Loss Factor) ÷ Area in Square Feet/Fixture[/SIZE]
[SIZE=-1]Lumen Method[/SIZE][SIZE=-1]Average Maintained Illumination (Footcandles) = (Lamps in One Fixture x Lumens/Lamp x Coefficient of Utilization x Light Loss Factor) ÷ Area in Square Feet/Fixture[/SIZE]
[SIZE=-1]Required Light Output/Fixture (Lumens) = (Maintained Illumination in Footcandles x Area in Square Feet) ÷ (Number of Fixtures x Coefficient of Utilization x Ballast Factor x Light Loss Factor)[/SIZE]
[SIZE=-1]Light Loss Factors (more on [/SIZE][SIZE=-1]Light Loss[/SIZE][SIZE=-1])[/SIZE]
[SIZE=-1]Light Loss Factor (LLF) = Ballast Factor x Fixture Ambient Temperature Factor x Supply Voltage Variation Factor x Lamp Position Factor x Optical Factor x Fixture Surface Depreciation Factor x Lamp Burnouts Factor x Lamp Lumen Depreciation Factor x Fixture Dirt Depreciation Factor x Room Surface Dirt Depreciation Factor[/SIZE]
[SIZE=-1]Lamp Burnout Factor = 1 - Percentage of Lamps Allowed to Fail Without Being Replaced[/SIZE]
[SIZE=-1]Zonal Cavity Method (determining cavity ratios)[/SIZE]
[SIZE=-1]Room Cavity Ratio (for regular rooms shaped like a square or rectangle) = [5 x Room Cavity Depth x (Room Length + Room Width)] ÷ (Room Length x Room Width)[/SIZE] [SIZE=-1]Room Cavity Ratio (for irregular-shaped rooms) = (2.5 x Room Cavity Depth x Perimeter) ÷ Area in Square Feet[/SIZE]
[SIZE=-1]Ceiling Cavity Ratio = [5 x Ceiling Cavity Depth x (Room Length x Room Width)] ÷ (Room Length x Room Width)[/SIZE]
[SIZE=-1]Floor Cavity Ratio = [5 x Floor Cavity Depth x (Room Length x Room Width)] ÷ Room Length x Room Width[/SIZE]
[SIZE=-1]Ceiling Cavity Ratio = [5 x Ceiling Cavity Depth x (Room Length x Room Width)] ÷ (Room Length x Room Width)[/SIZE]
[SIZE=-1]Floor Cavity Ratio = [5 x Floor Cavity Depth x (Room Length x Room Width)] ÷ Room Length x Room Width[/SIZE]