Example 1: Calculate Lighting Fixture’s Lumen and Diameter of Illumination at surface having following details.
- Required illumination at surface is 1390 Lux
- The distance from Lighting Fixture to illumination surface is 3 Meter.
- The Fixture Beam Angle is 10 Degree.
Calculation:
- Required Lux at Surface (E2) =1390 Lux.
- Distance between Lighting Fixture and Surface (D) = 3 Meter.
- Fixture Beam Angle (ϕ)= 10°
- Irradiance at 1.0 meter (E1)= DxDxE2
- Irradiance at 1.0 meter (E1)=1390x3x3 =12510 Lumen / M2
- Irradiance at 1.0 meter (E1)= 12510 Lumen / M2
- Solid Angle of The Lamp (Ω) =2xπx(1-COS(ϕ/2))
- Solid Angle of The Lamp (Ω) =2×3.14x(1-COS(10/2)) =6.28x(1-0.996)
- Solid Angle of the Lamp (Ω) =0.0239 Steradian.
- Required Lumen of Lighting Fixtures= E1x Ω
- Required Lumen of Lighting Fixtures=12510×0.0239
- Required Lumen of Lighting Fixtures=299 Lumen.
- Illumination Diameter at surface =0.018xDx ϕ
- Illumination Diameter at surface =0.018x3x10
- Illumination Diameter at surface =0.54 Meter.
Example 2: Calculate Lighting Fixture’s Beam Angle and Illumination Diameter at surface having following details.
- Required illumination at surface is 22 Lux
- Lighting Fixture Lumen is 1547 Lumen.
- The distance from Lighting Fixture to illumination surface is 4 Meter.
Calculation:
- Required Lux at Surface (E2) =22 Lux.
- Distance between Lighting Fixture and Surface (D) = 4 Meter.
- Irradiance at 1.0 meter (E1)= DxDxE2
- Irradiance at 1.0 meter (E1)=4x4x22 =352 Lumen / M2
- Irradiance at 1.0 meter (E1)= 352 Lumen / M2
- Solid Angle of The Lamp (Ω) = Lumen of Lighting Fixtures / E1
- Solid Angle of the Lamp (Ω) =1547 / 352
- Solid Angle of the Lamp (Ω) =4.394 Steradian.
- Solid Angle of The Lamp (Ω) =2xπx(1-COS(ϕ/2))
- 39 =2×3.14x(1-COS(ϕ/2))
- Fixture Beam Angle (ϕ)=145°
- Illumination Diameter at surface =0.018xDx ϕ
- Illumination Diameter at surface =0.018x4x145
- Illumination Diameter at surface =10.44 Meter.
Example 3: Calculate Lux Level and Illumination Diameter at surface having following details.
- Lighting Fixture Lumen is 299 Lumen.
- The distance from Lighting Fixture to illumination surface is 3 Meter.
- The Fixture Beam Angle is 10 Degree.
Calculation:
- Required Lux at Surface (E2) =1390 Lux.
- Distance between Lighting Fixture and Surface (D) = 3 Meter.
- Fixture Beam Angle (ϕ)= 10°
- Solid Angle of The Lamp (Ω) =2xπx(1-COS(ϕ/2))
- Solid Angle of The Lamp (Ω) =2×3.14x(1-COS(10/2)) =6.28x(1-0.996)
- Solid Angle of the Lamp (Ω) =0.0239 Steradian.
- Lumen of Lighting Fixtures= E1x Ω
- 299= E1x0.0239
- Irradiance at 1.0 meter (E1)= Lumen of Lighting Fixtures / Ω
- Irradiance at 1.0 meter (E1)=299 / 0.0239
- Irradiance at 1.0 meter (E1)= 12506 Lumen / M2
- Lux at Surface (E2) = E1 / (DxD)
- Lux at Surface (E2) =12506 / (3×3)
- Lux at Surface (E2) =1389.5 Lux
- Illumination Diameter at surface =0.018xDx ϕ
- Illumination Diameter at surface =0.018x3x10
- Illumination Diameter at surface =0.54 Meter.
May 01, 2018 at 10:10PM by Department of EEE, ADBU: https://ift.tt/2AyIRVT
