Simple Calculation of Flood Light, Facade Light, Street Light & Signage Light

Simple Calculation of Flood Light, Facade Light, Street Light & Signage Light:

Introduction:

• Outdoor Lighting can be classified according to the location where it can be installed or its function which use for highlight landscape area.
• Outdoor Lighting can be classified as

1. Flood Lighting,
2. Facade Lighting and
3. Signage Lighting
4. Street Light

(A) General Outdoor Flood Lighting:

• Normally Pole mounted floodlights are used to illuminate general lighting area of parking lots and storage yards. 
• There are three factor should be consider while designing of outdoor flood lighting.

1. Mounting Height.
2. Spacing
3. Aiming Distance.
4. Horizontal Aiming.

1) Mounting Height:

• Mounting height should be one half the distance across the area to be lighted.
• If the area to be lighted is 16 Meter, the lowest recommended mounting height is 8 Meter. 
• Mounting height = 1/2 distance to be lighted
• 1/2 (16 Meter.) = 8 Meter. 

2) Spacing:

• When more than one Luminar / pole is required than distance between two adjacent luminar / Pole is 4 times Mounting height of luminar /pole.
• If the mounting height of luminar /Pole is 8 Meter than distance between adjacent Luminar is 32 Meter.
• Pole Spacing = 4 x mounting height.
• 4 (8 Meter pole) = 32 Meter between poles

3) Vertical Aiming:

• The fixture should be aimed 2/3 of the distance across the area to be lighted and at least 30 degrees below horizontal. 
• If the area to be lighted is 16 Meter across, the recommended aiming point is 10.6 Meter.
• Aiming point = 2/3 Distance to be lighted.
• 2/3 (16 Meter) = 10.6 Meter aiming point
• To minimize glare, the recommended aiming point distance should never exceed twice the mounting height.
• If a pole is 8 Meter high, the vertical aiming point should not exceed 16 Meter.  
• 2 (8 Meter mounting height) = 16 Meter. 

4) Horizontal Aiming:

• When two floodlights is mounted to a single pole then horizontal aiming also must be considered.
• Each floodlight should be vertically aimed according to the two-thirds rule. 
• The floodlights should be aimed up to 90 degrees apart. 

(B) Facade Lighting:

• Normally Facade Lighting are used to illuminate Building area from Outer Side. 
• There are three factor should be consider while designing of outdoor Facade Lighting.

1. Setback
2. Spacing
3. Aiming

1) Setback:

• The recommended setback should be 3/4 times the building height. 
• If a building is 10 Meter tall, the recommended setback is 7.5 Meter from the building. 
• If the locating the floodlight closer to the building will sacrifice uniformity and If setting it further back will result in loss of efficiency.
• Setback distance = 3/4 x Building height
• Setback distance =3/4 x (10 Meter) = 7.5 Meter 

2) Spacing:

• Spacing of floodlights should not be exceeding two times the setback distance. 
• If the setback is 7.5 Meter the floodlights should not be placed more than 15 Meter apart.
• Spacing = 2 x setback distance
• Spacing=2 x 5  = 15 Meter

3) Aiming:

• The floodlight should be aimed at least 2/3 the height of the building.
• If a building is 10 Meter high, the recommended aiming point is approximately 6.6 Meter high. 
• After installation aiming can be adjusted to produce the best fine appearance. 
• Aiming Point = 2/3 x Building Height.
• Aiming Point =2/3 (10 Meter) = 6.6 Meter high

(C) Sinage Lighting:

• Normally Sinage Lighting are used to illuminate Sinage Board either Floor Mounted or Pole Mounted
• There are three factor should be consider while designing of Sinage Board Lighting.

1. Setback
2. Spacing
3. Aiming

1) Setback:

• When using floodlights to light a sinage, the setback should be 3/4 the sign height
• If the sinage height is 18 Meter then the setback distance would be 13.5 Meter. 
• If the floodlight closer to sinage will sacrifice uniformity while setting it further back will in a loss of efficiency.
• Setback distance = 3/4 x sinage height
• Setback distance =3/4 (18 Meter) = 13.5 Meter.

2) Spacing:

• The spacing floodlights should not be exceed two times the setback distance. 
• If the setback is 13.5 Meter, the floodlights should not be placed more than 27 Meter apart. 
• Spacing = 2 x setback distance.
• Spacing = 2 x 5 (Meter) = 27 Meter.

3) Aiming:

• The floodlight should be aimed at least 2/3 up the sign.
• If a sign is 18 Meter tall, then the floodlight should be aimed approximately 12 Meter high. 
• Aiming can be adjusted to produce the best appearance. 
• Mounting a full or upper visor to the floodlight can reduce unwanted glare. 
• Aiming point = 2/3 x sign height
• Aiming point =2/3 (18 Meter) = 12 Meter high

Street Light Pole Height & Spacing (as per CPWD):

• There are four type of Street Light Pole arrangement.
• One side Type.
• Staggered Type.
• Opposite Type.
• Central Type.
• As per CPWD we can calculate Pole Height and Spacing as per under

(1) One side Street Light Pole arrangement.

• Pole Height = Width of Road.
• Pole Spacing = 3 to 4 Times Height of Pole.
• If the Road width is 8 Meter than
• Pole Height=8 Meter
• Pole Spacing =24 to 32 Meter.

(2) Staggered Type Street Light Pole arrangement.

• Pole Height = 0.8 time Width of Road.
• Pole Spacing = 3 to 4 Times Height of Pole.
• If the Road width is 8 Meter than
• Pole Height=6.4 Meter
• Pole Spacing =24 to 32 Meter.

(3) Opposite side Street Light Pole arrangement.

• Pole Height = 0.5 time Width of Road.
• Pole Spacing = 3 to 4 Times Height of Pole.
• If the Road width is 8 Meter than
• Pole Height=6.4 Meter
• Pole Spacing =24 to 32 Meter.

(4) Central Street Light Pole arrangement.

• Pole Height = 0.8 time Width of Road.
• Pole Spacing = 3 to 4 Times Height of Pole.
• If the Road width is 8 Meter than
• Pole Height=4 Meter
• Pole Spacing =24 to 32 Meter.