ILLUMINATION ENGINEERING – PART – 13 – THUMB RULES OF FACADE, SIGN, FLAG, GERNEAL AREA AND MONUMENT LIGHTING

 TYPES OF FLOOD LIGHTING APPLICATIONS

1. Facade (the face or front of a building) lighting  

2. Sign (a public display of a message) lighting

3. Flag lighting 

4. General area lighting and 

5. Monument lighting

FACADE LIGHTING - When lighting building facades with ground-mounted floodlights, three factors are to be considered.

1. Setback distance – Distance between the building and the floodlight projector.

The recommended setback is 3/4 times the building height. 

If a building is 40 feet tall, the recommended setback is 30 feet from the building.  Locating the floodlight closer to the building will sacrifice uniformity; setting it farther back will result in loss of efficiency.

2. Spacing – Distance between floodlight projectors

The rule of thumb for spacing floodlights is not to exceed two times the setback distance. 

If the setback is 30 feet, the floodlights should not be placed more than 60 feet apart.

3. Aiming distance – Distance aimed for flood lighting the front side of the building

The floodlight should be aimed at least 2/3 the height of the building. 

For example, if a building is 40 feet high, the recommended aiming point is approximately 27 feet high. 

After installation is complete, aiming can be adjusted to produce the best appearance.  Mounting a full or upper visor to the floodlight can reduce unwanted spill light.

SIGN LIGHTING - When lighting a sign with ground-mounted floodlights, three factors to be considered.

1. Setback distance - Distance between the building and the floodlight projector.

When using ground-mounted floodlights to light a sign, the recommended setback is a distance equal to 3/4 the sign height. 

For example, the setback distance for a 16 foot by 8 foot sign would be 6 feet.  

Locating the floodlight closer will sacrifice uniformity while setting it farther back will result in a loss of efficiency. 

2. Spacing - Distance between floodlight projectors

The rule of thumb for spacing floodlights is not to exceed two times the setback distance. 

If the setback is 6 feet, the floodlights should not be placed more than 12 feet apart.

3. Aiming distance - Distance aimed for flood lighting the front side of the building

The floodlight should be aimed at least 2/3 up the sign. 

For example, if a sign is six feet tall, then the floodlight will be aimed at approximately four feet high. 

After installation is complete, aiming can be adjusted to produce the best appearance.  Mounting a full or upper visor to the floodlight can reduce the unwanted glare.

FLAG LIGHTING - Ground-mounted floodlights are often used to provide illumination for flags. 
The most important factors to be considered are: Wattage, Distribution, Setback, Spacing, Aiming, Fixtures.

Depending on pole height, flag size, and ambient light levels, the wattage of lamp used in the lighting fixture should be carefully considered when choosing the appropriate fixture for your flag lighting application.

1. Setback distance - Distance between the building and the floodlight projector

The recommended setback for lighting a flag is 1/3 times the pole height. 

If the pole is 40' tall, the floodlight should be set back a distance of 13.33' away from the pole.

GENERAL AREA LIGHTING - Pole mounted floodlights are commonly used for general area lighting applications such as parking lots and storage yards.

The factors to be considered are mounting height, spacing distance, vertical aiming and horizontal aiming.

1. Mounting Height - It is the height of the lamp to be fixed at the top of the pole

The recommended mounting height is one half the distance across the area to be lighted.  If the area to be lighted is 40 feet across, the lowest recommended mounting height is 20 feet.

Mounting height = 1/2 distance to be lighted [1/2 (40 ft.) = 20 ft.]

2. Spacing distance - Distance between the two poles

When more than one pole is added, pole placement is a concern.  

The "4 times" rule of thumb for spacing indicates that a pole should be placed four times the mounting height from the adjacent poles.  

If a floodlight is mounted on a 20 foot pole, space the poles 80 feet apart.

Pole Spacing = 4 x mounting height [4 (20 ft. pole) = 80 feet between poles]

3. Vertical Aiming

A single floodlight uses the two-thirds rule of thumb for vertical aiming.  

The fixture is 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 40 feet across, the recommended aiming point is 27 feet.

Aiming point = 2/3 across distance to be lighted [2/3 (40 ft.) = 27 ft. aiming point]

Additionally, to minimize glare, the recommended aiming point distance should never exceed twice the mounting height.  

If a pole is 20 feet high, the vertical aiming point should not exceed 40 feet out. 

4. Horizontal Aiming

When an additional floodlight is added to a single pole, horizontal aiming also must be considered.  

First, each floodlight should be vertically aimed according to the two-thirds rule above. 

MONUMENT (LIGHTING (An important site that is marked and preserved as public property)

1. Most prominent feature

Select the single most prominent characteristic of the statue or monument, possibly a face or emblem, and illuminate it with a single spot. 

More than one spot may be needed to provide visual interest from all viewing locations.

2. Texture (the essential quality of something) & Three-dimensional quality

Develop a grazing effect by placing fixtures at the base of the statue, aimed straight up.  Strong shadows will highlight the texture and three-dimensional quality of the work.  

This effect may be produced with either spot or horizontal spot distributions. 

3. Profile, Silhouette (a drawing of the outline of an object; filled in with some uniform color)

* Should the statue be located in front of a wall or similar surface such as a row of trees, consider lighting this background surface so that the dark statue is seen in silhouette against the light background.  

* This technique is particularly effective in accenting the overall shape, such as a rider on horseback.  

* Provide sufficient background illuminance or brightness so that a strong accent effect exists between the background and statue.