A Comprehensive Guide to Lighting Distribution Types for Illuminating Your Space

Lighting distribution is the way light is spread or projected from a light source. It affects the quality, coverage, and appearance of the illuminated space. Different types of lighting distribution are suitable for different applications, such as walkways, roadways, parking areas, or large spaces.

In this guide, you`ll learn about the five main types of lighting distribution patterns, from Type I to Type V, and how to choose the best one for your lighting project. You`ll also discover some tips and techniques to optimize your lighting design and installation.

What is Lighting Distribution?

Lighting distribution is the horizontal and vertical pattern of light emitted by a light source. It depends on the shape, size, and position of the light source, as well as the reflectors, lenses, or diffusers that modify the light output.

The Illuminating Engineering Society of North America (IESNA) has classified lighting distribution into five categories, based on the width of the light pattern and the amount of light that reaches certain vertical angles. These categories are:

Type I: A narrow, symmetrical light pattern for fixtures located in the middle of a walkway or a narrow path.
Type II: A slightly wider, symmetrical light pattern for fixtures located at the edge of a wide path, alley, or roadway.
Type III: A medium-wide, asymmetrical light pattern for fixtures located along the side of a roadway, parking area, or lawn.
Type IV: A wide, asymmetrical light pattern for fixtures that project light forward, with little light behind the fixture. Also known as forward throw or asymmetric distribution.
Type V: A very wide, symmetrical light pattern for fixtures that provide uniform illumination over a large area.

Each type of lighting distribution has its advantages and disadvantages, depending on the application and the desired lighting effect. In the following sections, we`ll explain each type in more detail and show you some examples of where and how to use them12345

Type I Lighting Distribution

Type I lighting distribution provides a narrow, symmetrical light pattern for fixtures located in the middle of a walkway or a narrow path. The width of the light pattern is about equal to the mounting height of the fixture. For example, if the fixture is mounted at 10 feet, it will cast light up to 10 feet wide on both sides of the fixture.

Type I fixtures are good for:

Sidewalks
Narrow walkways
Border lighting

Type I fixtures are not suitable for:

Wide paths
Roadways
Large spaces

Here are some examples of Type I lighting distribution:

To achieve Type I lighting distribution, you can use fixtures that have a circular or square shape, or fixtures that have a rectangular shape with a symmetrical reflector or lens. You can also use fixtures that have an adjustable beam angle, such as LED spotlights or floodlights, and set them to a narrow angle.

Some tips and techniques for using Type I lighting distribution are:

Mount the fixtures at a height that is appropriate for the width of the walkway or path. If the fixtures are too high, the light will be too dim and create dark spots. If the fixtures are too low, the light will be too bright and create glare.

Space the fixtures evenly along the walkway or path, with a distance that is equal to or less than the mounting height of the fixture. For example, if the fixture is mounted at 10 feet, the distance between the fixtures should be 10 feet or less. This will ensure a uniform and continuous light level along the walkway or path.

Avoid placing the fixtures near walls or other obstructions that may block the light or create shadows. If possible, use fixtures that have a low profile or a recessed design, so they don`t protrude from the ceiling or the ground.

Type II Lighting Distribution

Type II lighting distribution provides a slightly wider, symmetrical light pattern for fixtures located at the edge of a wide path, alley, or roadway. The width of the light pattern is about 1.5 times the mounting height of the fixture. For example, if the fixture is mounted at 10 feet, it will cast light up to 15 feet wide on both sides of the fixture.

Type II fixtures are best suited for:

Wide paths
Alleys
Side streets

Type II fixtures are not suitable for:

Narrow walkways
Roadways
Large spaces

Here are some examples of Type II lighting distribution:

To achieve Type II lighting distribution, you can use fixtures that have a rectangular shape with a symmetrical reflector or lens, or fixtures that have an adjustable beam angle, such as LED spotlights or floodlights, and set them to a medium-wide angle.

Some tips and techniques for using Type II lighting distribution are:

Mount the fixtures at a height that is appropriate for the width of the path, alley, or roadway. If the fixtures are too high, the light will be too dim and create dark spots. If the fixtures are too low, the light will be too bright and create glare.

Space the fixtures evenly along the edge of the path, alley, or roadway, with a distance that is equal to or less than the mounting height of the fixture. For example, if the fixture is mounted at 10 feet, the distance between the fixtures should be 10 feet or less. This will ensure a uniform and continuous light level along the path, alley, or roadway.

Avoid placing the fixtures near walls or other obstructions that may block the light or create shadows. If possible, use fixtures that have a low profile or a recessed design, so they don`t protrude from the ceiling or the ground.

Type III Lighting Distribution

Type III lighting distribution provides a medium-wide, asymmetrical light pattern for fixtures located along the side of a roadway, parking area, or lawn. The width of the light pattern is about 2.75 times the mounting height of the fixture. For example, if the fixture is mounted at 10 feet, it will cast light up to 27.5 feet wide on the street side of the fixture, and up to 10 feet wide on the house side of the fixture.

Type III fixtures are ideal for:

Roadways
General parking areas
Lawns

Type III fixtures are not suitable for:

Narrow walkways
Wide paths
Large spaces

To achieve Type III lighting distribution, you can use fixtures that have a rectangular shape with an asymmetrical reflector or lens, or fixtures that have an adjustable beam angle, such as LED spotlights or floodlights, and set them to a wide angle.

Some tips and techniques for using Type III lighting distribution are:

Mount the fixtures at a height that is appropriate for the width of the roadway, parking area, or lawn. If the fixtures are too high, the light will be too dim and create dark spots. If the fixtures are too low, the light will be too bright and create glare.

Space the fixtures evenly along the side of the roadway, parking area, or lawn, with a distance that is equal to or less than the mounting height of the fixture. For example, if the fixture is mounted at 10 feet, the distance between the fixtures should be 10 feet or less. This will ensure a uniform and continuous light level along the roadway, parking area, or lawn.

Avoid placing the fixtures near walls or other obstructions that may block the light or create shadows. If possible, use fixtures that have a low profile or a recessed design, so they don`t protrude from the ceiling or the ground.

Type IV Lighting Distribution

Type IV lighting distribution provides a wide, asymmetrical light pattern for fixtures that project light forward, with little light behind the fixture. The width of the light pattern is about 2.75 times the mounting height of the fixture. For example, if the fixture is mounted at 10 feet, it will cast light up to 27.5 feet wide on the street side of the fixture, and up to 5 feet wide on the house side of the fixture.

Type IV fixtures are also known as forward throw or asymmetric fixtures. They are best suited for:

Wall-mounted fixtures
Specific area lighting
Perimeter lighting

Type IV fixtures are not suitable for:

Narrow walkways
Wide paths
Large spaces

Here are some examples of Type IV lighting distribution:

To achieve Type IV lighting distribution, you can use fixtures that have a rectangular shape with an asymmetrical reflector or lens, or fixtures that have an adjustable beam angle, such as LED spotlights or floodlights, and set them to a very wide angle.

Some tips and techniques for using Type IV lighting distribution are:

Mount the fixtures at a height that is appropriate for the width of the area to be lit. If the fixtures are too high, the light will be too dim and create dark spots. If the fixtures are too low, the light will be too bright and create glare.

Space the fixtures evenly along the wall or the perimeter of the area to be lit, with a distance that is equal to or less than the mounting height of the fixture. For example, if the fixture is mounted at 10 feet, the distance between the fixtures should be 10 feet or less. This will ensure a uniform and continuous light level along the wall or the perimeter of the area to be lit.

Avoid placing the fixtures near windows or other sources of natural light that may interfere with the artificial light or create glare. If possible, use fixtures that have a shield or a cutoff design, so they don`t emit light above the horizontal plane.

Type V Lighting Distribution

Type V lighting distribution provides a very wide, symmetrical light pattern for fixtures that provide uniform illumination over a large area. The width of the light pattern is about 3.5 times the mounting height of the fixture. For example, if the fixture is mounted at 10 feet, it will cast light up to 35 feet wide on all sides of the fixture.

Type V fixtures are also known as circular or umbrella fixtures. They are ideal for:

Center roadway and intersection mounting
General work or task areas
Large spaces

Type V fixtures are not suitable for:

Narrow walkways
Wide paths
Specific area lighting

Here are some examples of Type V lighting distribution:

To achieve Type V lighting distribution, you can use fixtures that have a circular or square shape, or fixtures that have a rectangular shape with a symmetrical reflector or lens. You can also use fixtures that have an adjustable beam angle, such as LED spotlights or floodlights, and set them to a very wide angle.

Some tips and techniques for using Type V lighting distribution are:

Mount the fixtures at a height that is appropriate for the size of the area to be lit. If the fixtures are too high, the light will be too dim and create dark spots. If the fixtures are too low, the light will be too bright and create glare.

Space the fixtures evenly over the center of the area to be lit, with a distance that is equal to or less than the mounting height of the fixture. For example, if the fixture is mounted at 10 feet, the distance between the fixtures should be 10 feet or less. This will ensure a uniform and consistent light level over the entire area to be lit.

Avoid placing the fixtures near walls or other obstructions that may block the light or create shadows. If possible, use fixtures that have a low profile or a recessed design, so they don`t protrude from the ceiling or the ground.

Conclusion

Lighting distribution is an important factor to consider when designing and installing LED lighting for outdoor spaces. It affects the quality, coverage, and appearance of the illuminated space. Different types of lighting distribution are suitable for different applications, such as walkways, roadways, parking areas, or large spaces.

In this guide, we`ve explained the five main types of lighting distribution patterns, from Type I to Type V, and how to choose the best one for your lighting project. We`ve also provided some tips and techniques to optimize your lighting design and installation.

If you need to purchase lamps in bulk, please contact us.WOSEN is a professional manufacturer and supplier of Led Flood Light, Led Street Light, Led Solar Light, etc. For more information, please visit https://www.wosenled.com/ or contact admin@wosenled.com or WhatsApp +86-13425434349