Posted by Doug Root on 14th Sep 2015

What are Light Distribution Types?

outdoor security light on brick wall

There are a lot of important factors to look at when choosing the right light fixture. Lumens per watt, fixture type, warranties, and color temperatures are all super important, but how about light distribution?

One of the more critical things to look at is the type of light distribution from the fixture itself. If you know how to properly figure a layout based on using the right fixture and the correct distribution of light, you can lower fixture counts and get a better lit project. You can have a great fixture, but if you’re not putting light where you want, it's only as good as the layout!

Different Types of Light Distribution Patterns

Light distribution is basically the projected pattern of light that a  fixture will disperse onto a surface. Let’s look at light distribution types in relation to inside the building and outside the building.

  • Indoor beam spread patterns
  • Outdoor light distribution patterns

Indoor Lighting

Indoor fixtures and bulbs typically used beam spreads like a  30-degree flood, 270-degree omnidirectional & 8-degree spot. The beam spread that you use is the determining factor in how far the light will travel onto a surface. If you have a wide beam of 40 degrees and you want it to pin spot on a sign 20 feet away, you are barking up the wrong tree. However, if you use an 8-degree spot, that sign will look great!

parking lot lights at night

Outdoor Lighting

Outdoor light fixtures use light distribution patterns. The patterns define how light is dispersed from a fixture and is defined by the point at which 50% of the fixture's luminous intensity is met. You will see these distributions used regularly in parking lot lights, area lighting, floodlighting & roadway lighting. While there are other symmetrical and asymmetrical light distribution types, the industry has identified 5 main types of light distribution patterns:

  • Type I

    Type I distribution is popular for lighting walkways, paths, and sidewalks. We use this type of lighting in the middle of a pathway and it is great for narrow pathways.

  • Type II

    Type II is commonly used on larger walkways and in roadway lighting as it is good for a larger but still narrow area. You will see this type used on side streets or jogging paths.

  • Type III

    Type III is very commonly used in roadway lighting as it gives a bit more coverage further from the point source outward. Type III lighting needs to be placed to the side of the area, allowing the light to project outward and fill the area.

  • Type IV

    This light distribution produces a semicircular light that should be used on the sides of buildings and walls. This type does a great job lighting up a parking area perimeter.

  • Type V

    This is the widest distribution pattern and is excellent for illuminating the inside portions of a parking lot or a 4-way intersection.

With this basic knowledge, selecting the right light distribution type for your security lights or parking lot lights becomes easier.

Shop Quality Bulbs and Fixtures

If you’re looking to have a professionally laid out lighting package, you have come to the right place. We have the capability to layout your parking lot or area using satellite maps and overlaying the fixtures and types to show you where the light will be distributed! Our  ALB Energy Solutions team is here to help you.

We offer turnkey lighting solutions, from selecting the right light distribution type to fixture layout and complete installation. Give us a call at 770-492-5086, send us an email at  [email protected] or fill out our contact form here. Let Atlanta Light Bulbs be your lighting expert!