What is the beam spreading in lighting? Light beam spread is a crucial consideration for lighting design and installation. Understanding how to measure and control light beam spread can significantly impact the effectiveness of your lighting system. This guide will explore the basics of light beam spread, including how it is measured and what factors influence it. By the end of this guide, you will have a solid understanding of optimizing light spread for your specific lighting needs.
How to Measure Beam Spread Correctly?
To calculate the beam spread of a light source from a specific distance, use the light beam spread (beam angle) formula: Angle of Beam x .018 x Distance = Beam Spread. For instance, if you need to find out the beam spread of a 120-degree floodlight from a 15-foot distance, you can use the formula: 120 x .018 x 15 = 32.4.
The Beam Spread Chart
The table in this guide can be used to easily determine beam spread.
|
Degree of Light |
At 5 Feet |
At 10 Feet |
At 15 Feet |
At 20 Feet |
|
10 |
0.9 feet |
1.8 feet |
2.7 feet |
3.6 feet |
|
15 |
1.35 feet |
2.7 feet |
4.05 feet |
5.4 feet |
|
20 |
1.8 feet |
3.6 feet |
5.4 feet |
7.2 feet |
|
25 |
2.25 feet |
4.5 feet |
6.75 feet |
9 feet |
|
40 |
3.6 feet |
7.2 feet |
10.8 feet |
14.4 feet |
|
45 |
4.05 feet |
8.1 feet |
12.15 feet |
16.2 feet |
|
60 |
5.4 feet |
10.8 feet |
16.2 feet |
21.6 feet |
|
90 |
8.1 feet |
16.2 feet |
24.3 feet |
32.4 feet |
|
120 |
10.8 feet |
21.6 feet |
32.4 feet |
43.2 feet |
Standard Beam Spread
Narrow Spot 2 × 2
The narrow spot distribution is well-suited for applications requiring a tight beam or for those with longer distances, like flagpoles or tall trees.
Narrow Flood 4 x 4
Narrow flood distribution is perfect for accenting sculptures or landscape and facade lighting with far setbacks. It produces a concentrated beam that is both tight and symmetrical.
Horizontal Flood 5 x 3
Horizontal flood lighting is a type of light beam spread that has a wide horizontal coverage with a narrow vertical concentration. It is particularly useful for lighting applications that require a wide horizontal coverage with a shorter setback and is ideal for grazing and accentuating architecture.
Vertical Flood 3 x 5
Vertical flood lighting is ideal for tall facades and signs with limited setbacks. This lighting technique provides a tall and concentrated distribution of light.
Medium Flood 5 x 5
Medium flood is suitable for facades, signs, and general exterior applications that require a wider and more uniform light pattern with a medium setback. It is also ideal for use under canopies.
Wide Flood 6 × 6
Wide flood distribution is suitable for applications that require a shorter setback and provide a large and uniform light pattern. It can be used for signs, large facades, and broad areas of foliage. Additionally, it is ideal for pole-mounted applications in general areas.
Which One to Choose: Spot Beam or Flood?
Spot
Spotlights and small landscape floods, also known as spot floods, are commonly used to accent specific features and small areas because they allow for precise direction of the light. Spotlights typically have narrow beams of 25 degrees or less, which concentrate the light in a specific area. This makes them ideal for illuminating tall trees, flag poles, statues, and other elements from a distance. Narrow beam spotlights also have a lower percentage of beam lumens falling outside the area to be lit compared to wide beam flood lights. This creates dramatic light and shadow effects that can be visually appealing in outdoor settings. Additionally, small outdoor spots can be used to contain light to small outdoor seating areas without worrying about causing light pollution or disturbing neighbors.
Flood
Flood lights are a popular lighting option for various outdoor spaces due to their broad beam spread and versatility. They can be used to illuminate large areas, such as parking lots, driveways, and patios, making them ideal for outdoor gatherings or events.
It is important to note that while the beam spread from a flood light is wider than a spotlight, the light does not reach as far due to the smaller angle of light. Floodlights typically have a beam spread of more than 45 degrees and up to 120 degrees. However, some lights marketed as floods may have a beam as narrow as 25 degrees, so it is important to consider your specific lighting needs when choosing a flood light.
If you require a narrow beam angle, spotlights may be a better option. Spotlights are designed to emit a narrow beam of light with a beam spread of less than 45 degrees, making them ideal for highlighting specific areas or objects. With their focused beam, spotlights can be used to create dramatic lighting effects or draw attention to specific features of your outdoor space. Overall, both floodlights and spotlights offer unique benefits and can be used in various outdoor lighting applications.
Importance of Mounting Height for the Proper Light Spread
The effectiveness of a lamp's illumination is significantly impacted by its mounting height. Since LEDs naturally direct light in a cone, the beam will determine the area that will be lit up.
When determining the ideal LED beam spread chart for your lighting fixture, it is important to consider the distance between the fixture and the area you want to illuminate. For shorter distances, a wider flood beam is recommended, as a long-range narrow beam is not necessary. However, when lighting a specific target at a further distance, a more narrow and farther-reaching beam is ideal.
To prevent overlapping, consider the distance between light sources and the beam's radius when using multiple fixtures. If you plan to use wider beam fixtures to create ambiance, ensure the beam spread diameter (radius x 2) is equal to or greater than the distance between the fixtures.
Manufacturers often include photometric reports on their product data sheets, which can help you determine if a lighting fixture is suitable for your intended application. These reports provide valuable information that can assist in selecting the right fixture for your needs.
