IESNA Outdoor Light Distribution Types I to V: Contractor & Engineer Selection Guide

Are you ready to transform your outdoor area with brilliant LED lighting? Choosing the right light distribution types is crucial to maximize visibility and create a comfortable environment.

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Choosing Light Distribution Made Easy:

A Guide to Light Spread

Selecting the correct IESNA (Illuminating Engineering Society of North America) light distribution pattern is critical to achieving proper photometrics, minimizing light pollution, and eliminating dark spots across commercial and municipal projects. Whether you are engineering a high-speed roadway, specifying parking lot area lights, or illuminating a secure building perimeter, matching the fixture’s optical pattern to your site layout reduces total fixture counts and lowers project costs.

This guide breaks down IESNA Distribution Types I through V, helping electrical contractors, lighting designers, and facility procurement agents choose the exact optical pattern for their application.

what is Light Distribution Patterns?

The patterns define how light is dispersed from a fixture. In general, it is defined by the point at which 50% of the fixture’s luminous intensity is met. Certainly, you will see these lighting distribution types used regularly in the led lighting, for example, area lighting, roadway lighting, and parking lot lighting, etc.

led lighting distribution types

IESNA Optical Distribution Matrix

Selecting the correct light distribution types for your area lights makes all the difference. 

 

IESNA Type Light Pattern / Lateral Throw Ideal Application Recommended Lightide Fixtures
Type I Narrow, symmetric 2-way lateral throw (60°–180°) Walkways, bike paths, narrow industrial driveways Solar LED Street Lights, Linear Post Tops, Linear led vapor tight
Type II Slightly wider 2-way lateral throw (25°–50° forward) Wider walkways, entrance ramps, low-speed municipal roads Split & All-in-One Solar Street Lights
Type III Asymmetric forward throw (40°–60° forward) Parking lots, roadways, commercial plazas, perimeters LED Area / Shoebox Lights, Outdoor Wall Packs
Type IV Semicircular high forward throw (“Wall” pattern) Building perimeters, security walls, parking lot edges LED Wall Packs, High-Output Area Lights
Type V 360° Circular or Square omnidirectional distribution Center-island parking lots, open intersections, storage yards UFO High Bays, High Mast Floodlights, LED canopy Lights, 
Lightide Guide to light distribution choice

What are the 5 types of lighting distribution patterns?

There are various LED area lights available with different distribution patterns from type I to type V and choosing one from them is a daunting task. To make it easy for you, we have created this guide to help you.

TYPE I

Type 1 light distribution

Pattern Type I is a two-way lateral lighting distribution types having a preferred lateral width of 15 degrees in the cone of maximum candlepower. 

This type of lighting distribution types shines brightly in two opposite directions, making it ideal for wide roads. Imagine the light fixture in the middle of the road, with the light spreading out evenly on both sides. This works best when the light is mounted about as high as the width of the road.

Delivers targeted light along the pathway without wasting light on adjacent unpaved areas.

Type 1 light distribution types

TYPE II

Type 2 light distribution

The preferred lateral width of 25 degrees. Therefore, they are generally applicable to luminaires located at or near the side of relatively narrow roadways. In addition, the width of the roadway does not exceed 1.75 times the designed mounting height.

Wide walkways, as well as other long, narrow lighting. In addition, this type is meant for lighting larger areas and usually is located near the roadside. You’ll find this lighting distribution types mostly on smaller side streets or jogging paths. 

Maximizes pole-to-pole spacing along roadways while maintaining uniform light coverage.

Type 2 light distribution types

TYPE III

Type 3 light distribution

The preferred lateral width of 40 degrees. This type 3 light distribution has a wider illumination area if you make a direct comparison to type 2 LED light distribution. In addition, it has an asymmetric arrangement as well. The ratio between the width of the illumination area and the height of the pole should be less than 2.75.

The Type 3 lighting distribution types need to be placed to the side of the area, allowing the light to project outward and fill the area. Its throw is taller than Type 2 but its side-to-side throw is shorter.

Allows poles located on the perimeter or sides of a roadway to project light deep across multiple traffic lanes or parking bays.

Type 3 light distribution types

TYPE IV

Type 4 light distribution

The same intensity at angles from 90 degrees to 270 degrees. And it has a preferred lateral width of 60 degrees. Intended for side-of-road mounting on wide roadways width does not exceed 3.7 times the mounting height.

The type 4 light distribution types shine in a half circle, perfect for mounting on walls or the edges of parking lots and businesses. Think of it like a spotlight that spreads out wide on one side.

Keeps 100% of the light output on your property while strictly adhering to municipal dark-sky and light-trespass ordinances.

Type 4 light distribution types

TYPE V

Type 5 light distribution

Produces a circular 360°distribution that has equal light distribution at all positions. And this light distribution has a circular symmetry of foot-candles that is essentially the same at all viewing angles.

This type 5 light distribution shines out in all directions, making it perfect for lighting up the middle of roads, parks, or intersections. Imagine standing in the center and having light all around you.

Provides uniform, omnidirectional illumination in every direction from a single central mounting location.

Type 5 light distribution types

TYPE VS

Type 5S light distribution

Produces a square 360° distribution that has the same intensity at all angles. And the light distribution types have a square symmetry of candlepower that is essentially the same at all lateral angles. 

It is intended for luminaire mounting at or near the center of roadways, center islands of the parkway, and intersections. So it is used where the light pattern needs a more defined edge.

Provides uniform, omnidirectional illumination in every direction from a single central mounting location.

Type VS light distribution types

Let us guide you through the process of selecting the perfect lighting distribution types for your LED area lighting needs!

Now that you’ve met the light performers, how do you pick the right one? Here are five easy questions to ask yourself:

Think about how big your space is. Bigger areas need lights that spread light out wide, while smaller spaces do better with more focused beams. This will help you get the right amount of light everywhere.

Do you just want some general light, or do you need something bright for working on tasks? Different light spreads work better for different things. Wide beams are good for even light everywhere, while narrow beams are great for spotlighting specific areas. Check out the light spread options and the light fixtures themselves to see what works best for you.

Where you put the lights affects how the light spreads. Higher lights need wider beams to reach everything, while lower lights work better with narrower beams so they don’t create glare.

For outdoor lights, consider how rain, wind, and other weather might affect the light.

There are many different LED light distribution types, like Type I, II, III, IV, and V. Each one spreads light in a different way, so there’s a perfect fit for your needs. Do some research to see which type works best for you.
The right light makes all the difference!

Considering these quick tips will help you find the perfect LED area lights for your space. They’ll brighten things up and make it feel more welcoming. Need a hand? We’re happy to help! Let’s make your space shine with the perfect LED lights!

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Custom Optical Engineering & Photometric Support

At Lightide, we manufacture high-efficiency precision optics using UV-stabilized optical polycarbonate and glass lenses.

Need to confirm photometric performance before placing a bulk order? Our engineering team provides custom Dialux lighting simulation layouts and complete downloadable .IES files for all our commercial outdoor fixtures, ensuring your project meets strict foot-candle and uniformity requirements prior to installation.

High-Capacity Manufacturing & Global Export Logistics

We protect your project budget through optimized container packaging:

  • Maximized Container Density: Our fixture packaging is engineered to maximize unit density inside 40′ HQ containers, significantly reducing per-unit ocean freight costs.

  • Frictionless Customs Clearance: All specialized export shipments strictly comply with mandatory Damage Package Certification standards, guaranteeing zero-delay clearance through China customs and smooth border passage.

 

NEMA Beam Angle

How to Choose Suitable NEMA distribution for LED Outdoor lighting?

Floodlights and sports lights often use a system called NEMA to show how wide the beam spreads. Imagine the light spreading out like a circle. NEMA tells you how wide that circle gets before the light gets too dim (around 10% of its brightest). Knowing this will help you pick lights that light up your space just the way you want.

Get Expert Photometric Support & Bulk FOB Pricing

Need assistance selecting the right IESNA optical distribution for your upcoming project? Looking for a competitive Proforma Invoice (PI) on a container-load order?

Contact our sales engineering team via email or connect with us directly on WeChat ( +86 185 8822 3315) for immediate technical support, .IES file requests, and real-time FOB pricing.

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