#area light technology · #glare-free · #LED light distribution · #optical design · #outdoor lighting performance · #Type III · IESNA standard ·01 de diciembre, 2025

What do the Type III/IV/V light distribution curves of ZC Lighting LED area lights mean?

When selecting LED area lights for parking lots, communities, or commercial spaces, one technical term that often confuses buyers is “light distribution curve.” This curve defines how light spreads from a fixture—directly impacting illumination uniformity, coverage efficiency, and whether the light meets your space’s unique needs. ZC Lighting LED Area Lights offer three common distribution types: Type III, Type IV, and Type V. In this blog, we’ll break down what each type means, their key characteristics, and which scenarios they’re best suited for—helping you make an informed choice for your lighting project.

First: What Is a Light Distribution Curve?

A light distribution curve is a graphical representation of how a lighting fixture emits light across a horizontal plane (measured in degrees from the center of the fixture). It shows the intensity of light (in candelas) at different angles, revealing whether the light spreads narrowly, widely, or in a specific pattern. For LED area lights, these curves are standardized by organizations like the IESNA (Illuminating Engineering Society), which categorizes distributions into Types I-V based on their spread and intensity patterns.

Choosing the right curve type ensures you’re not wasting light (e.g., shining it onto adjacent properties) or creating dark spots—saving energy and improving lighting quality.

1. Type III Light Distribution: Ideal for Narrow to Medium Spaces

Type III distribution is characterized by a moderate spread of light, with the highest intensity concentrated at 25°-40° from the fixture’s center. It’s designed to照亮 areas where the fixture is mounted near the edge of a space, such as along building walls or narrow parking lanes.

Key Characteristics of ZC Lighting Type III LED Area Lights

Beam Spread: 90°-120° horizontal spread—wider than Type I/II but narrower than Type IV/V.
Intensity Pattern: Peak intensity at 30°-35°, with light gradually tapering off beyond 45°.
Mounting Height: Best suited for 12-20 feet (3.6-6 meters) heights—common in low-rise community areas or narrow parking lots.

Best Applications for Type III

Narrow Parking Lots: Lots with 1-2 lanes where fixtures are mounted along the perimeter (e.g., strip mall parking with buildings on one side).
Community Sidewalks & Walkways: Paths adjacent to buildings, where light needs to cover the walkway without spilling excessively onto lawns.
Building Perimeters: Illuminating loading docks or entryways where the fixture is mounted on the building wall.

Example: A ZC Lighting 100W Type III LED Area Light (120° beam) mounted at 15 feet along a narrow parking lot will evenly cover a 15-20 foot wide lane, with minimal light waste on the adjacent building or street.

2. Type IV Light Distribution: Perfect for Wide Open Areas

Type IV distribution features a wider, more symmetrical spread than Type III, with peak intensity at 40°-60° from the center. It’s engineered to cover large, open spaces where fixtures are mounted in the middle of the area—ensuring uniform light across a broad footprint.

Key Characteristics of ZC Lighting Type IV LED Area Lights

Beam Spread: 120°-150° horizontal spread—ideal for covering expansive areas.
Intensity Pattern: Peak intensity at 45°-50°, with consistent light distribution up to 70°—minimizing shadow gaps between fixtures.
Mounting Height: Optimal for 15-25 feet (4.5-7.6 meters) heights—common in medium to large parking lots and community parks.

Best Applications for Type IV

Medium-to-Large Parking Lots: Open lots with 3+ lanes (e.g., grocery store or office park parking), where fixtures are pole-mounted in rows.
Community Parks & Playgrounds: Wide open spaces where uniform illumination is needed for safety (e.g., baseball fields, picnic areas).
Industrial Yards: Open storage areas or loading zones that require broad coverage without dark spots.

Case Study: A retail plaza in Chicago installed ZC Lighting 120W Type IV LED Area Lights (150° beam) at 20-foot poles across its 8,000 sq. ft. parking lot. The Type IV distribution ensured consistent 70 lux illumination across the entire lot, with no dark spots between poles—improving shopper safety and satisfaction.

3. Type V Light Distribution: Symmetrical Coverage for Central Mounting

Type V is the most symmetrical distribution, with light spreading evenly in a 360° pattern (or near-360°) from the fixture. Peak intensity is at 60°-80° from the center, making it ideal for fixtures mounted in the absolute center of a space.

Key Characteristics of ZC Lighting Type V LED Area Lights

Beam Spread: 150°-180° horizontal spread—near-circular coverage.
Intensity Pattern: Uniform intensity across all angles (360°), with peak brightness at 70°-75°—creating a “circle of light” on the ground.
Mounting Height: Best for 20-30 feet (6-9 meters) heights—suited for large, circular or square spaces.

Best Applications for Type V

Large Circular Parking Lots: Round lots (e.g., hotel or stadium parking) where poles are placed in the center.
Community Squares & Plazas: Open gathering spaces with a central focal point (e.g., a fountain or monument), where light needs to spread evenly in all directions.
Industrial Warehouses with Central Aisles: Large indoor spaces where fixtures are mounted along the center to cover both sides of the aisle.

Pro Tip: ZC Lighting’s Type V LED Area Lights are often used in pairs for rectangular spaces—mounted along the centerline to create overlapping circular coverage, ensuring uniformity.

How to Choose Between Type III/IV/V for Your Project

Follow these steps to select the right distribution curve for your ZC Lighting LED Area Lights:

Map Your Space Shape & Size: Narrow/linear spaces (Type III); wide/open rectangular spaces (Type IV); circular/square spaces with central mounting (Type V).
Determine Mounting Location: Fixtures near edges/walls (Type III); fixtures in rows/middle of open areas (Type IV); fixtures in the absolute center (Type V).
Check Mounting Height: Lower heights (12-20ft = Type III); medium heights (15-25ft = Type IV); higher heights (20-30ft = Type V).
Calculate Coverage Needs: Use ZC’s lighting design tool to input your space dimensions and mounting height—it will recommend the optimal distribution type and fixture quantity.

Conclusion: The Right Distribution Curve = Perfect Illumination

Understanding Type III, IV, and V light distribution curves is key to getting the most out of your ZC Lighting LED Area Lights. Each type is engineered for specific space shapes, mounting locations, and coverage needs—ensuring you get uniform, efficient illumination without waste.

Whether you’re lighting a narrow sidewalk, a sprawling parking lot, or a community plaza, ZC Lighting has a Type III, IV, or V LED area light that fits. Contact ZC Lighting’s technical team today for a free distribution curve consultation—they’ll help you select the perfect model to transform your space with bright, balanced light.