DarkSky Compliance by Unilamp

Advancing Environmentally Responsible Outdoor Lighting

Outdoor lighting today plays a vital role in preserving the natural night environment while delivering visual comfort and enhancing architectural spaces. DarkSky International provides respected global guidance for responsible lighting, and Unilamp proudly supports these principles.

While several Unilamp luminaires are officially certified by DarkSky International, many more of our products already follow DarkSky-aligned performance standards including controlled uplight, reduced glare, and minimal spill light even without formal registration.

To clearly communicate this performance and enable more informed, environmentally conscious decisions, Unilamp presents DarkSky Compliance, a classification approach referencing the DarkSky environmental zones E0–E4. This framework provides a clear and practical way to understand environmental suitability across our luminaire portfolio.

What Is DarkSky Compliance?

DarkSky Compliance identifies Unilamp luminaires that demonstrate optical performance consistent with DarkSky principles. Products are evaluated based on optical control and BUG rating (Backlight, Uplight, Glare), helping designers understand how luminaires perform in relation to environmental lighting sensitivity.

This approach helps lighting professionals select fixtures that minimize uplight, control glare, and limit unnecessary spill light while maintaining the visual quality required for architectural and landscape lighting applications.

DarkSky Environmental Zones (E0–E4) — Practical Application

E0 – Highest Sensitivity / Highest Control

For observatories, dark-sky reserves, astronomical sites, wildlife protection areas, and sacred or heritage locations.
Requires the most stringent control of uplight, glare, and spill light.

E1 – High Sensitivity / Very High Control

For temples, cultural landmarks, heritage zones, and protected natural landscapes.
Demands tightly focused optics and minimal light intrusion.

E2 – Low Brightness / Residential & Suburban

For residential communities, rural areas, gardens, and low-density neighborhoods.
Lighting should be gently directed, comfortable, and respectful of nearby homes.

E3 – Medium Brightness / Urban Mixed-Use & Commercial

For commercial districts, mixed-use urban areas, streets, and parking environments.
Requires balanced illumination with controlled optical distribution.

E4 – High Brightness / City Centers & Landmarks

For active urban environments, city centers, façades, plazas, and architectural highlights.
Allows higher brightness levels and wider optical performance while maintaining responsible light control.

Zone hierarchy

A luminaire suitable for a stricter zone (e.g., E0 or E1) may be used in any higher-numbered zone. This ensures each lighting solution respects the environmental sensitivity of its application.

The principle is simple:

A luminaire approved for E2 can be used in E3 or E4, but not in stricter environments such as E1 or E0. A product suitable for E0 or E1 can be used anywhere because it meets the highest optical-control requirements.

This hierarchy ensures each fixture respects the environmental sensitivity of its application.

Environmental	Zone Category	ULWR (max%)
E0	Astronomical Observable dark skies, UNESCO starlight reserves, IDA dark sky places	0
E1	Intrinsically dark areas, e.g., “National Parks”, “Areas of Outstanding Natural Beauty” or other “dark landscapes”	0
E2	Low district brightness areas, e.g. Rural or small village locations	2.5
E3	Medium district brightness areas, Small town centres or urban locations	5
E4	High district brightness areas, e.g., Town/city centres with high levels of night-time activity	15

BUG Rating as the Technical Foundation

DarkSky Compliance references BUG ratings to confirm optical precision and environmental compatibility.

For example:

• A B1 U1 G1 luminaire demonstrates strong control of backlight, uplight, and glare
• Such performance may align with multiple environmental zones depending on the project context
• Sensitive zones such as E0 or strict E1 typically require very tight optical control, such as B0 U0 G0

Higher-number zones allow broader optical distributions, while lower-number zones require more restrained optics and minimal light escape.

Why Unilamp Uses the DarkSky Compliance Framework

1. Clear Environmental Alignment

DarkSky Compliance provides a straightforward understanding of how each luminaire aligns with environmental sensitivity from protected natural landscapes to vibrant urban environments.

2. Recognition of Dark Sky Friendly Performance

Whether officially certified or naturally aligned in performance, Unilamp luminaires that support DarkSky principles can be clearly identified through this framework.

3. Commitment to Responsible Lighting

DarkSky Compliance reflects Unilamp’s dedication to environmentally responsible lighting practices, encouraging the appropriate use of each product according to its environmental context.

Download Our DarkSky Compliance Brochure and Luminaire List

For designers, lighting consultants, and project partners who require detailed technical information, we provide dedicated downloadable resources to support accurate planning and specification.

The DarkSky Compliance Brochure includes:

• Full lists of Unilamp luminaires demonstrating DarkSky-aligned performance
• BUG rating references for each model
• Recommended E0–E4 environmental zone applications
• Optical diagrams and key performance notes

To access the complete documentation, please use the links below:

Download the DarkSky Compliance Brochure (PDF)
Download the Luminaire List for DarkSky Compliance (Excel)

Summary

DarkSky Compliance represents Unilamp’s transparent and environmentally responsible approach to supporting DarkSky principles. It provides:

• Clearly defined E0–E4 environmental zones
• Insight into how luminaires meet or exceed DarkSky expectations
• A structured approach ensuring luminaires are used responsibly and appropriately
• Recognition that while some Unilamp products are formally DarkSky certified, many more naturally fulfill DarkSky lighting criteria

Through DarkSky Compliance, Unilamp provides lighting professionals with a clear and environmentally responsible path to selecting the right luminaire for every project.

For more information, visit www.unilamp.co.th or contact online@unilamp.co.th