Street Lighting

Types of Street Lighting and Their Applications

Within the category of street lighting, a wide range of lamps is available, each designed for specific applications and conditions. The choice for a particular type depends on factors such as the width of the road, the desired light distribution, and the presence of pedestrians or cyclists.

• LED street lanterns: These fixtures are the modern standard. They are compact, efficient, and offer a long lifespan. They often include optics that direct the light specifically, which prevents waste. They are available in various light outputs and light colors.
• LED retrofit lamps: For existing fixtures with traditional light sources, such as gas-discharge lamps, there are LED retrofit lamps. These lamps fit directly into the existing socket, making the transition to LED easy without replacing the entire fixture. They provide a quick way to save energy and improve light quality.
• High-pressure sodium lamps (SON/NAV): Although in many new installations they have been replaced by LED, these lamps are still commonly seen. They emit a characteristic orange-yellow glow and are mainly used for functional road lighting.
• Metal halide lamps (CDM/HQI): These lamps produce a whiter light than sodium lamps and are used in places where better color rendering is desirable, such as in city centers or on business estates.

Important Technical Specifications of Street Lighting

When selecting and installing street lighting, various technical features are important to ensure safe and sustainable operation. Below, the most common and relevant specifications that influence the performance and lifespan of the lamps are explained.

IP Rating: Protection Against External Influences

The IP rating (Ingress Protection) indicates the degree of protection against solid objects (such as dust) and water. For street lighting, a high IP rating is crucial, given the exposure to all weather conditions. Most street lighting is IP65 or higher.

Lumen and Watt: The Right Balance in Brightness and Consumption

The light output of a street lamp is expressed in Lumens (lm), indicating how much light the lamp actually produces. The higher the number of Lumens, the brighter the lamp. The wattage (W) indicates the energy consumption. For LED lighting, lower wattage can produce the same or more Lumens than a traditional lamp with higher wattage, which leads to significant energy savings.

• Public roads: For main roads, high light output is often required, ranging from 8,000 to 25,000 Lumens per fixture, depending on the road category.
• Residential areas and cycle paths: Here, a lower Lumen value, such as 2,000 to 8,000 Lumens, is usually sufficient to create a pleasant and safe environment without over-illumination.

Light Color (Kelvin) and Color Rendering (CRI)

The light color, expressed in Kelvin (K), affects the perception of the environment and ambiance. The Color Rendering Index (CRI) indicates how natural colors appear under the light of the lamp.

• 2700K - 3000K (Warm white): This light color is increasingly being used in residential areas or historic city centers to create a warmer, less harsh atmosphere that causes less light pollution and is perceived as more pleasant by residents.
• 4000K (Neutral white): This is the most common light color for main roads, commercial sites, and industrial zones. It provides bright, functional lighting that enhances the visibility of objects and traffic signs.
• CRI value: For street lighting, a CRI of 70-80 is usually sufficient. For locations where color recognition is especially important, such as shopping streets or intersections, a higher CRI may be desirable.

IK Rating: Protection Against Vandalism

The IK rating indicates the degree of impact resistance, which measures how well a fixture resists external mechanical influences, such as vandalism. Especially in public spaces, a higher IK value (for example, IK08 or IK10) is recommended to extend the lifespan of the installation and reduce maintenance costs.

Installation Considerations for Street Lighting Lamps

Attention to detail is required when installing street lighting. These are generally complex installations that require the expertise of a qualified professional.

A frequently asked question is how an existing traditional lamp in a fixture can be replaced by an LED variant. This depends on the type of LED retrofit lamp. Some LED lamps are "plug-and-play" and only require swapping the lamp and possibly a starter. Other LED lamps, which work directly on mains voltage, require the removal of the ballast from the fixture. Always consult the manufacturer's manual.

For optimal results, the correct positioning of the lamp in the fixture affects the light distribution on the road. Sometimes adjustable optics or specific mounting options are needed for this purpose.

Long-term Benefits of Modern Street Lighting

Investing in modern street lighting, particularly LED, yields a range of benefits that go beyond simply providing light. These benefits affect operational costs, the environment, and overall safety and livability.

• Lower energy consumption: LED lamps consume significantly less energy than traditional light sources. This results in substantial savings on the energy bills of municipalities and business owners.
• Reduced maintenance frequency: The long lifespan of LED lamps (up to 100,000 operating hours) means less frequent replacement. This reduces labor costs and traffic disruption due to maintenance work.
• Improved light quality: LED lighting provides clear and uniform illumination, increasing visibility for road users and thereby promoting traffic safety. The ability to use specific optics ensures light is directed where it is needed, without unnecessary stray light.
• Less light pollution: Thanks to directed light beams and the option for warmer light colors, light pollution (light shining unnecessarily into the sky) can be minimized, contributing to better visibility of the night sky and less disturbance to nature.
• Smart control options: Many modern street lighting systems can be integrated into smart management systems. This allows for remote dimming, switching on and off, or adjustment according to traffic density or weather conditions, further contributing to energy savings and flexibility.

Upgrading to LED street lighting is an important step for municipalities and companies aiming for a sustainable, safe, and cost-effective public space. Choosing the right lamps, based on solid knowledge of technical specifications, provides the foundation for an efficient and functional lighting system. For complex projects and extensive advice, collaboration with specialized parties who have experience with public lighting projects is often recommended.