Does Street Light Poles Influence Lighting Output?
Everyone has walked in the dark several times in his or her lives. Do you remember how frightening it was? Instances like these happen around the world, barring some well-lit smart cities. However, people in India still face the blacked-out streets on a regular basis. It is a safety concern and must be addressed by the authorities and planners.
Lighting is a necessity, and its implications in the modern society are well-known. Cities around the world are transforming and are adopting efficient ways to light their streets. LEDs are bringing the change, and are revolutionizing the lighting industry in significant ways. The successful use of LEDs in smart cities is well documented. Highways, Streets, Parking Lots, and all key public places are seeing the shift to LEDs for their numerous advantages.
Street lights must be refurbished with LEDs to make the roads safer and provide adequate lighting during the night. LED street lights are already transforming the lighting sphere, and there are several reasons why this technology must be used in street lighting. Apart from choosing LED lights, it is also important to select proper street light poles to ensure the luminaires deliver maximum performance and the projected area is effectively lit.
The Role of Street Light Poles
Everyone talks about the importance of lighting on streets and highways. However, the part of light poles is equally important. Street light poles are the backbone of street lighting, and their use case extends from providing adequate lighting to the beautification of urban spaces. Today, designers choose light poles that blend with the modern city landscapes to provide a more homogenous and distinguished look.
To maximize performance and output, LED luminaires must be installed correctly on the light poles. Light poles are engineered to support single or multiple luminaires, and some of them even have provisions for pennants, banners, and signs as such. The primary function of light poles is to provide adequate light spread on the roads. They must also be able to resist the physical forces such as the wind load, weight of the luminaire and the weather.
Factors Affecting Pole Selection and Lighting Output
There are several factors a technician figures out to determine the pole requirements when installing street light poles.
The height at which a luminaire is mounted measured from the base of the pole. This height is not the length of the pole and is usually determined by the authorities after a lighting survey. This survey identifies the requirement of the number of poles, the type of luminaires and quantity of luminaires per pole. The optimum mounting height should be calculated by considering the light output and distribution of the luminaires, and the geometry of the installation. For powerful luminaires, the mounting height should be more to avoid excessive glare.
Spacing – It is the distance measured along the center line of the road between two successive luminaires. The space height ratio should be greater than 3 to preserve longitudinal uniformity.
Outreach – It is the horizontal distance between the center of the column and center of the luminaire. Aesthetical considerations determine the outreach.
Overhang – The horizontal distance between the center of the luminaire mounted on a bracket and the adjacent edge of a road. Overhang should not exceed 1/4th of the mounting height to avoid reduced visibility of curbs, footpaths, and obstacles.
Simply put, drag coefficient (Cd) is the resistance created by an object in a fluid environment. Streamlined objects have a lower Cd than blunt or flat sided objects. It is a principal factor because the OTM (Over-turning bending moment) depends on the Drag Coefficient. OTM is the bending moment (force times distance) caused by the wind force acting on the poles and lighting fixtures, which tend to topple the pole.
Effective Projected Area
Luminaires are rated in EPA which refers to the apparent wind profile of a fixture or an object based on its geometric shape.
Pole Geometry, Shape, and Style
Pole Geometry is the dimensional and physical shape of the pole. The most common forms used for poles are round a square with cross-sections. Several commercial lighting manufacturers design tapered poles. Proper pole height and spacing provides uniform light distribution which improves security and safety.
- Swaged Poles – Swaging is a forging process where the dimensions of an object are altered using dies by applying force. Swaged Poles are the most popular street light poles. Manufacturers like Wipro provide an entire range of Swaged Poles with specifications confirming to IS2712: Part II.
- Decorative Poles – These poles are the favorite choice of designers and urban planners. Most manufacturers offer a wide variety of street light poles that can be customized to synchronize with the landscape.
- Octagonal Poles – Modern design and an amalgamation of sleek, elegant, and aesthetic design. Octagonal Poles require minimal maintenance and are an ideal choice for urban beautification projects.
High Mast Lighting is a tall pole where luminaires are attached to the top which illuminates a vast amount of ground area. The high mast pole is usually rated at 30m and contains four to eight luminaires in a ring. It can also hold up to 12 lights in rarer circumstances. High Mast Lighting is currently the most efficient and cost-effective way of illuminating large outdoor areas like highways, parking lots, toll plazas and road junctions.
The standard pole materials are aluminum, fiberglass, and steel, with steel being the most common. They are also made from concrete, and cast iron. However, these materials are rarely used.
Certain auxiliary equipment such as cameras, banners, pennants is also installed on lighting poles.
Type of Luminaire
LEDs are the future, and most cities are refurbishing to these luminaires for their advantages. However, the wattage and luminaire height must be calculated depending on the effective projected area. Minimizing blinding glare for pedestrians and drivers must be considered. The choice of luminaires must meet community preferences and are based on the streets and surrounding neighborhoods. In addition to optimum light output, street light fixtures must be sturdy, reliable, and weather resistant. Luminaires designed with an aluminum pressure die-cast parts like the Skyline LED by Wipro offer best in class efficiency and high energy saving. The toughened glass with silicon gaskets ensures IP 66 protection and are suitable for poles with a diameter of up to 60mm.
Street lighting is a necessity and critical factor for several reasons. Lighting the streets improves safety and increases security in areas like doorways, bus stops, and isolated thoroughfares. It aids in geographical orientation and highlights the important landmarks. The right commercial lighting options are crucial, and street light poles play an equally significant role. The choice of light poles will determine how well the completed outdoor area looks.