Note : This story was published in CSIR-NISCAIR’s prestigious magazine ‘ Science Reporter’ in October 2023.
Street Lights : Smart Solutions for Energy-Efficient Lighting in India
Streetlights rarely catch our attention until and unless they are flickering or not working. We have our sight all around but never goes up to the streetlights lighting our path ahead. Even if we see the streetlights, they appear like some dead structures hanging in the middle and sides of the road.
India is a country that is home to a diverse range of cultures, traditions and customs. It is a land of contrasts, where the modern and the traditional coexist in harmony. One of the visible signs of this contrast is the street light designs that one can see across the length and breadth of the country.
The street light designs in India vary from region to region. One can see the traditional lantern-style designs in rural areas, while in urban areas, the designs are modern and sleek. The street lights in rural areas of India are made of metal or bamboo and are designed to look like lanterns. Some cities have even gone the extra mile to make their street lights eco-friendly by using solar panels.
India is a country that is rapidly developing, and the government is taking steps to modernize the infrastructure. Street light designs are a crucial part of this infrastructure. They are not only essential for public safety but also for beautifying the surroundings. One of the most striking examples of street light designs in India is in the city of Jaipur. Known as the ‘Pink City,’ Jaipur is famous for its beautifully designed buildings, and the street lights are no exception. The street lights in Jaipur are designed to complement the architecture of the city’s buildings, with intricate and ornate designs.
Another city that stands out for its street light designs is Bangalore. The street lights in Bangalore are modern and sleek, and many of them use LED technology. The city has also installed solar-powered street lights in some areas, which not only saves electricity but also helps to reduce carbon emissions.
Types of Streetlights
Streetlights play a vital role in maintaining the safety and security of public spaces in India. In recent years, advancements in technology and urban planning have led to significant improvements in the design of streetlights. We must explore the various aspects of streetlight design in India, including the types of streetlights, their placement, and the factors that influence their design.
In India, there are several types of streetlights that are commonly used. These include:
1. High-Pressure Sodium (HPS) Lamps: These lamps emit a warm, yellowish light and are commonly used on arterial roads, highways and expressways.
2. Light Emitting Diode (LED) Lamps: LED lamps are energy-efficient and have a longer lifespan than High-Pressure Sodium lamps. They are used in residential areas, parks, and pedestrian walkways.
3. Metal Halide Lamps: These lamps emit a bright white light and are used in commercial areas and stadiums.
Placement of Streetlights
The placement of streetlights is crucial to ensure sufficient lighting for public safety. In India, streetlights are placed based on various factors such as:
1. Traffic volumes: Streetlights are installed at regular intervals on arterials and highways to ensure better visibility for drivers.
2. Pedestrian traffic: In areas with high pedestrian traffic, streetlights are installed at lower heights to provide better illumination on footpaths.
3. Environmental factors: In areas with high wind speeds, streetlights are installed closer to the ground to prevent damage.
Box item 1
A busy road will need bright and wide-ranging lights to ensure the highest visibility for cars on the road.
Box item 2
Residential areas or small streets may require warm light that is not too bright to avoid disturbing residents.
Box item 3
Lights in parks or gardens may have a softer and more elegant design that blends well with the surrounding area.
Design Factors
Several design factors influence the design of streetlights in India, including:
1. Power supply: The power supply for streetlights in India is typically 230V AC, 50Hz.
2. Light intensity: The intensity of light provided by streetlights varies depending on the location and purpose of the lighting.
3. Mounting height: The mounting height of streetlights varies based on the location and type of streetlight used.
Who designs the lights ?
Lights are typically designed by professional engineers or lighting designers who have expertise in electrical engineering and lighting technology. These professionals work with local government agencies and contractors to determine the appropriate lighting requirements for a given location, taking into account factors such as traffic flow, safety, and aesthetics. The design process may also involve consideration of energy efficiency and sustainability in order to reduce the environmental impact of the street lights. Additionally, manufacturers may also have in-house engineering teams who design and develop street lights for production.
Anil Kumar Choudhary, Head Operations (Lighting) at EESL explains that “For installation of new lights everything is decided by EESL. Overall standard design requirements for the lights is given by EESL along with the specifications and lux level on the ground is given by EESL. But the lights and fixtures are manufactured by the selected manufacturing companies. Our specifications are way ahead then what is prevailing in the market because we are bringing in all the time better product than what is available.
Box Item 4
The design of a street lighting system must be appropriate for the site and should provide the level of illumination (lux) and uniformity of light specified in the Indian Standard (BIS, 1981).
How streetlights are designed in India ?
Streetlight design in India has evolved significantly over the years, with a focus on safety and energy efficiency. By understanding the various types of streetlights, placement considerations, and design factors, we can ensure that our streets are well-lit and safe for all.
In India, streetlights have come a long way and have undergone a significant transformation in the past couple of decades. The country has been proactive in adopting advanced lighting technologies and has made considerable advancements in the design of streetlights. The design of streetlights in India takes into account a variety of factors, including the location of the street, the cost-effectiveness of the solution and the environmental impact. Streetlights are designed to enhance visibility at night, reduce accidents, and provide for a safe and well-lit environment.
One of the most significant advancements in streetlight design in India is the introduction of LED lighting technology. LEDs are highly energy-efficient and cost-effective when compared to conventional lighting. The use of LED lights in streetlights has resulted in a significant reduction in energy consumption and has helped in minimizing the carbon footprint. This has made LED lighting a popular option for public lighting systems throughout India.
Moreover, the Indian government has been working to make streetlights more environmentally friendly. Solar-powered streetlights are being installed in various regions across the country. These streetlights work using solar panels that collect energy during the day, store it in batteries and use it to power the LED lights at night. This technology reduces the dependency of streetlights on electricity and lowers the carbon footprint of the country.
Furthermore, the design of Indian streetlights is also focused on durability and low maintenance. The lights are housed in sturdy, weather-resistant enclosures that protect them from the elements and prevent damage due to vandalism or accidents. Additionally, the components used in the lights are of high quality and require little maintenance, reducing the need for frequent repairs and replacements.
Box Item 5
Lighting components can be grouped based on their functions. They are generally described as the structural systems, electrical systems, and optical systems. The items covered include :
Structural
• Poles
Optical
Electrical
• Lamps
• Ballasts
- Service Cabinets (fuse box)
Factors considered for streetlights
Choosing the right type of streetlight involves several factors that need to be considered. Some of these factors include height, distance, bulb, angle, and design. An optimal balance of these factors is crucial for road safety and maintaining the overall illumination of the city. It is essential to choose streetlights that provide visibility while not causing light pollution, and that are aesthetically pleasing to the surroundings.
- The first factor to consider is the height of the streetlight. A streetlight that is too short would not provide enough illumination and risk accidents at nighttime. On the other hand, a streetlight that is too tall could be expensive to install and maintain. Therefore, a height that is optimal for the street and its immediate surroundings should be selected to ensure sufficient lighting coverage while also avoiding interfering with any tall buildings or trees nearby.
- The distance between each streetlight is also a critical factor to consider. The distance should be appropriate as too much space between them will leave dark spots and thereby reducing visibility for drivers and pedestrians. Conversely, too little space can mean that the streetlights become overbearing, resulting in light pollution, which may disrupt the natural habitat of birds and animals.
- The type of bulb used in streetlights is also an essential factor. Today there are many bulbs that can be used, like halogen, LED, fluorescent, and high-intensity discharge lamps. Each bulb has its own lighting capacity and energy efficiency. Some may be more suitable for certain locations or situations, while others might be too harsh or bright.
- Another crucial factor is the angle of the streetlight. An incorrect angle can affect the amount of light distributed, making some areas too dark or too bright, resulting in glare that can be harmful to drivers. Therefore, choosing the correct angle is crucial for proper lighting distribution.
- Finally, the design of the streetlight is also an essential factor to consider. The design should be in line with the overall aesthetic of the city or town. It is important that the streetlight meets the requirements of functionality and style.
National Lighting Code (NLC)
The National Lighting Code (NLC) is a document that sets out the minimum standards for lighting design, installation and maintenance in India. The code was developed by the Bureau of Indian Standards (BIS) in collaboration with the Indian Society of Lighting Engineers (ISLE).
The NLC provides guidelines to ensure that lighting is provided in a manner that is safe, effective and energy-efficient. The code covers indoor and outdoor lighting systems, including street lighting, lighting in parks and public spaces, and lighting in commercial and residential buildings.
One of the key objectives of the code is to ensure that lighting is energy-efficient, which helps to reduce energy consumption and greenhouse gas emissions. The code recommends the use of energy-efficient lighting technologies such as LED (light-emitting diode) and CFL (compact fluorescent lamp) bulbs, which are more energy-efficient than traditional incandescent bulbs.
The NLC also provides guidelines for the illumination levels required for different types of spaces. For example, it specifies that the illumination levels in commercial and industrial spaces should be higher than those in residential buildings. The code also provides guidelines for the placement and spacing of light fixtures, which helps to ensure that lighting is evenly distributed throughout the space.
In addition, the NLC includes guidelines for the maintenance of lighting systems. Regular maintenance is important to ensure that lighting systems are working effectively and efficiently. The code recommends that lighting systems be inspected and maintained on a regular basis to prevent failures and to ensure that they are operating at peak efficiency.
The NLC is an important document that helps to ensure that lighting systems in India are safe, effective and energy-efficient. Implementation of the code can help to reduce energy consumption, lower greenhouse gas emissions, and improve the safety and comfort of those who use the spaces where the lighting systems are installed.
Installation aspects of lighting in National Lighting Code
Lighting is an integral part of any building, whether it is residential or commercial. The National Lighting Code in India provides guidelines for the installation and use of lighting systems in buildings to ensure safety, energy efficiency, and maximum performance. Here we highlight the installation aspects of lighting in the National Lighting Code in India.
The National Lighting Code in India requires proper installation of lighting systems to ensure safety and correct functioning of the equipment. The code requires that all wiring and fixtures must be installed by a licensed electrician in accordance with the Electrical Safety Code. The installation must be done in such a way that it does not create a hazard to building occupants, nor does it cause any damage to the building structure.
The code also requires that wiring and fixtures must be installed in such a way that they are accessible for maintenance and repair. The wiring must be routed in a way that it does not interfere with other building systems or create a fire hazard. All wiring must be properly grounded, and light fixtures must be secured in place to prevent them from falling.
The National Lighting Code in India also sets guidelines for the placement of light fixtures to ensure optimal lighting performance. For example, it recommends that lighting fixtures be placed at a height that allows for even distribution of light and reduces glare. The code also recommends the use of energy-efficient lighting sources. It sets minimum requirements for the efficacy of various types of lamps and the maximum power usage of lighting fixtures.
Do exterior lighting in buildings, malls and stadiums follow the National Lighting Code? Priti Bhatnagar, Head – Electro Technical Division, Bureau of Indian Standards (BIS) answers this emphasising on the motto. “There is no regulation to follow the national lighting code. It is not mandatory to follow this code. All the people who are involved in the installation of lights and all. This is one part which we will be taking up now. Earlier due to lack of information and popularisation, NLC has not been taken up in a big way which should have been done earlier itself. But now when we are going for the revision, we will ensure that not only the document is revised and a comprehensive code is brought out but we will also take up with the government and private sectors to popularise and we will make people aware of the document so that now it can become a part of the regulation.”
What should be the wattage of streetlight ?
The required wattage of a streetlight in India will depend on various factors such as the street size, traffic density, and the level of illumination required. Generally, streetlights in India range from 40 watts to 250 watts. However, it is recommended that LED lights be used as they consume less energy and have a longer lifespan. The wattage for LED streetlights can range from 20 watts to 150 watts. Ultimately, the appropriate wattage of a streetlight in India should be determined by a qualified electrical engineer or lighting designer.
Mr. Utkarsh Singh, Assistant Manager (Technical) from Energy Efficiency Services Limited (EESL), helps us understand the guidelines and parameters, which are to be considered during installation of Streetlights on public streets and roads.
1.) On a single side arrangement, where all luminaires are on one side of the road, there the height of the Street lighting pole is directly related to the width of the area to be illuminated. Means, the width of the area to be illuminated by the lighting fixture is roughly equal to the height of the lighting pole.
2.) The spacing/pole span (i.e. distance between two successive poles); the space-height ratio should generally be between 2.5 to 3. This helps in preserving longitudinal uniformity of road surface luminance, which is the ratio of minimum luminance to maximum luminance. Also, shorter Streetlight poles should be installed at closer intervals to meet the above criteria and avoid formation of dark spots between two poles.
3.) Depending on the mounting height of the Streetlight/luminaire, it is advisable to keep the angle of tilt between 15 to 30 degrees. This range of angles allows for optimal illumination while reducing the chances of a discomfort glare on drivers.
Moreover, he explains that in the case of LEDs, they emit light at a 120-degree angle when no optical material is used. However, an optical material can be placed on LED package, which can shift the light beam angles to 30, 60 or 90 degrees. Thus, the beam angle also plays an important role in non-formation of dark spots on road between two successive poles, in case of LED Streetlight luminaires.
The above basic standards for road-pole configuration needs to be enforced along with suitable selection of Streetlight wattages as per the categorization of road types to have an efficient Street lighting system.
Box item 6
In 1878, the first electric street light poles were installed in Paris
Box item 7
First streetlight in India was installed in 1905 in Bangalore.
Box item 8
History of Streetlights in India
Bangalore city, once referred to as the ‘garden city of India’ for its lush greenery and pleasant weather, has transformed over the years to become India’s silicon valley. The city has also undergone tremendous changes in terms of its infrastructure, with the first streetlight being installed in 1905 in the Chickpet area, which at that time was a bustling market area. It was a kerosene lamp, which was manually lit every evening by the lamp lighter. This was the only source of illumination for the people commuting and working in the area.
However, with time, Bangalore started to grow, and the need for proper street lighting increased. As a result, in 1937, the Bangalore City Corporation decided to install electric streetlights. The new streetlights were installed in the central business districts and by 1940, more than 3,000 streetlights were installed across the city. In the 1970s and 1980s, as Bangalore became the hub of India’s IT industry, there was a significant increase in the population of the city. With a rise in population came the need for more advanced infrastructure. Therefore, the street lighting system was upgraded once again, this time with the introduction of high-pressure sodium lamps.
In 2011, the Bangalore City Corporation initiated a project to replace the older streetlights with energy-efficient LED lights. The new LED lights save electricity and have a longer lifespan than the previous lighting systems. Today, Bangalore’s streetlight infrastructure has come a long way from the kerosene lamps of 1905. The city is now dotted with modern and energy-efficient streetlights, which provide illumination to the city’s streets and footpaths. The streetlights are now controlled by a centralized computer system, making them more efficient in their usage of electricity.
Difference between conventional street lights and smart and energy efficient LED street lights
The traditional street lighting system that we have been using for so long has become outdated and inefficient. Fortunately, with advancements in technology, we now have a more efficient and cost-effective solution – smart and energy-efficient LED street lights. In 2015, India launched Street Lighting National Program (SLNP) to replace conventional street lights with smart and energy efficient LED street lights across the country. So, what makes LED street lights different from the conventional street lights that we have been using for decades? Our experts along with Neha Agl, Scientist ‘C’ at Bureau of Indian Standards have almost similar observations and suggestions. I am listing them here.
1. Energy Efficiency:
One of the most significant differences between conventional street lights and LED street lights is their energy efficiency. LED street lights consume less electricity than their traditional counterparts. As per the reports, LEDs can save around 50% to 70% of energy compared to the conventional street light systems. This not only reduces the carbon footprint but also helps to reduce the energy bills for local governments.
2. Longevity:
Conventional street lights have a short lifespan and require frequent maintenance, which can be a time-consuming and costly affair. LED street lights have a much longer lifespan, with some models rated to operate up to 100,000 hours while requiring minimal maintenance. This leads to a lower replacement frequency, reducing the overall cost of ownership.
3. Smart technology:
LED street lights integrated with smart technology sensors can detect the presence of vehicles, pedestrians and adjust their light output automatically. This helps to conserve energy by only illuminating the area when it’s needed. Smart LED street lights can work with various control systems such as software applications, wireless connectivity and can be monitored by a central control unit. They also have the capability to adjust the light output in real-time, and track and report failures remotely, eliminating the need for manual inspection.
4. Environmental sustainability:
Conventional street lights pose a threat to the environment, as they contain harmful chemicals such as mercury, which can cause pollution when not disposed of correctly. LED street lights, on the other hand, are environment-friendly and contain no toxic chemicals, and can be recycled easily.
Anil Kumar Choudhary, Head Operations (Lighting) at EESL LED lights come with the fixtures and are designed in such a way that all the light is going downwards only. There is a conical curve so light comes to the surface only. The old High pressure sodium lamps do not have the same drivers and all, so if LED has to be installed then the total fixture has to be changed. We as an energy efficiency company have to make sure that old ones are not being used, otherwise our purpose is getting lost.”
Box item 9
The most common reasons for inefficient street lighting systems in municipalities are:
• Selection of inefficient luminaires
• Poor design and installation
• Poor power quality
- Poor operation and maintenance practices
Smart Solutions
India has attempted a lot of innovations in developing street lighting system in India over the years. While having detailed discussion with experts at EESL, here are some smart solutions suggested to tackle this genuine issue.
1. Solar-powered streetlights with automatic dimming sensors
2. Streetlights with decorative designs inspired by local culture and heritage
3. Smart streetlights with remote monitoring and control systems
4. Streetlights with built-in cameras for improved public safety
5. Energy-efficient LED streetlights with customizable colour temperatures
6. Streetlights with motion sensors to conserve energy
7. Streetlights that double as charging stations for electric vehicles
8. Streetlights with integrated air quality monitors
9. Streetlights with modular designs for easy maintenance and repair
10. Streetlights with adjustable heights for different road types and traffic densities
11. Streetlights with programmable light patterns for festivals and events
12. Streetlights with built-in sound systems for public announcements and emergency alerts.
NLC also suggests energy consumption for street lighting can be reduced by incorporating good maintenance practices such as :
• Replacing defective lamps, accessories and wires
• Early rectification of cable faults
• Making sure that cables are joined properly
• Regular maintenance of service cabinet/fuse box to avoid loose connections
• Regular cleaning of the luminaire cover to keep it free of dust/dirt and increase light output
A substantial amount of energy savings can also be achieved by installing mechanical/electronic timers and/or daylight sensors for turning street lights on and off.
Experts also confirm that the industry is getting ready for this but it will take time to be hi-tech in lighting system. As India continues to develop, we can expect to see more innovative and eco-friendly street light designs in the future. Also, the development of its public infrastructure, including street lighting, will play a crucial role in creating a safe, livable, and sustainable environment.
NehaScope 
Note : This story was published in CSIR-NISCAIR’s prestigious magazine ‘ Science Reporter’ in October 2023.
Street Lights : Smart Solutions for Energy-Efficient Lighting in India
Streetlights rarely catch our attention until and unless they are flickering or not working. We have our sight all around but never goes up to the streetlights lighting our path ahead. Even if we see the streetlights, they appear like some dead structures hanging in the middle and sides of the road.
India is a country that is home to a diverse range of cultures, traditions and customs. It is a land of contrasts, where the modern and the traditional coexist in harmony. One of the visible signs of this contrast is the street light designs that one can see across the length and breadth of the country.
The street light designs in India vary from region to region. One can see the traditional lantern-style designs in rural areas, while in urban areas, the designs are modern and sleek. The street lights in rural areas of India are made of metal or bamboo and are designed to look like lanterns. Some cities have even gone the extra mile to make their street lights eco-friendly by using solar panels.
India is a country that is rapidly developing, and the government is taking steps to modernize the infrastructure. Street light designs are a crucial part of this infrastructure. They are not only essential for public safety but also for beautifying the surroundings. One of the most striking examples of street light designs in India is in the city of Jaipur. Known as the ‘Pink City,’ Jaipur is famous for its beautifully designed buildings, and the street lights are no exception. The street lights in Jaipur are designed to complement the architecture of the city’s buildings, with intricate and ornate designs.
Another city that stands out for its street light designs is Bangalore. The street lights in Bangalore are modern and sleek, and many of them use LED technology. The city has also installed solar-powered street lights in some areas, which not only saves electricity but also helps to reduce carbon emissions.
Types of Streetlights
Streetlights play a vital role in maintaining the safety and security of public spaces in India. In recent years, advancements in technology and urban planning have led to significant improvements in the design of streetlights. We must explore the various aspects of streetlight design in India, including the types of streetlights, their placement, and the factors that influence their design.
In India, there are several types of streetlights that are commonly used. These include:
1. High-Pressure Sodium (HPS) Lamps: These lamps emit a warm, yellowish light and are commonly used on arterial roads, highways and expressways.
2. Light Emitting Diode (LED) Lamps: LED lamps are energy-efficient and have a longer lifespan than High-Pressure Sodium lamps. They are used in residential areas, parks, and pedestrian walkways.
3. Metal Halide Lamps: These lamps emit a bright white light and are used in commercial areas and stadiums.
Placement of Streetlights
The placement of streetlights is crucial to ensure sufficient lighting for public safety. In India, streetlights are placed based on various factors such as:
1. Traffic volumes: Streetlights are installed at regular intervals on arterials and highways to ensure better visibility for drivers.
2. Pedestrian traffic: In areas with high pedestrian traffic, streetlights are installed at lower heights to provide better illumination on footpaths.
3. Environmental factors: In areas with high wind speeds, streetlights are installed closer to the ground to prevent damage.
Box item 1
A busy road will need bright and wide-ranging lights to ensure the highest visibility for cars on the road.
Box item 2
Residential areas or small streets may require warm light that is not too bright to avoid disturbing residents.
Box item 3
Lights in parks or gardens may have a softer and more elegant design that blends well with the surrounding area.
Design Factors
Several design factors influence the design of streetlights in India, including:
1. Power supply: The power supply for streetlights in India is typically 230V AC, 50Hz.
2. Light intensity: The intensity of light provided by streetlights varies depending on the location and purpose of the lighting.
3. Mounting height: The mounting height of streetlights varies based on the location and type of streetlight used.
Who designs the lights ?
Lights are typically designed by professional engineers or lighting designers who have expertise in electrical engineering and lighting technology. These professionals work with local government agencies and contractors to determine the appropriate lighting requirements for a given location, taking into account factors such as traffic flow, safety, and aesthetics. The design process may also involve consideration of energy efficiency and sustainability in order to reduce the environmental impact of the street lights. Additionally, manufacturers may also have in-house engineering teams who design and develop street lights for production.
Anil Kumar Choudhary, Head Operations (Lighting) at EESL explains that “For installation of new lights everything is decided by EESL. Overall standard design requirements for the lights is given by EESL along with the specifications and lux level on the ground is given by EESL. But the lights and fixtures are manufactured by the selected manufacturing companies. Our specifications are way ahead then what is prevailing in the market because we are bringing in all the time better product than what is available.
Box Item 4
The design of a street lighting system must be appropriate for the site and should provide the level of illumination (lux) and uniformity of light specified in the Indian Standard (BIS, 1981).
How streetlights are designed in India ?
Streetlight design in India has evolved significantly over the years, with a focus on safety and energy efficiency. By understanding the various types of streetlights, placement considerations, and design factors, we can ensure that our streets are well-lit and safe for all.
In India, streetlights have come a long way and have undergone a significant transformation in the past couple of decades. The country has been proactive in adopting advanced lighting technologies and has made considerable advancements in the design of streetlights. The design of streetlights in India takes into account a variety of factors, including the location of the street, the cost-effectiveness of the solution and the environmental impact. Streetlights are designed to enhance visibility at night, reduce accidents, and provide for a safe and well-lit environment.
One of the most significant advancements in streetlight design in India is the introduction of LED lighting technology. LEDs are highly energy-efficient and cost-effective when compared to conventional lighting. The use of LED lights in streetlights has resulted in a significant reduction in energy consumption and has helped in minimizing the carbon footprint. This has made LED lighting a popular option for public lighting systems throughout India.
Moreover, the Indian government has been working to make streetlights more environmentally friendly. Solar-powered streetlights are being installed in various regions across the country. These streetlights work using solar panels that collect energy during the day, store it in batteries and use it to power the LED lights at night. This technology reduces the dependency of streetlights on electricity and lowers the carbon footprint of the country.
Furthermore, the design of Indian streetlights is also focused on durability and low maintenance. The lights are housed in sturdy, weather-resistant enclosures that protect them from the elements and prevent damage due to vandalism or accidents. Additionally, the components used in the lights are of high quality and require little maintenance, reducing the need for frequent repairs and replacements.
Box Item 5
Lighting components can be grouped based on their functions. They are generally described as the structural systems, electrical systems, and optical systems. The items covered include :
Structural
• Poles
Optical
Electrical
• Lamps
• Ballasts
Factors considered for streetlights
Choosing the right type of streetlight involves several factors that need to be considered. Some of these factors include height, distance, bulb, angle, and design. An optimal balance of these factors is crucial for road safety and maintaining the overall illumination of the city. It is essential to choose streetlights that provide visibility while not causing light pollution, and that are aesthetically pleasing to the surroundings.
National Lighting Code (NLC)
The National Lighting Code (NLC) is a document that sets out the minimum standards for lighting design, installation and maintenance in India. The code was developed by the Bureau of Indian Standards (BIS) in collaboration with the Indian Society of Lighting Engineers (ISLE).
The NLC provides guidelines to ensure that lighting is provided in a manner that is safe, effective and energy-efficient. The code covers indoor and outdoor lighting systems, including street lighting, lighting in parks and public spaces, and lighting in commercial and residential buildings.
One of the key objectives of the code is to ensure that lighting is energy-efficient, which helps to reduce energy consumption and greenhouse gas emissions. The code recommends the use of energy-efficient lighting technologies such as LED (light-emitting diode) and CFL (compact fluorescent lamp) bulbs, which are more energy-efficient than traditional incandescent bulbs.
The NLC also provides guidelines for the illumination levels required for different types of spaces. For example, it specifies that the illumination levels in commercial and industrial spaces should be higher than those in residential buildings. The code also provides guidelines for the placement and spacing of light fixtures, which helps to ensure that lighting is evenly distributed throughout the space.
In addition, the NLC includes guidelines for the maintenance of lighting systems. Regular maintenance is important to ensure that lighting systems are working effectively and efficiently. The code recommends that lighting systems be inspected and maintained on a regular basis to prevent failures and to ensure that they are operating at peak efficiency.
The NLC is an important document that helps to ensure that lighting systems in India are safe, effective and energy-efficient. Implementation of the code can help to reduce energy consumption, lower greenhouse gas emissions, and improve the safety and comfort of those who use the spaces where the lighting systems are installed.
Installation aspects of lighting in National Lighting Code
Lighting is an integral part of any building, whether it is residential or commercial. The National Lighting Code in India provides guidelines for the installation and use of lighting systems in buildings to ensure safety, energy efficiency, and maximum performance. Here we highlight the installation aspects of lighting in the National Lighting Code in India.
The National Lighting Code in India requires proper installation of lighting systems to ensure safety and correct functioning of the equipment. The code requires that all wiring and fixtures must be installed by a licensed electrician in accordance with the Electrical Safety Code. The installation must be done in such a way that it does not create a hazard to building occupants, nor does it cause any damage to the building structure.
The code also requires that wiring and fixtures must be installed in such a way that they are accessible for maintenance and repair. The wiring must be routed in a way that it does not interfere with other building systems or create a fire hazard. All wiring must be properly grounded, and light fixtures must be secured in place to prevent them from falling.
The National Lighting Code in India also sets guidelines for the placement of light fixtures to ensure optimal lighting performance. For example, it recommends that lighting fixtures be placed at a height that allows for even distribution of light and reduces glare. The code also recommends the use of energy-efficient lighting sources. It sets minimum requirements for the efficacy of various types of lamps and the maximum power usage of lighting fixtures.
Do exterior lighting in buildings, malls and stadiums follow the National Lighting Code? Priti Bhatnagar, Head – Electro Technical Division, Bureau of Indian Standards (BIS) answers this emphasising on the motto. “There is no regulation to follow the national lighting code. It is not mandatory to follow this code. All the people who are involved in the installation of lights and all. This is one part which we will be taking up now. Earlier due to lack of information and popularisation, NLC has not been taken up in a big way which should have been done earlier itself. But now when we are going for the revision, we will ensure that not only the document is revised and a comprehensive code is brought out but we will also take up with the government and private sectors to popularise and we will make people aware of the document so that now it can become a part of the regulation.”
What should be the wattage of streetlight ?
The required wattage of a streetlight in India will depend on various factors such as the street size, traffic density, and the level of illumination required. Generally, streetlights in India range from 40 watts to 250 watts. However, it is recommended that LED lights be used as they consume less energy and have a longer lifespan. The wattage for LED streetlights can range from 20 watts to 150 watts. Ultimately, the appropriate wattage of a streetlight in India should be determined by a qualified electrical engineer or lighting designer.
Mr. Utkarsh Singh, Assistant Manager (Technical) from Energy Efficiency Services Limited (EESL), helps us understand the guidelines and parameters, which are to be considered during installation of Streetlights on public streets and roads.
1.) On a single side arrangement, where all luminaires are on one side of the road, there the height of the Street lighting pole is directly related to the width of the area to be illuminated. Means, the width of the area to be illuminated by the lighting fixture is roughly equal to the height of the lighting pole.
2.) The spacing/pole span (i.e. distance between two successive poles); the space-height ratio should generally be between 2.5 to 3. This helps in preserving longitudinal uniformity of road surface luminance, which is the ratio of minimum luminance to maximum luminance. Also, shorter Streetlight poles should be installed at closer intervals to meet the above criteria and avoid formation of dark spots between two poles.
3.) Depending on the mounting height of the Streetlight/luminaire, it is advisable to keep the angle of tilt between 15 to 30 degrees. This range of angles allows for optimal illumination while reducing the chances of a discomfort glare on drivers.
Moreover, he explains that in the case of LEDs, they emit light at a 120-degree angle when no optical material is used. However, an optical material can be placed on LED package, which can shift the light beam angles to 30, 60 or 90 degrees. Thus, the beam angle also plays an important role in non-formation of dark spots on road between two successive poles, in case of LED Streetlight luminaires.
The above basic standards for road-pole configuration needs to be enforced along with suitable selection of Streetlight wattages as per the categorization of road types to have an efficient Street lighting system.
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In 1878, the first electric street light poles were installed in Paris
Box item 7
First streetlight in India was installed in 1905 in Bangalore.
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History of Streetlights in India
Bangalore city, once referred to as the ‘garden city of India’ for its lush greenery and pleasant weather, has transformed over the years to become India’s silicon valley. The city has also undergone tremendous changes in terms of its infrastructure, with the first streetlight being installed in 1905 in the Chickpet area, which at that time was a bustling market area. It was a kerosene lamp, which was manually lit every evening by the lamp lighter. This was the only source of illumination for the people commuting and working in the area.
However, with time, Bangalore started to grow, and the need for proper street lighting increased. As a result, in 1937, the Bangalore City Corporation decided to install electric streetlights. The new streetlights were installed in the central business districts and by 1940, more than 3,000 streetlights were installed across the city. In the 1970s and 1980s, as Bangalore became the hub of India’s IT industry, there was a significant increase in the population of the city. With a rise in population came the need for more advanced infrastructure. Therefore, the street lighting system was upgraded once again, this time with the introduction of high-pressure sodium lamps.
In 2011, the Bangalore City Corporation initiated a project to replace the older streetlights with energy-efficient LED lights. The new LED lights save electricity and have a longer lifespan than the previous lighting systems. Today, Bangalore’s streetlight infrastructure has come a long way from the kerosene lamps of 1905. The city is now dotted with modern and energy-efficient streetlights, which provide illumination to the city’s streets and footpaths. The streetlights are now controlled by a centralized computer system, making them more efficient in their usage of electricity.
Difference between conventional street lights and smart and energy efficient LED street lights
The traditional street lighting system that we have been using for so long has become outdated and inefficient. Fortunately, with advancements in technology, we now have a more efficient and cost-effective solution – smart and energy-efficient LED street lights. In 2015, India launched Street Lighting National Program (SLNP) to replace conventional street lights with smart and energy efficient LED street lights across the country. So, what makes LED street lights different from the conventional street lights that we have been using for decades? Our experts along with Neha Agl, Scientist ‘C’ at Bureau of Indian Standards have almost similar observations and suggestions. I am listing them here.
1. Energy Efficiency:
One of the most significant differences between conventional street lights and LED street lights is their energy efficiency. LED street lights consume less electricity than their traditional counterparts. As per the reports, LEDs can save around 50% to 70% of energy compared to the conventional street light systems. This not only reduces the carbon footprint but also helps to reduce the energy bills for local governments.
2. Longevity:
Conventional street lights have a short lifespan and require frequent maintenance, which can be a time-consuming and costly affair. LED street lights have a much longer lifespan, with some models rated to operate up to 100,000 hours while requiring minimal maintenance. This leads to a lower replacement frequency, reducing the overall cost of ownership.
3. Smart technology:
LED street lights integrated with smart technology sensors can detect the presence of vehicles, pedestrians and adjust their light output automatically. This helps to conserve energy by only illuminating the area when it’s needed. Smart LED street lights can work with various control systems such as software applications, wireless connectivity and can be monitored by a central control unit. They also have the capability to adjust the light output in real-time, and track and report failures remotely, eliminating the need for manual inspection.
4. Environmental sustainability:
Conventional street lights pose a threat to the environment, as they contain harmful chemicals such as mercury, which can cause pollution when not disposed of correctly. LED street lights, on the other hand, are environment-friendly and contain no toxic chemicals, and can be recycled easily.
Anil Kumar Choudhary, Head Operations (Lighting) at EESL LED lights come with the fixtures and are designed in such a way that all the light is going downwards only. There is a conical curve so light comes to the surface only. The old High pressure sodium lamps do not have the same drivers and all, so if LED has to be installed then the total fixture has to be changed. We as an energy efficiency company have to make sure that old ones are not being used, otherwise our purpose is getting lost.”
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The most common reasons for inefficient street lighting systems in municipalities are:
• Selection of inefficient luminaires
• Poor design and installation
• Poor power quality
Smart Solutions
India has attempted a lot of innovations in developing street lighting system in India over the years. While having detailed discussion with experts at EESL, here are some smart solutions suggested to tackle this genuine issue.
1. Solar-powered streetlights with automatic dimming sensors
2. Streetlights with decorative designs inspired by local culture and heritage
3. Smart streetlights with remote monitoring and control systems
4. Streetlights with built-in cameras for improved public safety
5. Energy-efficient LED streetlights with customizable colour temperatures
6. Streetlights with motion sensors to conserve energy
7. Streetlights that double as charging stations for electric vehicles
8. Streetlights with integrated air quality monitors
9. Streetlights with modular designs for easy maintenance and repair
10. Streetlights with adjustable heights for different road types and traffic densities
11. Streetlights with programmable light patterns for festivals and events
12. Streetlights with built-in sound systems for public announcements and emergency alerts.
NLC also suggests energy consumption for street lighting can be reduced by incorporating good maintenance practices such as :
• Replacing defective lamps, accessories and wires
• Early rectification of cable faults
• Making sure that cables are joined properly
• Regular maintenance of service cabinet/fuse box to avoid loose connections
• Regular cleaning of the luminaire cover to keep it free of dust/dirt and increase light output
A substantial amount of energy savings can also be achieved by installing mechanical/electronic timers and/or daylight sensors for turning street lights on and off.
Experts also confirm that the industry is getting ready for this but it will take time to be hi-tech in lighting system. As India continues to develop, we can expect to see more innovative and eco-friendly street light designs in the future. Also, the development of its public infrastructure, including street lighting, will play a crucial role in creating a safe, livable, and sustainable environment.
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