The light efficiency of LED street lamps and high-pressure sodium lamps is similar, so why can LED street lamps use lower power instead of higher power high-pressure sodium lamps?

High-pressure sodium lamps are point light sources and emit 360 degrees of light. In fact, the light applied to the irradiation direction is very small, only about 30%. Therefore, the high-pressure sodium lamp must reflect the light in the non-irradiated direction through the reflector cover in the lamp to achieve the purpose of higher light utilization. Due to the design and cost of the lamps, the efficiency of sodium lamps is only 40-45%.

The LED street lamp/tunnel lamp belongs to the surface light source, the luminous surface is a single direction, the light source utilization is high, and the lamp efficiency reaches more than 80%.

Below we take 100W LED street lights and 250W high-pressure sodium lamps as an example to illustrate this problem.

1.100W LED street lamp initial luminous flux 11000lm. Because the lens loses 10% and the power supply loses 10%, the luminous flux of the lamp is actually 8910lm, and the total power consumption of the lamp is 110W. Therefore, the luminous efficiency of this LED street lamp is 81lm/W.

2.250W high-pressure sodium lamp initial luminous flux is 25000lm, the light source utilization loss is about 30%, the power loss is about 20%, the lamp luminous flux is actually 12500lm, the total power consumption of the lamp is about 300W. Therefore, the luminous efficiency of this high-pressure sodium lamp is 41.67lm/W.

Through the above analysis and comparison of the final light efficiency value, we can find that the light efficiency of 100W LED street lamps is almost twice that of 250W high-pressure sodium light efficiency. This is why 250W high-pressure sodium lamps can be replaced with 100W LED street lights.

After talking about the problem of light efficiency, talk about the certification standards for street lamps.

Local standard for street lamps

Us standard: Fixed lamp UL1598 and LED special UL8750
European Regulation: EN60598-1,EN60598-2-3
China: GB7000.5-2005
IEC: IEC60598-2-3:2003

As the United States is a key export market, it is necessary to make a special mention.

The safety requirements of LED lighting products in the US market are mainly UL, ETL, CSA, MET, cTUVus and other certifications. The main certification test standards are UL 8750, UL 1598, UL 153, UL 1993, UL 1574, UL 2108, UL 1310, UL 1012 and UL 60950-1.

Among them, UL 8750 is the safety requirements for the use of LED light sources in lighting products, including the requirements of the use environment, mechanical structure, electrical mechanism and so on. In terms of test evaluation, the main tests of UL 8750 are: test evaluation related to electric shock hazard, test evaluation related to thermal hazard, test evaluation related to mechanical and electrical structure, test evaluation related to energy hazard, material evaluation related to fire prevention, test evaluation related to application environment, etc.

UL 1598 is a safety requirement for stationary lamps, which do not have power cord plugs, including step lamps, ceiling lamps, chandeliers, wall lamps, street lamps, column lamps, etc.
UL 153 is a safety requirement for portable lamps with power cord plugs, including hand lamps, cabinet lamps, table lamps, floor lamps, etc.
UL 1993 is a safety requirement for self-ballast lamps and lamp adapters that contain driver circuits, such as LED bulbs, compact fluorescent lamps CFL, etc.
UL 1574 and UL 2108 are safety requirements for tunnel lighting systems and low voltage lighting systems, respectively.
UL 1310 is applicable to power supplies with a Class 2 safety loop, and UL 1012 is applicable to power supplies without a Class 2 safety loop.
UL 60950-1 specifies power supplies that can have LPS safety loops.

For LED lighting products to do UL certification, UL 8750 is a required test item, and according to the product category and the category of power supply, it is necessary to increase the corresponding lamp class and power class standard testing items. For the safety testing and certification of LED lighting products, the emphasis of the EU CE certification and the United States UL certification is different, CE certification focuses on the safety of the product against electric shock, while UL certification focuses more on the fire safety of the product.

The United States has the world's leading LED lighting technology, has many years of lighting energy-saving promotion and management experience. There are 52 million street lights in the United States, the largest urban lighting system in the world. 50% are road lights, 50% are street lights and city public square lights. The US Department of Energy began in 2009 to implement a plan to replace existing street lights with leds. Through several years of practice summary, the current LED road lighting has formed a consensus, and steadily embarked on the development direction of capital management with unified economic and use effects. Within ten years, only LED street lights in the world will have a market size of more than 50 billion US dollars, and it has begun to enter the growth period. Product design and application changes with each passing day, will inevitably break through the old model. Comparing the different experiences of China and the United States, learning from each other will help promote the promotion and application of LED street lights, guide the future construction of street lights, product development and future market development.