Does the street led lights CCT can over 3000K?

You may noticed that In few years ago ,we always get “Complaints over 'too bright' street lights.

The new LED street lights problem

Residents on a street in west London are complaining that the new LED street lights that have been installed in their street are that bright that it is beginning to affect their lives. The LED lights themselves stand 8 meters tall and were installed nearly three weeks ago.

Since they have been installed residents have been trying to do anything possible to combat the bright light such as blacking out their windows with blackout blinds and black cardboard to try and reduce the bright glare.

A resident of the street said “It’s like a great big spotlight beaming into your face when you’re trying to relax with your family and watch TV in the evening.”

 

Another resident said that he feels like he is in World War Two as they are living in darkness to reduce the brightness of the lights and they have no idea what’s going to happen In the upcoming weeks.

Hounslow Council plans to install LED street lighting throughout the borough and has looked at the idea of dimming the streetlights to deal with the problem.

It is not thought the problem is down to the use of LED lighting in general however when you begin to weigh up the pros and cons of LED street lighting it is been seen that there was not enough spill light from some of the LED luminaires.

Eddie Henry, operations manager at Southwark Council in London said, “We need a bit of spilled light so people can see as they leave the public highway and step across their gate, and it doesn’t go from being very light to completely dark very quickly.” 

The LED is very much predetermined by design; it allows you to put the light exactly where you want it,” he said. “So, in an average street, it will punch the light down to the road but the houses behind would be left in comparative darkness.

To watch the BBC London report about the Hounslow street lights, click here.

Doctors issue warning about too-bright LED streetlights

In LA ,we also find a news about “Doctors issue warning about too-bright LED streetlights”

The American Medical Association has just adopted an official policy statement about street lighting: cool it and dim it. The statement comes in response to the rise of new LED street lighting sweeping the country. An AMA committee issued guidelines on how communities can choose LED streetlights to "minimize potential harmful human health and environmental effects."

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Doctors issue warning about too-bright LED streetlights

The American Medical Association has just adopted an official policy statement about street lighting: cool it and dim it.

The statement comes in response to the rise of new LED street lighting sweeping the country.An AMA committee issued guidelines on how communities can choose LED streetlights to "minimize potential harmful human health and environmental effects."

Municipalities are replacing existing streetlights with efficient and long-lasting LEDs to save money on energy and maintenance. Although the streetlights are delivering these benefits, the AMA's stance reflects how important proper design of new technologies is and the close connection between light and human health.

The AMA's statement recommends that outdoor lighting at night, particularly street lighting, should have a color temperature of no greater than 3000 Kelvin. Color temperature is a measure of the spectral content of light from a source; how much blue, green, yellow and red there is in it. A higher CT rating generally means greater blue content, and the whiter the light appears.

A white LED at CT 4000K or 5000K contains a high level of short-wavelength blue light; this has been the choice for a number of cities that have recently retrofitted their street lighting, such as Seattle and New York. But in the wake of these installations have been complaints about the harshness of these lights. An extreme example is the city of Davis, California, where the residents demanded a complete replacement of these high color temperature LED street lights.

 

• Two problems with LED street lighting

Before electric light, we burned wood and candles at night; this artificial light has a CT of about 1800K, quite yellow/red and almost no blue. What we have now is very different.

An incandescent bulb has a color temperature of 2400K, which means it contains far less blue and far more yellow and red wavelengths than the new LED lights.

The new "white" LED street lighting has two problems, according to the AMA.

The first is discomfort and glare; because LED light is so concentrated and has high blue content, it can cause severe glare, resulting in pupillary constriction in the eyes. Blue light scatters more in the human eye than the longer wavelengths of yellow and red, and sufficient levels can damage the retina. This can cause problems seeing clearly for safe driving or walking at night.

You can sense this easily if you look directly into one of the control lights on your new washing machine or other appliance: it is very difficult to do because it hurts. Street lighting can have this same effect, especially if its blue content is high and there is not appropriate shielding.

The other issue addressed by the AMA statement is the impact on human circadian rhythmicity.

Color temperature reliably predicts spectral content of light -- that is, how much of each wavelength is present. It's designed specifically for light that comes off the tungsten filament of an incandescent bulb.

However, the CT rating does not reliably measure color from fluorescent and LED lights.

Another system for measuring light color for these sources is called correlated color temperature (CCT). It adjusts the spectral content of the light source to the color sensitivity of human vision. Using this rating, two different 3000K light sources could have fairly large differences in blue light content.

Therefore, the AMA's recommendation for CCT below 3000K is not quite enough to be sure that blue light is minimized. The actual spectral irradiance of the LED -- the relative amounts of each of the colors produced -- should be considered, as well.

• The reason lighting matters

The AMA policy statement is particularly timely because the new World Atlas of Artificial Night Sky Brightness just appeared last week, and street lighting is an important component of light pollution. According to the AMA statement, one of the considerations of lighting the night is its impact on human health.

In the case of white LED light, it is estimated to be five times more effective at suppressing melatonin at night than the high pressure sodium lamps (given the same light output), which have been the mainstay of street lighting for decades. Melatonin suppression is a marker of circadian disruption, which includes disrupted sleep.

 

KCOB LED STREET LIGHTS

If use K-COB LED Street light, Here are the merits that you could gain with our K-COB led, which is superior for street lighting, high mast lighting and sports lighting.

•1. Maximum wattage for traditional COB is 300W and it's extremely unstable, while KCOB could be more than 1500w with good reliability;

•2. Based on our dual heat-sink channel , allow K-COB size 15% smaller than normal COB. Easy for the light distribution design.

•3. CCT: 2000K-6500K, perfect for every industrial area. We absolutely can provide low CCT for street lights.

•4. Totally different standards for reliability. KCOB is the first-ever light source supplier who applies BACL LM80 test for 600w light source.

.5, we also can add Dimmer Switches on the street to control the amount of power being supplied to a LED light which in turn controls the brightness. The dimmer can be controlled in a number of ways such as manually or by a remote to adjust the level of lighting.

In today, the led street lights don’t strict CCT of lamps, just based on customer’s request. But we also can give some general suggestion as below: APPLICATIONS OF COLOR TEMPERATURE

 

Though which color temperature to use for a LED lighting project can be a matter of preference, different color temperatures are also useful for different applications.

STILL NOT SURE WHICH COLOR TEMPERATURE IS RIGHT FOR YOUR PROJECT?

Our Lighting expert is here to help. Contact us at dainel.lin@zkxyled.com and tell us about your project. We would be happy to make a recommendation and provide you with a no-obligation, volume-based quote.