LONDON -- Wigan Council has abruptly switched to warmer-colour LED luminaires for its streetlighting overhaul according to a campaigner concerned about possible harmful health effects from the colder, blue-tinged lamps the borough had originally specified.
The change appears to have come in response from public pressure. Lighting activist Simon Nicholas, who has warned Wigan and other municipalities about potential detrimental effects of LED streetlights, told an audience at LuxLive here last week that Wigan had informed him of the change when it wrote to him following his Freedom of Information (FOI) request.
'Yesterday I had an email from Wigan Council in response to my FOI and they themselves have agreed that the LED rollout will not now be 5,700 Kelvin, but will be 4,000 Kelvin,' Nicholas said during a panel discussion entitled Are LED streetlights bad for us?.
In the counterintuitive world of colour temperatures, a lower Kelvin (K) number is considered warmer than a higher number. Candle flames emit a warm light at under 2,000 K. Conventional incandescent bulbs – a benchmark of warm, but energy inefficient, artificial lighting – perform at around 3,000 K.
LED lamps and luminaires were known in their early days for emitting colder light, dominated by the blue spectrum at around 5,000 K or higher. While LEDs are much more energy efficient than conventional streetlighting, critics like Nicholas have challenged their use for various reasons including harmful health effects. Blue-tinged light can disrupt sleep and circadian rhythms, and has been linked to cancer, Nicholas and others have pointed out.
Since LEDs first hit the market, some manufacturers have started to make warmer models available, although they are not always as energy efficient as the colder lamps, which are still in ample supply.
And as Nicholas noted, municipal LED streetlighting initiatives – especially those backed by private financing schemes known as PFIs – can remain inflexibly locked into agreements with suppliers for colder temperature LEDs.
But that did not turn out to be the case at Wigan, according to Nicholas.
'I tackled them on the CCT (correlated colour temperature) a few weeks ago, and they've changed their policy,' he said.
Wigan had been planning to spend £11 million on 31,000 new Philips LED streetlights over the next three years, in an energy saving move. As of last August, it had already installed 5,500 of the new lamps.
Lux has asked Wigan to confirm its decision to use warmer LEDs, and to elaborate on why they made the change and how the new specifications might change the economics. A Wigan spokesman said he would look into it.
We will provide updates as we receive them.
Critics have also complained that LED luminaires provide patchy light that leaves some areas in the dark, and that they are subject to glare.
Photo is from Alice Hier