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 Post subject: Re: The future of SON
PostPosted: Fri Jun 13, 2014 9:36 pm 
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sotonsteve wrote:
sevenman96 wrote:
I would say 90% at least of street lighting in Cornwall is Cosmopolis, Except for the odd SOX or SON that has been "overlooked" The PFI which started in 2009 is the reason why I believe.

So in my area SON is virtually extinct.


Cornwall does not have a street lighting PFI, they spent money on lantern replacements and upgrades themselves through an "invest to save" approach.

I didn't realise - Thanks for informing me. 8-)


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PostPosted: Thu Jul 10, 2014 5:17 pm 
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Something I've just learned about today is "white SON". I don't see it talked about very often and on researching it appears to be a predominantly American thing probably as they've always preferred white light.

They work like a normal SON lamp but run under even higher pressure. The spectral lines of sodium become wider as it is run under higher pressure, so combined with the mercury this results in it emitting a whiter light.

Has anyone heard of it before? I previously thought the closest thing to this would have been Cosmopolis but it's existed since the 80s so I'm surprised to see so little uptake in the UK.


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PostPosted: Thu Jul 10, 2014 5:54 pm 
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I am aware of white SON, but I don't think much of it. Thanks to advances in ceramic metal halide lamps it is a bit pointless, as ceramic metal halide lamps are more efficient and most likely now cheaper and longer life. I have seen some enthusiasts mention online about white SON street lighting, but I don't believe it was ever used in street lighting and that this was just confusion for ceramic metal halide.

In between standard SON and white SON are products such as the Philips SON Comfort lamps. These run with a creamier, whiter but nevertheless sodium tinted light, sort of halfway between metal halide and SON. These have seen use for street lighting, but they are absolutely rubbish. They are nowhere near as energy efficient as standard SON. For example, 150W SON-T Comfort produces 13000 lumens (85Lm/W) compared with 15000 lumens (98Lm/W) for standard 150W SON-T, or 17700 lumens (116Lm/W) for 150W SON-T PIA Plus. It's another case of this lamp being pointless. If you want white light you can use ceramic metal halide, otherwise use standard SON. What's the point in a lamp that is half and half yet costs more to run and is most likely more expensive to buy?


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PostPosted: Thu Jul 10, 2014 8:16 pm 
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I do miss SON and other yellow light types as the government seems to prefer white light sadly.


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PostPosted: Thu Jul 10, 2014 10:48 pm 
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sotonsteve wrote:
I am aware of white SON, but I don't think much of it. Thanks to advances in ceramic metal halide lamps it is a bit pointless, as ceramic metal halide lamps are more efficient and most likely now cheaper and longer life. I have seen some enthusiasts mention online about white SON street lighting, but I don't believe it was ever used in street lighting and that this was just confusion for ceramic metal halide.


I think it has seen use in the states as most of the information in a Google search brings America related products that I've seen so far. The states seem to value colour rendering and white light where possible, which is why I think they never gave LPS much time of day and in some places hung onto Mercury for a while. I know there are still some side streets in the US that are Mercury lit much like some of our side streets are still SOX lit, by virtue of simply having not needed to replace them yet.



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It's another case of this lamp being pointless. If you want white light you can use ceramic metal halide, otherwise use standard SON. What's the point in a lamp that is half and half yet costs more to run and is most likely more expensive to buy?


I'm sure it is pointless now (don't worry I've seen the figures for myself) but back when it was invented it was probably a lot more tenable, if not from a practical point of view to at least open people's eyes and drive the white light movement forward a bit. In the 80s we were also reeling from the economic decline that saw us roll out SOX lamps all over the place, so some fangled white light technology was probably the last thing on our minds which is why I guess it saw no uptake.




sevenman96 wrote:
I do miss SON and other yellow light types as the government seems to prefer white light sadly.


I won't really be missing HPS when it does go, but I do miss SOX, mainly for larger roads. I can take it or leave it on small streets, but I do think it's well suited to wider roads and motorways.

Although I'm a fan of SOX I'm not nostalgia blinded - I can see that white light is the future, but it annoys me that a lot of white light roll outs at the moment are ice white verging-on-blue-tinted LED crap. The only white light I've seen that I properly liked, in Manchester and Great Western Road (Glasgow) is a peachy-white light that I am 99% sure were CosmoPolis - ceramic metal halide. I'll also entertain warm white LEDs - whenever I do actually see one.

I do wonder with all these new developments in street lighting whether adventurous designs will start to come back. Our street lighting design has hardly been exciting since the beginning of the SOX era when I imagine generic SOX lanterns replaced quite a lot of nice mercury stock. It was of course the era of modernist design where due to the downturn, "function" was really the only goal of the design of, well everything, and that in itself became a design cue. Love it as I may there are a lot of SOX lanterns which you could hardly call an exciting design.


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PostPosted: Fri Jul 11, 2014 8:41 am 
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I am not aware that white SON has ever been used for street lighting purposes in the USA. The biggest thing to remember about the USA is that their energy costs are a fraction of what they are in Europe, and this has been the case for generations. Energy efficiency hasn't traditionally registered on their radars, and you only have to look at their cars to get another example of this. Only very recently have they started to think about their energy consumption thanks to volatile oil prices and increased environmentalism. That's why the most popular light sources in the past 50 years in the USA have been incandescent, mercury and high pressure sodium. Coincidentally, these light sources are cheap to buy.

Colour rendering isn't that important in the USA either. More often than not their mercury uses clear, non-colour corrected lamps which have very poor colour rendering. When it comes to high pressure sodium, we are aware of the colour rendering properties of this light source. As for metal halide, this light source is still not used all that much for street lighting, even though it is commonly found lighting commercial property. However, ceramic metal halide with a warm white output hasn't really taken off in America, and they are still charging on with using quartz metal halide lamps with a cool colour temperature.

I'm sure white SON is available in the USA, but like Europe I suspect it is more confined to indoor applications such as in-shop lighting. As I say, the American's aren't as energy conscious about the Europeans, and their lamp technology is nowhere near as cutting edge. They wouldn't go for something as frivolous as white SON for street lighting. And before you mention the spread of induction and LED street lighting in the USA, these light sources require minimal routine maintenance, which is one of the key reasons for their increasing popularity. Of course, government will say it's about saving the planet, but behind closed doors maintenance cost is the driver.


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PostPosted: Sat Oct 04, 2014 1:22 pm 
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I suspect that SON could outlive CosmoPolis...

This is quite a broad statement, so let me clarify and explain. The reason why SON gained popularity over mercury was because it could produce more light with less power. The downside was that the lamps and gear were more expensive. SON also gained popularity over SOX, as lamps (and I think gear) are cheaper and they offer improved colour rendering, at the expense of efficiency. After decades of technological developments, metal halide in the form of CosmoPolis offers a white light and vastly improved colour rendering over SON, and efficiency and lamp lifetimes that match or exceed SON lamps. This comes at the expense of the cost of lamps and gear. Now we have LED, which also offers white light but is crucially more efficient and is longer life, at the expense of the cost of the LED fittings.

The downfall of mercury lamps is their efficiency, and the downfall of SOX lamps is their monochromatic light and relatively high cost. Both these light sources have had their day and essentially only remain in production because sufficient numbers of lanterns in the world still use them. In the majority of places they are no longer even considered as options anymore. But look at CosmoPolis. Councils flocked to use it because it offered colour rendering improvements over SON without efficiency and lifetime disadvantages. Councils were willing to pay more to save more in the long term and get a better product. LED technology has comfortably stolen this crown. Yes, LED is still expensive but getting cheaper, but CosmoPolis is also expensive and not getting much cheaper. We are reaching a point where it is a no-brainer between CosmoPolis and LED.

So where does this leave SON? Worldwide, SON is still dominant, and CosmoPolis is most popular in Britain. Other countries in Europe haven't invested in CosmoPolis to the same extent as us. The comparisons still sit. SON may not produce the nicest light or be the most efficient, but it's efficient enough, and the bottom line is that it is a cheap option. CosmoPolis is not a cheap option and doesn't compare favourably against LED.


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PostPosted: Sat Oct 04, 2014 6:23 pm 
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Re: White SON lamps. I recall these lamps  (Philips SDW-T) were first introduced around 1987-88 and were aimed at retail and commercial interiors. I don't think they were ever marketed for use in streetlighting, as standard SON was already providing a "fashionable" alternative to SOX and MBF. Anyway, by tweaking the established SON parameters, a whiter light was produced which closely matched tungsten lamps, but with a better efficacy of 40 lumens/Watt. By marketing it as a viable alternative to LV dichroic halogens and the long established 150W PAR38 reflector lamps, a new application for SON was created. At about the same time, Thorn's newly introduced "Arcstream" lamp which used theatre spec CSI (compact source iodine) arc tube technology also came onto the market. This was again aimed at interior lighting but with a choice of CRI at 3000K or 4000K. Interestingly, I discovered many years ago that I could recreate the "White SON" effect by over-running a 50W SON-T on a 70W ballast! Perhaps that's why White SONs weren't as long lived as their more orthodox brethren.


Attachments:
File comment: The three types of discharge lamp discussed above. The Philips SDW-T "WhiteSON", the Arcstream lamp introduced by Thorn in the late 80s and the innovative 400W CSI lamp designed for use in stage lighting.
discharge1.JPG
discharge1.JPG [ 2.22 MiB | Viewed 11367 times ]
File comment: A close up of the 400W CSI lamp. This is an unused example.
discharge2.JPG
discharge2.JPG [ 2.12 MiB | Viewed 11367 times ]
File comment: A close up of the Arcstream lamp.
discharge3.JPG
discharge3.JPG [ 2.14 MiB | Viewed 11367 times ]
File comment: A scan of the "WhiteSON lamp from the 1987 Philips catalogue.
PhilipswhiteSON.JPG
PhilipswhiteSON.JPG [ 318.94 KiB | Viewed 11421 times ]

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Last edited by GreatNorburyStDepot on Sat Nov 01, 2014 11:04 pm, edited 2 times in total.
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PostPosted: Wed Oct 08, 2014 1:37 am 
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I actually have a WhiteSON light fitting in one of my boxes... an iGuizinni spotlight with tilt, the sort of thing you see in Morrisons lighting up the fruit and veg section. 100w lamp, but a push-fit and not screwcap.

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