Modern CFL Street lights really that efficient?

[eveares]

As I am sure most you have noticed, over the recent years many traditional street lights (Low pressure sodium and High Pressure Sodium) have been replaced with compact fluorescent lamps.

My question is, were the old streetlights replaced simply because of efficiency reasons or were their other reasons to such as colour temperature of the light and remote control-ability reasons?

Also are we really saving energy with these fluorescent street lights, when low
pressure sodium bulbs generally generates 100-140 lumens per watt, high pressure sodium bulbs generates 80-120 lumens per watt, and CFL's generates 50-70 lumens per watt.

(Yes, I know the old style magnetic ballasts on average take additional 20%-30% power up of the bulbs wattage; but does this really make CFL's with electronic ballasts cheaper to run, especially against low pressure sodium lights? )

(Surely it would be cheaper to replace existing magnetic ballasts with electronic ones rather than replace the whole lamp fixture?)

My guess is the governments/council initiative is to provide higher quality light, and be able to control them such as turning them off in early hours of the morning.

Whats your opinion?

 

[ban-all-sheds]

As I am sure most you have noticed, over the recent years many traditional street lights (Low pressure sodium and High Pressure Sodium) have been replaced with compact fluorescent lamps.

I hadn't.

MH, yes. LED, yes. Not CFL.

 

[RF Lighting]

Leeds City council seem to be using CFL on the majority of side roads and housing estates, but sticking with discharge fittings on main roads.

 

[ekmdgrf]

I seem to recall from reading that fountain of all internet knowledge* a while back (and I haven't been back to check) that CFLs found favour partly because the broader spectrum gave a more pleasent light but also that in doing so, it allowed to do reduce the power too*.

I believe that Internet legend* PhotonicInduction recently installed a low-pressure Na lamp outside his house to counter the council turning off his street lamps in the small hours.

As another incidental piece of trivia, many moons ago, I sat a GCSE science paper and came across a question** "you place a sample in a flame and the flame turns yellow, what is the sample?" Oops, it dawned on me that I'd completely forgotten to revise anything about flame tests. Then it occured to me that those Sodium street lamps produced a distinct yellow light. Day saved.

* [Citation Needed]
** One of many, actually

 

[ericmark]

I thought on walking Chester walls some one had smashed all the light bulbs then realised they were LED lamps.

Metal Halide lamps are normally 20W or more and the bulb is expensive as one hits the 70W mark the price seems to fall so where smaller outputs are required using LED or standard CFL does make some sense.

The 200 foot rule between lights, the 13 foot and 20 foot rule the latter combined with 50 foot rule mean the council has to space lamps and set at heights to make the 30 MPH speed limit enforceable.

I can find nothing about the size of bulb in a street lamp but I would think councils would be wary of using a size too small which could be sighted as a reason why some one should not pay a speeding fine.

Street lights have to light the road not just the pavement for the 30 MPH speed limit and I would not think a 20W lamp at 20 foot or more high and 50 foot apart would really light the road?

Remember nothing to do with common sense it's down to complying with the road traffic act.

 

[ekmdgrf]

I saw an old low-pressure Na street lamp on the Interweb*, which was 36W.

* So it must be true

 

[JohnD]

round my way they have replaced all the streetlamp heads.

The new ones have a "cold daylight" temperature which makes it much easier to see than the old orange, including colours, and are of an improved design which projects much more of the light onto the road surface, with very little spill into people's windows or up to the sky. I can imagine that when more of the light you pay for is actually useful, you can afford to run a lower-power lamp because there is not so much waste.

 

[ban-all-sheds]

There's always Plan B for showing what the speed limit is on a road.

 

[ericmark]

There's always Plan B for showing what the speed limit is on a road.

That would mean very careful measurement as if the street lights are not provided then to have a 30 MPH restriction means having repeaters but if it is lit then those repeaters are illegal.

Clearly the light from a bedroom window is not a street lamp, but anyone who gets caught speeding wants to get away with it, and to have to define when a street lamp is not a street lamp would be a legal nightmare.

No council wants to be in the news because some clever chap has found his speeding ticket is invalid specially if that means a 100 or so caught before that case are now also invalid so points need removing off licence and money refunding.

 

[robbieduncan]

This is the page for the program where I live: http://www.lewisham.gov.uk/myservices/transport/roads-and-pavements/Pages/street-light-renewal.aspx

Benefits mentioned are colour, remote controls and automatic notification of faults. Reduced power consumption is not noted (but may be a pleasant side effect)

 

[ekmdgrf]

Benefits mentioned are colour, remote controls and automatic notification of faults. Reduced power consumption is not noted (but may be a pleasant side effect)

Why can't one have remote control and fault monitoring on a low pressure Sodium lamp? Presumably the old lamps don't support that but then the solution is to swap the old system for one that does. That doesn't necessarily require changing the actual physics of the lamp.

 

[ban-all-sheds]

That would mean very careful measurement as if the street lights are not provided then to have a 30 MPH restriction means having repeaters but if it is lit then those repeaters are illegal.

Doesn't necessarily have to be that careful - the street lighting requirement is that they be not more than 183m apart. So only if they were right on the limit would you have to make very sure. If they were, say, 100m apart then someone could just pace it out and know that they weren't more than 183m.

And anyway - I did say that repeater signs were an alternative to having lighting.

 

[ekmdgrf]

That would mean very careful measurement as if the street lights are not provided then to have a 30 MPH restriction means having repeaters but if it is lit then those repeaters are illegal.

Doesn't necessarily have to be that careful - the street lighting requirement is that they be not more than 183m apart. So only if they were right on the limit would you have to make very sure. If they were, say, 100m apart then someone could just pace it out and know that they weren't more than 183m.

And anyway - I did say that repeater signs were an alternative to having lighting.

Sounds like you should get a job working for the council.

 

[jeff the gasman]

They've switched all our street lights off to save money. Brilliant.
They then put signs on to say street lights not in use!
Complete WINKERS

 

[flameport]

All of the streetlights in Dorset (other than Bournemouth and Poole) are being replaced, high pressure orange sodium for main roads, and some other white variety for all others.
Not entirely sure what the white ones are - but they are certainly not CFLs. Metal halide possibly.

This isn't just new heads either - the whole post is being replaced, and often the new are in different positions to the old ones. They are full cutoff types as well, so no light goes upwards.