All lanterns have a differing lifespan. Modern lanterns seem to have a lesser lifespan that traditional lanterns such as those running on leak or old magnetic gear. Some of the older lanterns in my area are approaching near 40 years in service particularly in parts of Northumberland and Gateshead where SON was not so widely brought in during 1990s and 2000s. Blaydon, just outside of Newcastle which consists of a dual carriageway running through its centre lit with mainly 135W SOX GEC Bricks. These have been doing over 30 years of service with just a few replacements most were because columns were so heavily corroded they had to be removed. In these cases Iridiums were used on the new columns. However a few years ago a large stretch of lighting on a very exposed area here originally supporting 20year old GRP version Alpha8s was replaced with ZX3s. Literally months after they were put up a SGS203 was fitted, then a short time after that a flat glass ZX3 was fitted.

On one hand we have lanterns over 30 years old which probably cost substantially less to buy although maybe not the most efficient to run on leak gear, and on the other hand we have expensive modern lanterns with electronic gear, seal safe optics which last less than two years.

It's the old addage that the more complicated you make something, the more there is to go wrong! Some people we know got a fancy new combi boiler a couple of years back and it just keeps going wrong... it'll boil over in the night, it goes bang every now and then, it trips the house RCD, and for a few months the only way it'd work was to have the cintrolling circuit board resting on a wooden spoon outside of the boiler itself! Then you get condensing boilers where the condensation pipe will freeze in winter and shut off the heating.... And on the other hand there is our 1980's boiler which has just a thermostat, flame fail device, high/low thermostat switch with neon indicators, then the gas bits itself and that's it... yet it passes the annual safety checks and just keeps going year in year out without issue even after full system drains for new radiators (and a leak we had in the first year at this house). We get bits in the post about "save XXX when we fit you a new boiler", but the cost of the new boiler plus costs to replace the fan/PCB/heat exchanger/ anything else fancy on it simply doesn't merit the change even if our existing boiler isn't as efficient as they can be....

And the same can go for lighting. Leak Transformers are old workhorses that will go for decades without issue even if not the most efficient method of power transfer. An electronic SON ballast? you'd be lucky to get 5 years out of it. The fact entire lanterns get replaced when the electronic ballast fails would suggest it is cheaper to get a whole new lantern rather than a new electronic ballast, or that on-site repairs cannot be done (probably the gear tray is not easy to remove) so a ballast swap has to be done at the depot.

_________________

Everything is made cheaply as possible for as much as possible. Likewise with electronic ballasts, which to me have as much use as a chocolate fireguard. Thinking about it though what could be the eventual and more disposable way of manufacturing a lantern - by fitting a non replaceable gear tray so if one thing is broken on it, the whole thing would have to be chucked. It'll happen eventually.

_________________
From streetlighting to radio, dance through the night whilst the streetlights are glowing outside.

I wouldn't be surprised if a non-replaceable gear tray was the next thing. Last year I rescued some old LPS Revo ballasts designed for use with old sodium lamps but I now just run a 90W SOX bulb on them. They were around 40 years old I guess and weighed a ton. You could fit five new SON ballasts into one of them. They had sat in a damp concrete column base with no power for over 10 years and they powered up first time.

Al I think ignitors are the cause of premature lantern failure. Poor quality ignitors in lanterns such as Sapphires, Iridiums, SGS203s and ZX2/3s. Have all meant that lanterns have been replaced after only a few years of service. Recently a MA90 was replaced because of a failed lamp and Durham seem to be not re-lamping SOX.

In the likes of WRTL Stela and Phillips SpeedStar can the LEDS be replaced or will they be scrapped once the lamp life is up? If so then LED lanterns are a con for efficiency and councils should look more towards Cosmo or CFL.

I think you need further evidence before you can say ignitors are at fault. For Sapphires and Iridiums electronic ballasts are increasingly used. At my local depot, evidence in the scrap bin does not support your statement. The most unreliable component tends to be the power correction capacitor, but this does not stop the lamp operating with the exception of those lanterns that use series capacitor gear, such as 135/180W SOX on leak gear.

Like everything in life now, lanterns have a finite lifetime. The manufacturers would soon go out of business if they made lanterns with a 40 year life time. The same for everything else - how often do you replace your mobile phone, TV, laptop, car etc etc...

I was just going by what one of the crews told me, they seemed to say electronic ballasts were the first biggest cause of short lantern life spans, then ignitors as these fail too. To back up your statement there was also a few capacitors in the skip at NWLs depot.

When I've seen scrap bins, there's been a fair old amount of electronic ballasts in there.... mainly the Harvard ones from QSMs.
LEDs - in some lanterns the LEDs come on array panels which can be replaced (like the Vexica ones just fitted in York) whilst others cannot (like the Stela)

_________________