Metal Halide

Loose connections/bad lampholders/dodgy switches. can bugger up these lamps. Also you're not supposed to handle them with your bare fingers. (Results in carbon deposits which cause hot spots on the glass, hence micro cracks) . Some are not intended for indoor use, too warm for them. Check recommended max ambient temperatures. Plus they need ventilation some not suitable for closed fittings.

Dust on the glass can bugger them up. (Overheating)

Be better to get LED replacements, save electricity.

Dave I think I would counsel your brother to very careful about what he does ?maintenance? wise, changing a few light bulbs might not be a big issue but I would be very careful regards doing more. Charitable organisations are very good at getting volunteers to save them a bit of money and many kind hearted people are only too willing to help out. The problem comes should anything go wrong, presumably your brother will not have public liability insurance so he would have to make sure the church had insurance and more specifically if it covered him for ?volunteering?.

Remember the old adage ?where there is blame, there is a claim?

I couldn't see anything in the ballpark of 20,000 lumen LEDs ...

Andy Burns presented the following explanation :

They can be had, but rather specialised and expensive. Discharge lighting would be a better/ cheaper option.

I did see high-bay LEDs (as you say not cheap) but nothing that looked like replacement for E40 lamps

Andy Burns explained on 03/02/2020 :

No, you would have to replace the light fittings too.

and you might not be able to dim them with the curent dimming system.

At least if you fall off the ladders you will be closer to God.

That reminds me of a story related to me by a friend. He was head of the craft dept. of a RC secondary school, he was approached by the chair of governors who just happened to be the parish priest of the nearby RC church. The church though a modern building had quite a considerable bell tower and it had an arrangement where during the consecration an altar server could press a button and the main bell would bong at the high point of the mass. Unfortunately it had a tendency to jam but the fix was fairly simple you just had to clatter an appropriate part of the mechanism with a hammer and you were good for another while. Wanting to further his career my friend agreed to do the fix and set off up the tower. Initially there was some proper stairs up a couple of flights then it became a vertical climb up a ladder into what seemed infinity. When you reached the top there was a heavy guano encrusted hatch to shoulder off to eventually climb out on a narrow platform dominated by a bell that filled most of the available space and a parapet that only came up to his knees and no railings. On his return to terra firma the priest said ?Mr. H you won?t mind doing that again if needs be?? When my friend questioned the safety of what he had just done and explained to the priest who had never been up there what it was like. His reply was ?no need to worry you were doing Gods work, besides I would pray for you!? My friend was never sure if he meant for his safe return or for his funeral!

Richard

NT

Is it a case of overkill in much the same way as people used to fit 500W halogen lights on the side of their house when 150W halogen would have been more reasonable, but still with too much light?

We had a lamp fail in our belltower. (Venture MH-DE 70W/UVS/3K Clear Metal Halide) not having a spare to hand we replaced it with a normal halogen 250W linear bulb, works just as well, gives the same light. I now have the correct replacement which was expensive, delicate, and even the manufacturers data says it isn't colour consistent. So it will probably stay unused, as far as I can tell metal halide is a somewhat redundant technology, lower power consumption than halogen but if you really care about that then use LED.

Quite. But then those who reply LEDs to everything seem happy living in the gloom. ;-)

Dave Plowman (News) expressed precisely :

LED needn't be gloomy at all.

Indeed, some LED floodlights are 100 watts!

Care to guess at the cost of replacing 10 20,000 lumen fittings with LEDs of the same output?

TLC do sell 27,000 lumen LED fittings, but 10 of them would be enough to light warehouse, let alone a church hall. It sould be borne in mind that the metal halide lamps are probably no longer being manufactured due to EU requirements and an alternative light source will be needed in a few years.

Pfhht... Premier League footy ground, each pitch LED flood light is