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Thread: Requirement to have diffusers on light fittings? ( instead of wire mesh guard)

  1. #46
    Yes, I've got the T-shirt Sparkgap's Avatar
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    Getting back to the OP, I have only heard of a couple of incidences of fluoro fittings overheating in 30+ years. In most cases the giveaway was a smell of hot plastic and the light was turned off and replaced. The insides of these fittings have very little to burn, usually a ballast transformer and capacitor and the usual result is the fault takes out the local fuse before anything more serious can happen. High frequency fittings are more of a concern as they have a circuit board inside and in the past few years I have replaced several where some of the components have gone nice and crispy, though again this usually stops the light from working before it gets to the stage of calling the fire brigade.
    The lights in our main hall are ordinary 6ft twins with plastic diffusers and are still in one piece, though they are 6m in the air and we have always banned the use of hard balls.

    LED fittings are great but you have to remember the equivalent LED tube does not have as high a light output as a fluoro tube which can be an issue if you have a need for high lighting levels. I'm currently working out a cost proposal for replacing all the lights in our HQ with LEDs which we will put in for grant aid, especially as some of the lights were second hand when we put them in 20 years ago! As for savings, our main hall has 2000W of lighting which I reckon will drop to 800W with LED lights. A rough hourly cost for running the old lights is 32p and 12p for the new ones. With the hall in use for roughly 25 hours a week we will save about £5 a week just for the hall. Depending on cost of LEDs could pay back in only a couple of years.
    Andy
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    www.wellingtonscouts.org

  2. #47
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    I'm totally with you and be very interested in your maths and what lights you have currently in your hall that cost you 32p per hour (standard fluorescents being 58w you must have the equivalent of 34 5 foot bulbs which seems a lot for a hall or some other kind of lighting)

    Bearing in mind your comment on brightness id be interested in which LEDs youre looking at. Please also factor in the fact that while LEDs in theory last indefinitely, in reality they are an electrical item and will in fact periodically fail for no reason and cost money to replace!

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    We converted to LED fittings a couple of years ago. Light units "guaranteed" for 3 years. After a short while - 6 months or so they started to fail. Flickering quite badly, simply failing also. Guarantee, what guarantee - return the fittings to the supplier for testing prior to any sort of replacement!!! How prac tical is that? We persevered and changed some of the fittings ourselves successfully at first. These units are now failing. How I wish we had stayed with fluorescent lights. They didn't seem to fail although their brightness reduced significantly over time. After a few years - 5 or more - we used to retube the whole building - about 28 tubes at a time. We are now looking at a fuirther replacement using LEDs supplied and fitted by a local contractor who is well known and reliable. It will cost around 3000 to do this as we are vhaving the whole system reconfigured at the same time to give us more control over lighting specific parts of the hall. Not everything is progress and we still have the problem of recycling. It was easy with tubes; we simply took them to the local waste collection centre and put them in the special bin for fluorescent tubes.

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  5. #49
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    Quote Originally Posted by Dr_Pepper View Post
    I'm totally with you and be very interested in your maths and what lights you have currently in your hall that cost you 32p per hour (standard fluorescents being 58w you must have the equivalent of 34 5 foot bulbs which seems a lot for a hall or some other kind of lighting)

    Bearing in mind your comment on brightness id be interested in which LEDs youre looking at. Please also factor in the fact that while LEDs in theory last indefinitely, in reality they are an electrical item and will in fact periodically fail for no reason and cost money to replace!
    The main hall has 14 6ft (70W) twin fittings so about 2kW. Not sure of our electric prices but assuming 16p/kWh gives 32p/hour.
    At the moment I am looking around to see what is available and at what prices. I have a couple of lamps on test in a workshop to see how they stand up to normal working conditions (I converted a weatherproof HF fitting to take the LED tubes when the ballast went pop) and so far (8 months on) there doesn't seem to be a problem. The most noticable thing is the LED fitting is not quite as bright as the fluorescent one: normal 6ft fluoro lamps are about 6000 lumens, LED replacements vary between 2500 and 3600 so about half as bright. This may be important depending on what lighting levels are needed for the room. The other thing is lamp colour: generally all our lamps are 'warm white' -about 3-3500K- while most LED tubes are 4-6000k depending on selection. Personally, I find 6000k too harsh and prefer the cooler colours.

    Regarding reliability, that's one reason I'm trying out a set of LED tubes first! Over the past 20 years I've put a lot of high frequency fittings in place of the old iron ballasts and am now finding that the electronic ballasts are starting to fail. The cost of a replacement ballast is not too much less than changing over to LED so that's one reason I am now looking to change over. Ironically, the 'old' fluoro fittings in some sheds which must be knocking 40+ years old are still going strong!

    Quote Originally Posted by boballan View Post
    We converted to LED fittings a couple of years ago. Light units "guaranteed" for 3 years. After a short while - 6 months or so they started to fail. Flickering quite badly, simply failing also....
    One building which houses a museum has about 20 recessed GU10 spotlights. Formerly halogen bulbs I changed them over to LEDs, however the LEDs are almost as unreliable as the halogen and I reckon I get about three fail per year either just going off or giving a 'disco' effect! The problem is the LED driver built in to the lamp and I am considering trying to fit a central driver to power all the lights instead of having each connected to the mains. I've found a supplier for high power 12V drivers and have had one running now for about a year 24/7 feeding some equipment. So far so good!
    Andy
    SL 1st Wellington
    www.wellingtonscouts.org

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    Wow 28 6 foot striplights that's either a huge hall or an extremely well lit one! (We have 16 5 foot).

    Anyway let us know how you get on. I dont know why people always think that LEDs never break and don't get dimmer over time because they always, always do!

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    I think people would expect that LEDs can break, dimming is another issue but the current hype surrounding such "energy saving" devices and their longevity glosses over such eventualities. More environmental care is required for LEDs than other light sources. They are ambient temerature sensitive - i.e. if they are fitted in a grid type ceiling and the ceiling is insulated it is essential that the rear of the LED unit is kept free to the atmosphere or else it overheats and fails. Still haven't bottomed how to dispose of faulty units.

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    Quote Originally Posted by Dr_Pepper View Post
    Wow 28 6 foot striplights that's either a huge hall or an extremely well lit one! (We have 16 5 foot).

    Anyway let us know how you get on. I dont know why people always think that LEDs never break and don't get dimmer over time because they always, always do!
    14 sets of 6ft twins in 7 ceiling bays. The hall is about 18m long.
    The actual LEDs are quite robust, it's usually the driver which goes pop.

    Quote Originally Posted by boballan View Post
    I think people would expect that LEDs can break, dimming is another issue but the current hype surrounding such "energy saving" devices and their longevity glosses over such eventualities. More environmental care is required for LEDs than other light sources. They are ambient temerature sensitive - i.e. if they are fitted in a grid type ceiling and the ceiling is insulated it is essential that the rear of the LED unit is kept free to the atmosphere or else it overheats and fails. Still haven't bottomed how to dispose of faulty units.
    Many lamps are temperature sensitive, fluorescents especially don't like cold. Most of the issues with mains-fed LEDs is down to heat dissipation from the driver unit: some cheapo drivers fitted to some makes of economy LED lamps have poor quality components or the heat sink is only just enough for normal use and as soon as things warm up a bit they fail.

    A lot of the LED grid fittings that have been going in on recent jobs have remote drivers so no problem covering over the fitting with insulation. I have also found separate drivers stand up to use a lot better: I mentioned before I have had one running for about a year 24/7 in conditions varying from below freezing to over 40C. So far so good!

    As for disposing of LEDS, the WEEE regs apply. Your local recycling centre should have somewhere for old electrical/electronic equipment or electrical wholesalers will be able to dispose of them.
    Andy
    SL 1st Wellington
    www.wellingtonscouts.org

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  11. #53
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    Quote Originally Posted by Sparkgap View Post
    The most noticable thing is the LED fitting is not quite as bright as the fluorescent one: normal 6ft fluoro lamps are about 6000 lumens, LED replacements vary between 2500 and 3600 so about half as bright. This may be important depending on what lighting levels are needed for the room. The other thing is lamp colour: generally all our lamps are 'warm white' -about 3-3500K- while most LED tubes are 4-6000k depending on selection. Personally, I find 6000k too harsh and prefer the cooler colours.
    As an update to this, I have been having a closer look at lighting levels claimed by various LED manufacturers. In particular the BEAM ANGLE of the tube. Taking a standard 5ft fluorescent tube and its LED replacements, the standard tube has an output of 5200 lumens (lm). This goes out through 360 degrees (so useful if you have a basic (open) fitting where the light goes in all directions). LED tube A has an output of 2860 lm but through 300 degrees, LED tube B has an output of 2300 lm through 320 degrees and LED tube C has 1800 lm through 160 degrees. The equivalent outputs for the three lamps through 360 degrees would be A: 3432 lm, B: 2587 lm and C: 4050 lm! (Lighting For Dummies pt 1! ) In other words, of the three choices tube C would give the brightest light to a surface below it, almost as bright as the standard tube it replaced because it directs most of its output downwards, while if I had a mad desire to illuminate the cobwebs lurking in the corners of our ceilings I would choose tube B even though the actual output is lower (and we'd have to put up with the lower light levels). Since we don't have much need for lighting our ceilings I would consider using an LED lamp with a narrower beam angle to replace the old tubes and if you have fittings with diffusers or reflectors the narrower the better. Hope this clears things a bit!
    Andy
    SL 1st Wellington
    www.wellingtonscouts.org

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  13. #54
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    When we replaced one of our strip lights in our house for an LED one we all reckoned it was much brighter than the flourescent tube it replaced. I suspect this is because its a whiter light and given it reflects off a white angled ceiling from behind a beam the reduced beam angle has no effect on the amount of usable light output.

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    Quote Originally Posted by shiftypete View Post
    When we replaced one of our strip lights in our house for an LED one we all reckoned it was much brighter than the flourescent tube it replaced. I suspect this is because its a whiter light and given it reflects off a white angled ceiling from behind a beam the reduced beam angle has no effect on the amount of usable light output.
    Most led lamps come in either 4000k or 6000k colours. Personally, I don't like the 6000k as they appear a bit harsh/blue-y and most fluorescent tubes we have in use at our hq and in some workshops I deal with are 3500k/warm white. I've got a couple of 6ft 3500k led tubes in weatherproof fittings in a workshop alongside the equivalent flourescent tubes and the leds are probably only 3/4 as bright. I expect if I had used 4000k ones it might have appeared brighter.
    Your normal single flourescent batten fitting probably blocks light from about 90 degrees above the tube and unless the ceiling is a perfect reflector it won't bounce back all the light hitting it. The only advantage of having light escaping above the light is that it reduces the contrast between bright working surface and darker ceiling.
    Andy
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    If I can add-- statistically speaking you'll have a sparky in your parent herd. One probably qualified to do a periodic inspection. Ask your parents to find one willing to help answer that question formally(with a report). I don't think there is a requirement to provide a defuser in the 18th Edition wiring regs. I'll get my book out. Besides that, you might turn the tables and ask the HQ management committee to start getting fundraising grants organised to generally improve the lighting whilst you concentrate on generating fun.

    Quote Originally Posted by Richard T View Post
    Our HQ is illuminated with the standard flourescent tube lights, many years ago these had diffusers over them, however as the ceiling is relatively low these used to get frequently damaged, and subsequently the tube used to get knocked out where it fell to the floor and smashed ( usualy during ball games played inside with soft foam balls) this used to be a regular occurrence, they used to look like this ( before they were inevitably damaged/broken)


    As a result the difuseres were replaced with wire mesh guards, quite some time ago ( 12+ years) similar to whats shown below and since then there has been no breakages of the light fittings



    We now have a ( relatively ) new HQ management committee who have undertaken a fire risk assessment, and this is top of the list:

    Is there such a requirement? I would assess it as a far greater risk from damaged fittings /lights as a result of a lack of guarding than from a fire which may burn downwards

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