Lighting Levels (design)

May 03, 2004 8 Replies

Does anybody have a guide to designing light levels .... I have searched around Googgle ... found articles on street lighting design, lighting for hen houses etc. ... but not much on how to figure out how many lights you need in a given room & wattage etc.


The immediate requirement is to decide on size & number of fluorescent fittings for a double garage (wired for 4 light fittings), and for utility and then a store room.



A guide I did find tells me I need an Average Lux of 500 (50 ft candles)


How does this relate to number of watts per sq m (or similar guide) for choosing fluorescent lights ?



There also seems a number of standard units ... ft candles, lumens, candella, etc.


I thought I was getting somewhere .. OSRAM have a design CD ... which gives a free programme DIALux, but I can't seem to get this working for fluorescents... tried to add the Phillips data files without success.


Rick


If your design is for professional application, you need to be aware of the CIBSE Guide & Recommendations. (How you translate their figures into no. of tubes , wattages, etc. from scratch I have no idea, but the major suppliers have guides which seem quite accurate.) One aspect is that fluorescent tubes get dimmer during their life, and designs should take this into account. We used quite a bit of local task lighting to raise the light level where it really mattered without incurring the expense of having high levels everywhere. Beware of tubes giving stroboscopic effects which may be important where rotating machinery is in use.

For your immediate need the simplest is to ask what people have done and found comfortable. Its going to vary a fair bit according to perference of course. I would suggest 4x 4' tubes in the double garage, or even 3x 5' if money's that tight.

Other rooms who knows, depends on size, type of lighting wanted, uplight or downlight, wall colour, carpet colour, and what you want to do in there, ie retrieve stored goods, work all day, fake picassos, etc. :)

There is one thing I would always suggest: having a multiple gang switch with each switch controlling 1 or 2 lights. That way you can use whatever lighting you feel like day to day, and it achieves 2 things:

  1. much reduced energy use
  2. much reduced run costs - which pay back the extra cost in well under a year
  3. it is self correcting for errors in amount of lighting installed.
  4. and it is much more comfortable on the eyes, as what feels right varies a lot through the day.

Oh yes, dont just stick the fl lights on the ceiling, that looks so crap and can easily be done properly. Even for a garage I'd use shelf fitting rather than the traditional wally approach. If youre willing to put an extra hour of work into it then trough fitting is best.

And finally, do get the right tubes with fls. For a garage anything will do, but really avoid things like cool white, 4500K and similar, those are the tubes that have given fl lighting such a bad name. 3500K would be ideal for garage, but the older lower CRI ones like warm white, daylight, etc would also be quite acceptable there.

Tell me if this makes no sense to you :)

Regards, NT

If it's any help, in my 28' x 13' garage I have 4x 8' tubes and 2x 6' tubes and I find the lighting is fine for working under. Don't know what type of tubes they are - just as they came from the electrical wholesaler. All switched in 2 circuits for each half of garage.

Alan.

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In article , Malcolm Stewart writes

Yes where would one find their tables.

They go along the lines of: close inspection work - x Lux Living space - y Lux scrunching machine space - z- lux

I was looking on the CIBSE website for this (and also air changes/hour tables) the other week but couldn't find them.

....

They can sell them for an inordinate amount of money in book form. Why would they want to put them on a web site for free? OTOH your local library might have a copy in their reference section.

Colin Bignell

Full marks to HMG for rejecting this approach and making all Building Regs, Acts of Parliament etc foc - or, more correctly, free at the point of need.

In article , Tony Bryer writes

HMG seem to have quite a scam going by introducing regulations which we normally only hear about after the fact and then requiring us to buy them from HMSO, HSE etc.

Acts of Parliament are available free? Great I'm taking a NEBOSH exam next month and wanted to read applicable acts. Finding them will be a different matter. Too much commentary not enough of the actual regulations available from HMG's sales outlets, sorry departments.

Hard to believe but true:

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since 1995 (IIRC) available

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