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how bright can the illuminated sign be?
Yes, I know that there is already an area devoted to sign lighting, but this is somewhat different.
One subject where I have had more queries than most from sign makers concerns the brightness of signs. The question is often asked in planning applications and many of them do not know how a rough figure may be calculated.
However, this is not the point to be covered here. The bible on sign brightness – used by most local authorities – is the ILE report No5 "Brightness of Illuminated Advertisements". The second edition of that report has been in used for a number of years, and its recommendations for maximum sign luminance are readily complied with – no real problem.
Howver, the third edition has recently been published and this contains major changes in maximum sign luminance. For the first time since that edition was published, I was carrying out some calculations for a sign company and realised to my horror that their are problems with the requirements.
It would seem that it now virtually impossible to build, say, a traditional aluminium box fascia, with an opal acrylic face, and with normal fluorescent lighting, and achieve a surface luminance within the limits specified in the third edition. I have vented my spleen in an article due to be published in Sign Directions in April. Full details of my concerns can be found there.
The point about this note is to warn you of the problem and to ask if any of you have heard of planning permissions being turned down as a result of the new limits.
The BSGA are aware of my concerns and will no doubt be taking up the matter urgently with the ILE – it is to be discussed next week at their Technical Committee meeting. Once again, any contributions will be much appreciated.
Regards
Don
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16 Replies
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Well as of yet we have never been asked to provide any figures at all !!!
Our most recent project involving halo lit letters using LED lighting recieved no attention to how bright was it going to be at all from the planning office.
Maybe i have been lucky but in 16 years of sign manufacture i cant ever recall having to provide any figures at all for luminence of signs.
STRANGE !!
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Where do you source your LEDs from paul, and what type/ voltage/ mcd etc. are they mate……..
I’ve just finished a job similar to the one you spoke of but I need to tweak it a little, maybe abb some more LEDs….also what spacings do you use between LEDs and how do you fix them to the backs of the letters?
Cheers
Joe -
are you there Paul???
Joe -
Don’s point about sign brightness is an intriguing one. I have noticed a trend in recent years of increasing brightness in fluorescent illuminated signs. (I put this down in part to the increasing adoption of triphosphor tubes and HF control gear.) I wonder if the new recommendations in ILE5 ed3 might not be the result of a reaction against this and increasing concerns regarding light pollution?
My belief is that it would be much easier to complain against edition three if we at least complied with edition two, which I know for sure, we increasingly don’t. (I have reports of sign box users requesting units “as bright as possible”.) My fear is that unless we deal with this issue now, one day, brightness will be actively policed and Paul’s 16 carefree years will come to an end.
Unlike Don, I don’t believe that obtaining the right brightness is necessarily a problem. Some of our more responsible customers have masked tubes to obtain stripe free results at modest brightness levels. Others have employed dimming ballasts. Still others have started to use special, sign ballasts with cost-effective results. (They permit lamps to be daisy-chained like neon, running more lamps at lower current.)
As for LEDs, I doubt they’ll cause a brightness problem for quite some time…..
As a PS I’d like to say this is my first post here. It’s great to have somewhere to sound off about these things. I always feel that knowledge is a little like manure….it’s not much use until its spread around. However, if I start spouting BS do let me know…
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I guess what narks the planning is when some fool wants to put all sorts of lit rubbish up with disreguard to designing with lighting in mind….
its a good thing that there showing interest, but maybe they also should police the rubbish and dangerous stuff you see hanging over heads in the streets
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hi phil
great to have you on the site mate..
thanks for taking the plunge and getting stuck in..look forward to seeing more posts from you! its always good to have a few pros from this side of the trade to quiz about certain aspects of lighting and the like. 😉
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I think you may be wrong about LEDs there
Keep an eye on the ”show us yours” gallery to find out more
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quote :maybe they also should police the rubbish and dangerous stuff you see hanging over heads in the streets
i agree paul.. a bit more should be done about the cowboys out there doing this type of work.
the last sign i took down tnight was a large neon one. not being clued-up on this side of things but know a bit i thought it was made pretty well.. stood up on the ladders and looked down the back. the whole things was blackend by a fire caused by faluty wiring i guess… makes you wonder 🙄 -
I give up. 😥
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What you giving up on
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Quick Paul before Joe does something drastic and we never hear from him again
Joe said:
Where do you source your LEDs from paul, and what type/ voltage/ mcd etc. are they mate……..
I’ve just finished a job similar to the one you spoke of but I need to tweak it a little, maybe abb some more LEDs….also what spacings do you use between LEDs and how do you fix them to the backs of the letters?
Cheers
JoeJohn
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i think he means he gives up on asking this mate! 😉
quote :Where do you source your LEDs from paul, and what type/ voltage/ mcd etc. are they mate……..
I’ve just finished a job similar to the one you spoke of but I need to tweak it a little, maybe abb some more LEDs….also what spacings do you use between LEDs and how do you fix them to the backs of the letters?
Cheers
Joe -
OK OK OK wind ya neck back in !!!!!
You wanna know to much all at once
LEDs are from LUXEON (www.luxeon.com),they are luxeon stars, 24v phillips drivers, cant remember but they hurt your eyes to look at (really!!)
average space between each one is about 150mm (they are single lamps on an aluminium PCB)
They are fixed to the letter by a thermal transfer tape from 3m
They are coated with a conformal coating
Each one of the fraser letters has 18 lamps in it, they took about 20 mins each to fully lamp up (compare this to neon in terms of installation time)
roughly 120 quid to lamp a letter up with a driver, ready to goWant more ??????
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Sorry Paul! 😳
Firstly, thanks for the info for the LEDs.
I was a bit fed up when I posted “I give up”, spent most of the day getting signschool set up, went back to the office ( where my cutters comps,etc. live) to find that the landlord has put one of those intercom things on the front of the building and the monkeys who fitted it buggered up the locks so I couldn’t get in to cut a job I promised for delivery this morning…..
bloody builders (:) .
Thanks again mate
Joe -
The limits for sign luminance in the third edition of ILE Reopt No 5 are defintely too low for practical purposes. Have you looked at the data sheets produced by ICI platics (now Lucite). These list the surface luminances for different plastics materials and with different spacing for fluorescent and cold-cathode tubes. Unless that tubes are placed impossibly far apart, there is no possibility of getting anywhere near the new limits. Yes, I know that you can reduce tube brightness by various dimming techniques but, in the real world, the competitive environment means that sign makers have to keep things simple. Standard fluorescent lamps in plastic faced aluminium boxes is what we nearly always use.
The problem came to mind when I was was carrying out calculations on individual letter signs for a major sign company. Similar signs calculated last year were within the limits of the then second edition. Signs this year are well above the limits in the third edition.
My other beef is that there is no differentiation between sign sizes up to a face area of 10 m2. This means that a tiny projecting sign has to be equally as dim as quite a large illuminated fascia. In the second edition, it was mentioned that sign luminances below 200 Cd/m2 were considered too dull and ineffective. In the latest edition, they quite happily quote 100 Cd/m2.
The next edition of Sign Directions magazine is about to be published. Full details are in my article in that issue.
Regards
Don
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Don,
I completely agree with you on the wrongness of the third edition, both in brightness levels and in failing to distinguish between intermediate sizes. I maintain, however, that there is an increasing preponderance of overbright signs even given edition two levels. Unsurprisingly these are generally larger signs.
I’m still not sure I agree with your point regarding the lack of ease of running fluorescent tubes at lower brightness. Having done a lot of work of late with American ballasts and lamps, I was impressed by the range of choice in rating and the understanding that (with no electrode maintenance!) lamps can be run safely over a wide range of currents(down to 50% in some cases). In the UK and Europe, lamp and ballast manufacturers pay little attention to the needs of the sign industry and produce products and data related to standardised light outputs from luminaires only.
The recent introduction of sign ballasts for fluorescent lamps into the UK permits a choice of (fixed) currents for standard lamp types. As a handwaving example it permits the operation of two 100W tubes at 50W each on a single 100W ballast. The advantage of running more lamps at lower brightness off one ballast can be traded for correct brightness signs with no hot spots or thinner sign boxes etc.
The argument aginst ed.3 I feel should not be solely about impracticality. Do-gooders don’t respond well to that sort of thing in my experience and it doesn’t secure things for the future. The argument should be that the light levels proposed are, simply, stupidly low. They will succeed only in making the signed environment dismal and unattractive for all.
I greatly look forward to your article. Meanwhile, the kids and a large bar of Toblerone are calling me. I must obey….
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