Workshop Lighting

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19749106#p19749106]jimothy78[/url] wrote:

Bit of an odd one this, and not sure this is necessarily the best forum for it (so admin feel free to move if you think it would be better elsewhere), but here goes:

My garage/workshop/man-cave currently has two standard bayonet-type light fittings, in which I'm running the most powerful fluorescent bulbs I can find (supposedly each "equivalent" to a 100W incandescent bulb, but I'm not convinced).

Anyway, I'm toying with the idea of fitting batten light fittings instead to give more and better-spread light, and at the same time wondering if I can offset some of the increased power consumption this would normally entail by using LED "tubes" instead of fluorescent.

The only problem I'm having is working out what power of tube (and therefore size of fitting) I'd need to go for. I've seen it stated somewhere that LEDs produce twice as much light for the same power of fluorescent tube, but can I make a direct comparison between the power of straight fluorescent tubes and the existing loopy-bulby things?

Any hints/tips/rules of thumb? Any useful sources of information or experiences?
Thanks in advance

you need to look at the output in lux, not the input in watts. you wont have so many fittings that the efficiency is anything more than an academic point. then its really about placement and the reflective capabilities of the surfaces. Paint the walls and floor white that will increase the effectiveness of the lighting considerably.

You can get a light meter for a few quid and measure what you have where., you need about 50 lux just to stop you walking into things and circa 2000 for very fine detail work.Tthe most cost effective way is to set up a reasonable standard of back ground lighting ( say 700 lux) and then put source lighting ie a spot light over your work bench etc

Here is some info

http://www.engineeringtoolbox.com/light-level-rooms-d_708.html

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19749294#p19749294]jimothy78[/url] wrote:

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19749282#p19749282]brianbee[/url] wrote:

you need to look at the output in lux, not the input in watts. you wont have so many fittings that the efficiency is anything more than an academic point. then its really about placement and the reflective capabilities of the surfaces. Paint the walls and floor white that will increase the effectiveness of the lighting considerably.

You can get a light meter for a few quid and measure what you have where., you need about 50 lux just to stop you walking into things and circa 2000 for very fine detail work.Tthe most cost effective way is to set up a reasonable standard of back ground lighting ( say 700 lux) and then put source lighting ie a spot light over your work bench etc

Here is some info

http://www.engineeringtoolbox.com/light-level-rooms-d_708.html

Thanks for that.
So based on a "mechaincal workshop" level of 750lux, I'd be looking at about 11250 lumens needed to illuminate my 15sqm garage?

What I don't understand is how you can talk about the light "output" of a light fitting in lux, though. Surely unless you know the area being illuminated, you can only measure the light output in lumens? :?

lumens is what is emitted by the fitting, lux is what hits the surface. A lux meter gives you a spot lux reading based on the average that the sq m you measuring in, is being illuminated

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19749327#p19749327]jimothy78[/url] wrote:

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19749321#p19749321]brianbee[/url] wrote:

lumens is what is emitted by the fitting, lux is what hits the surface. A lux meter gives you a spot lux reading based on the average that the sq m you measuring in, is being illuminated

Yep, got that, but earlier you said:

you need to look at the output in lux, not the input in watts

Which seemed to suggest that light sources can have an output stated in lux - if this is the case, then is this based on an assumed illuminated area, or perhaps an assumed height above the illuminated surface?

There are two inputs and two outputs

first, watts in to the fitting, lumens out, giving you the efficiency of the light
then

input-lumens into the room, with lux at any given point as an output. giving the efficiency of the lighting system design

Then its a question of where you want to plug in to the coefficients.

In your case, you have an existing system which doesn't meet your needs. So to my mind the most important output is the light levels you currently have in the room, that is the LUX reading.

If you remember I said get a light meter and measure what you have( at various points in the room. So you may find you have an ambient light level of 500 lux ? which will be more than sufficient to locate your bike, find an allien key and adjust brake lever. But will be woefully short if your doing some fine detail work.

You would then work backwards and say I need an additional light source in this area of the room. Say the work bench of say 3sq meter of an additional 1000 lux. How many Lumens are required to acheive that = ?. Answer- I will buy a spot light or two

If you start from the lumens end off things and design a fresh system on paper, your going to have to carefully consider the positioning of the light fittings, their height and orientation to each other and to work stations and find the luminescent of the wall surfaces. All of which effect how many lux are available for you to see what your doing at any given point in the room

The biggest problem when people go for very BRIGHT lights, is you end up working in your own shadow, which makes it worse than before

Nb before you start, buy some fresh tubes as they can loose 60 or 70% of there brightness over a couple of years and white wash the walls. that may all but solve your problem

Here is more info if your designing the whole system

http://sustainabilityworkshop.autodesk.com/buildings/measuring-light-levels