Just a quick one.

Does anyone have any information about calculating how much light to
"put into" a room? The room in question is 6.5m by 3.1m and will be
used for "conference"-type meetings; round-table discussions and
presentations to small groups of people in daylight and at night time.

The people in question will probably use standard 5ft or 6ft tubes at
least initially. They may, later, wish to change these to something
less industrial or possibly add up/wall lights, but let's ignore that
for now.

Intuitively I would have thought 4 or 6 tubes (1-tube fittings)
switched in banks of 2 or 3 would do the trick - high level of even
light for round-table meetings and the possibility of switching off a
bank or two for use with OHPs etc.

Does anyone have any better suggestions? What about the colour-balance
of the tubes?

TIA

Hwyl!

Martin.

--
Martin Angove: http://www.tridwr.demon.co.uk/

(Martin Angove) wrote in message . com...

Just a quick one.

Does anyone have any information about calculating how much light to
"put into" a room? The room in question is 6.5m by 3.1m and will be
used for "conference"-type meetings; round-table discussions and
presentations to small groups of people in daylight and at night time.


Hi Martin.

Personal preferences vary, ditto colour of walls, level of light
needed for differenr jobs... tough one to calculate. I have studied
approaches to numbers/calculations, but I dont think I'd follow them
to be honest. I cant help thinking someone was trying to
simlpistically sciensce-ify something with too many real world
variables.

Once you've started with an initial estimate its easy to put wires on
the fittings and stick them up temporarily to see what it looks like.

If you want comfort I would really go for 4' not 5'. Personally I'd
start with say 4x 4' fittings for a white painted room that size, with
the tubes pointing up, not down. I.e. either shelf, trough or even
suspecnded fittings. That is one of the most important faetures of any
fl light installation. Unfortunately most are still being installed
pointing down.

Another important is switching: a switch for every light, then you can
make sure you're always comfortable, and not waste money/energy.
Comfort is important in work situations, and is an issue with many fl
installations.

The last important is use any colour of white you like, but _dont_
ever touch cool white or 4500K. As long as you avoid those 2 horrors
anything else is usually fine.


The people in question will probably use standard 5ft or 6ft tubes at
least initially.

6' hasnt been standard for a long time.


Intuitively I would have thought 4 or 6 tubes (1-tube fittings)
switched in banks of 2 or 3 would do the trick - high level of even
light for round-table meetings and the possibility of switching off a
bank or two for use with OHPs etc.

Too high, too little control. But this is all too common, carelessness
design seems to be the done thing with fl lights.


Regards, NT

The ceiling height matters, but say 2.5m.

using 6 off 5' singles with 3500K triphosphor tubes on a 3x2 grid,
longwise dowmn the room, will give about 700 lux across the room at
table level, except for the 2' nearest the walls.

This is a bit bright for what you need, so go for what other posters
have said and use DL's for the table; and 4' tubes.

If the ceiling is much higher than 2.5m then you'll need to consider
louvred fittings to reduce the glare along the length of the room, and
recalculate!

Hwyl dda.