We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

(No dimmers are involved only on/off switches.)

In article ,
EricP writes:
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

"Daylight" tends to mean high colour temperature (5500 - 6500K).

There are often two problems with this when used for artificial
lighting:

The intensity is nowhere near what your brain expects for this
colour temperature, so it looks wrong and makes colour perception
(particularly in the reds) more difficult. Raw meat preparation
is the classicly bad match for such a situation.

Some of these high colour temperature LEDs have poor colour
rendering properties. Again, if discrimination by colour (not
racial discrimination;-) is part of the job, it could be that
this is now much harder to do.

What is her job?

Another potential issue - if the lamps are dimable on regular
dimmers (even if not used in this case), many such LED lamps
flicker at 100Hz. That's not a problem normally, but if you
are looking at things which move under 100Hz strobe, it might
be.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Flicker or perhaps a spectrum problem. Its surprisingly easy to fool the eye
that light is white when it is actually not.

Brian

--
From the Sofa of Brian Gaff Reply address is active
"EricP" wrote in message
...
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

(No dimmers are involved only on/off switches.)

In article , EricP
writes
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

(No dimmers are involved only on/off switches.)

She'll need to wear sunglasses until the management realise their
mistake. Seriously, they'll get the message eventually and the sunnies
will help reduce the effects in the mean time. Don't vocalise too loudly
about the problem but if asked, do mention that the glasses are needed
to stave off blinding headaches that started when the new lamps were
installed.

--
fred
it's a ba-na-na . . . .

On 01/05/2015 09:28, fred wrote:
In article , EricP
writes
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

(No dimmers are involved only on/off switches.)

She'll need to wear sunglasses until the management realise their
mistake. Seriously, they'll get the message eventually and the sunnies
will help reduce the effects in the mean time. Don't vocalise too loudly
about the problem but if asked, do mention that the glasses are needed
to stave off blinding headaches that started when the new lamps were
installed.


You can get sheets of daylightwarm white converting filters quite
cheaply. Might be worth a try, if only as an experiment

On 01/05/2015 10:22, stuart noble wrote:
On 01/05/2015 09:28, fred wrote:
In article , EricP
writes
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

(No dimmers are involved only on/off switches.)

She'll need to wear sunglasses until the management realise their
mistake. Seriously, they'll get the message eventually and the sunnies
will help reduce the effects in the mean time. Don't vocalise too loudly
about the problem but if asked, do mention that the glasses are needed
to stave off blinding headaches that started when the new lamps were
installed.


You can get sheets of daylightwarm white converting filters quite
cheaply. Might be worth a try, if only as an experiment

I converted *all* of our bulbs to daylight bulbs and the lighting is so
much clearer. I compared the old bulbs with the daylight ones and the
old ones looked positively yellow. A dramatic difference and improvement.
None of us have suffered any headaches since I changed them about 6
months ago.

In article ,
EricP wrote:
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

Probably flicker - too fast to be noticeable. Although I'm surprised it's
effected everyone.

--
*Being healthy is merely the slowest possible rate at which one can die.

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...
In article ,
EricP wrote:
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

Probably flicker - too fast to be noticeable.
Although I'm surprised it's effected everyone.

Yeah, bet that isn't anything physical.

Can't think of the word for it, groupthink isn't quite right.

On 01/05/2015 11:11, Rod Speed wrote:


"Dave Plowman (News)" wrote in message
...
In article ,
EricP wrote:
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

Probably flicker - too fast to be noticeable.
Although I'm surprised it's effected everyone.

Yeah, bet that isn't anything physical.

Can't think of the word for it, groupthink isn't quite right.
Mass hysteria?

On 01/05/2015 11:11, Rod Speed wrote:


"Dave Plowman (News)" wrote in message
...
In article ,
EricP wrote:
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

Probably flicker - too fast to be noticeable.
Although I'm surprised it's effected everyone.

Yeah, bet that isn't anything physical.

Can't think of the word for it, groupthink isn't quite right.

Group hysteria probably. A lot of it about apparently

On Friday, 1 May 2015 11:11:52 UTC+1, Rod Speed wrote:
"Dave Plowman (News)" wrote in message
...
In article ,
EricP wrote:
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

Probably flicker - too fast to be noticeable.
Although I'm surprised it's effected everyone.

Yeah, bet that isn't anything physical.

Can't think of the word for it, groupthink isn't quite right.

Theer was a item on the TV a while ago where they tested the taste of red wine under difernt lighting conditions (they did the same with food).
They found that under red light people stated that the red wine tasted better, when under red light the same happened with red meat

http://www.telegraph.co.uk/news/scie...lit-rooms.html

Another test showed that people drank more and for longer under blue light, which was a suprise and most believed that red light made you feel hottoer so would therefor make you drink more, but what they fouhnd was that blue light kept you awake longer giving you more time to drink. This was done in a bar they hired out and on cetain nights they lit the place with differnt colours.

On Thu, 30 Apr 2015 22:48:40 +0000 (UTC),
(Andrew Gabriel) wrote:

In article ,
EricP writes:
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

"Daylight" tends to mean high colour temperature (5500 - 6500K).

There are often two problems with this when used for artificial
lighting:

The intensity is nowhere near what your brain expects for this
colour temperature, so it looks wrong and makes colour perception
(particularly in the reds) more difficult. Raw meat preparation
is the classicly bad match for such a situation.

Some of these high colour temperature LEDs have poor colour
rendering properties. Again, if discrimination by colour (not
racial discrimination;-) is part of the job, it could be that
this is now much harder to do.

What is her job?

It's a social club. Just the usual large room with dormer type windows
and a bar at one end. It has always has quite nice low level lighting
brightening at the bar

What you have said has exactly confirmed the ideas of a sparks that is
a regular and a few others.

Many thanks for your good input.

"Malcolm Race" wrote in message
...
On 01/05/2015 11:11, Rod Speed wrote:


"Dave Plowman (News)" wrote in message
...
In article ,
EricP wrote:
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

Probably flicker - too fast to be noticeable.
Although I'm surprised it's effected everyone.

Yeah, bet that isn't anything physical.

Can't think of the word for it, groupthink isn't quite right.

Mass hysteria?

Yeah, tho there isn't really much mass involved.

On Fri, 01 May 2015 10:55:14 +0100, "Dave Plowman (News)"
wrote:

In article ,
EricP wrote:
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

Probably flicker - too fast to be noticeable. Although I'm surprised it's
effected everyone.

Good idea about that. Hopefully they can get it looked at soon.

"stuart noble" wrote in message
...
On 01/05/2015 11:11, Rod Speed wrote:


"Dave Plowman (News)" wrote in message
...
In article ,
EricP wrote:
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

Probably flicker - too fast to be noticeable.
Although I'm surprised it's effected everyone.

Yeah, bet that isn't anything physical.

Can't think of the word for it, groupthink isn't quite right.

Group hysteria probably.

Yeah, tho hysteria isn't quite the right word either.

A lot of it about apparently

Yeah, that's why the placebo effect works.

One arsehole of a mate of mine has a hobby of pretending
to experience food poisoning when eating out in a large
group of people. Its amazing how many others decide
that they are about to start retching too.

"whisky-dave" wrote in message
...
On Friday, 1 May 2015 11:11:52 UTC+1, Rod Speed wrote:
"Dave Plowman (News)" wrote in message
...
In article ,
EricP wrote:
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

Probably flicker - too fast to be noticeable.
Although I'm surprised it's effected everyone.

Yeah, bet that isn't anything physical.

Can't think of the word for it, groupthink isn't quite right.

Theer was a item on the TV a while ago where they
tested the taste of red wine under difernt lighting
conditions (they did the same with food).

They found that under red light people stated that the red wine tasted
better, when under red light the same happened with red meat

http://www.telegraph.co.uk/news/scie...lit-rooms.html

Another test showed that people drank more and for longer
under blue light, which was a suprise and most believed that
red light made you feel hottoer so would therefor make you
drink more, but what they fouhnd was that blue light kept
you awake longer giving you more time to drink. This was
done in a bar they hired out and on cetain nights they lit
the place with differnt colours.

Interesting. Must get one of those RGB leds and try that myself.

En el artículo , Simon Brown
escribió:

arsehole

Quite.

Another Woddles morph killfiled.

--
:: je suis Charlie :: yo soy Charlie :: ik ben Charlie ::

On Friday, May 1, 2015 at 10:22:07 AM UTC+1, stuart noble wrote:
On 01/05/2015 09:28, fred wrote:
In article , EricP
writes
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

(No dimmers are involved only on/off switches.)

She'll need to wear sunglasses until the management realise their
mistake. Seriously, they'll get the message eventually and the sunnies
will help reduce the effects in the mean time. Don't vocalise too loudly
about the problem but if asked, do mention that the glasses are needed
to stave off blinding headaches that started when the new lamps were
installed.


You can get sheets of daylightwarm white converting filters quite
cheaply. Might be worth a try, if only as an experiment

Its a yellow filter , it`ll just lower output by quite a lot.

Warm white LEDs use a differnt phosphor mix to cool white.

EricP wrote:
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

Sounds like crap, I do not believe it,they need psych evaluation good
fodder for some cult.

(No dimmers are involved only on/off switches.)

On Thursday, 30 April 2015 23:06:47 UTC+1, EricP wrote:
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs
Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Any nasty vapours being given off by the lights or the power supplies? Varnish on circuit boards overheating?

Anything in the building been disturbed? EG Could there be a leaky boiler flue above a ceiling, which has been disturbed to install the lights, and CO is now getting into the workplace?

Owain

On 02/05/2015 11:05, wrote:
On Thursday, 30 April 2015 23:06:47 UTC+1, EricP wrote:
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs
Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Any nasty vapours being given off by the lights or the power supplies? Varnish on circuit boards overheating?

Anything in the building been disturbed? EG Could there be a leaky boiler flue above a ceiling, which has been disturbed to install the lights, and CO is now getting into the workplace?

Owain

I changed ALL of our lights to daylight ones and it's one of the best
things I've ever done. The light is far more pleasant and superior.
We haven't had a headache since the change.

On Thu, 30 Apr 2015 23:06:35 +0100, EricP
wrote:

We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

(No dimmers are involved only on/off switches.)

Just found this:

The Workplace (Health, Safety and Welfare) Regulations 1992:
Regulation 8 requires every workplace to have suitable and sufficient
lighting. The lighting in the workplace, should as far as is possible,
be natural.

and this:

The Management of Health and Safety at Work Regulations 1999
place a duty on employers and self-employed people to assess risks
to health and safety from their undertaking. This will include risks
from lighting.

- Mike

On Thu, 30 Apr 2015 23:06:35 +0100, EricP
wrote:

We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

(No dimmers are involved only on/off switches.)

Also found this:

http://www.digikey.co.uk/en/articles...g-applications

- Mike

On Sat, 02 May 2015 11:08:36 +0100, Bod wrote:

On 02/05/2015 11:05, wrote:
On Thursday, 30 April 2015 23:06:47 UTC+1, EricP wrote:
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs
Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Any nasty vapours being given off by the lights or the power supplies? Varnish on circuit boards overheating?

Anything in the building been disturbed? EG Could there be a leaky boiler flue above a ceiling, which has been disturbed to install the lights, and CO is now getting into the workplace?

Owain

I changed ALL of our lights to daylight ones and it's one of the best
things I've ever done. The light is far more pleasant and superior.
We haven't had a headache since the change.

For 'daylight' I prefer 4000K - 4500K (nominally moonlight in thickypedia).
It is bright and clear without any trace of blueness. So far I've found only
3 lamps in this range: 3W, 320lm; 4W, 600lm and one that I have bookmarked
BCBA to look (the last pint, at 9%, does that to me!).
--
Peter.
The gods will stay away
whilst religions hold sway

On 02/05/2015 17:46, PeterC wrote:
On Sat, 02 May 2015 11:08:36 +0100, Bod wrote:

On 02/05/2015 11:05, wrote:
On Thursday, 30 April 2015 23:06:47 UTC+1, EricP wrote:
We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs
Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Any nasty vapours being given off by the lights or the power supplies? Varnish on circuit boards overheating?

Anything in the building been disturbed? EG Could there be a leaky boiler flue above a ceiling, which has been disturbed to install the lights, and CO is now getting into the workplace?

Owain

I changed ALL of our lights to daylight ones and it's one of the best
things I've ever done. The light is far more pleasant and superior.
We haven't had a headache since the change.

For 'daylight' I prefer 4000K - 4500K (nominally moonlight in thickypedia).
It is bright and clear without any trace of blueness. So far I've found only
3 lamps in this range: 3W, 320lm; 4W, 600lm and one that I have bookmarked
BCBA to look (the last pint, at 9%, does that to me!).

I see.

On 01/05/2015 20:04, EricP wrote:


It's a social club. Just the usual large room with dormer type windows
and a bar at one end.

Are you sure that its the lights and not a duff batch of beer?


--
mailto: news {at} admac {dot] myzen {dot} co {dot} uk

On 02/05/2015 11:08, Bod wrote:

I changed ALL of our lights to daylight ones and it's one of the best
things I've ever done. The light is far more pleasant and superior.
We haven't had a headache since the change.


All my main lights are now daylight LED and I too prefer them. However,
my preference could be age related - as I get older my eyesight is not
as good as it once was and I find that daylight type LEDs give better
perceived contrast and make reading etc. easier.

--
mailto: news {at} admac {dot] myzen {dot} co {dot} uk

On 02/05/2015 18:43, alan_m wrote:
On 01/05/2015 20:04, EricP wrote:


It's a social club. Just the usual large room with dormer type windows
and a bar at one end.

Are you sure that its the lights and not a duff batch of beer?


Yes it does seem strange to get headaches from daylight bulbs. They have
a much better spectrum for the eyes.
It's certainly the first I've ever heard of getting headaches from them.

On 02/05/2015 18:52, alan_m wrote:
On 02/05/2015 11:08, Bod wrote:

I changed ALL of our lights to daylight ones and it's one of the best
things I've ever done. The light is far more pleasant and superior.
We haven't had a headache since the change.


All my main lights are now daylight LED and I too prefer them. However,
my preference could be age related - as I get older my eyesight is not
as good as it once was and I find that daylight type LEDs give better
perceived contrast and make reading etc. easier.

Agreed, many people choose daylight lamps specifically for reading.

"Mike" wrote in message ...
On Thu, 30 Apr 2015 23:06:35 +0100, EricP
wrote:

We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

(No dimmers are involved only on/off switches.)

Just found this:

The Workplace (Health, Safety and Welfare) Regulations 1992:
Regulation 8 requires every workplace to have suitable and sufficient
lighting. The lighting in the workplace, should as far as is possible,
be natural.

Not feasible with that nightclub/bar.

and this:

The Management of Health and Safety at Work Regulations 1999
place a duty on employers and self-employed people to assess risks
to health and safety from their undertaking. This will include risks
from lighting.

There will always be some risk of groupthink/group hysteria.

"alan_m" wrote in message
...
On 01/05/2015 20:04, EricP wrote:


It's a social club. Just the usual large room with dormer type windows
and a bar at one end.

Are you sure that its the lights and not a duff batch of beer?

Its unlikely that all the staff are drinking the beer while working.

On Saturday, May 2, 2015 at 7:31:17 PM UTC+1, Bod wrote:
On 02/05/2015 18:43, alan_m wrote:
On 01/05/2015 20:04, EricP wrote:


It's a social club. Just the usual large room with dormer type windows
and a bar at one end.

Are you sure that its the lights and not a duff batch of beer?


Yes it does seem strange to get headaches from daylight bulbs. They have
a much better spectrum for the eyes.
It's certainly the first I've ever heard of getting headaches from them.

Your mixing up (correlated) Colour Temperature with Spectral Power Distribution, helped by suspect marketing.

On Sun, 3 May 2015 06:38:24 +1000, "Simon Brown"
wrote:



"Mike" wrote in message ...
On Thu, 30 Apr 2015 23:06:35 +0100, EricP
wrote:

We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

(No dimmers are involved only on/off switches.)

Just found this:

The Workplace (Health, Safety and Welfare) Regulations 1992:
Regulation 8 requires every workplace to have suitable and sufficient
lighting. The lighting in the workplace, should as far as is possible,
be natural.

Not feasible with that nightclub/bar.

Why not? It's a workplace, so the 1992 regs apply for the benefit ot
the workers there.
- Mike

"Mike" wrote in message ...
On Sun, 3 May 2015 06:38:24 +1000, "Simon Brown"
wrote:



"Mike" wrote in message ...
On Thu, 30 Apr 2015 23:06:35 +0100, EricP
wrote:

We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

(No dimmers are involved only on/off switches.)

Just found this:

The Workplace (Health, Safety and Welfare) Regulations 1992:
Regulation 8 requires every workplace to have suitable and sufficient
lighting. The lighting in the workplace, should as far as is possible,
be natural.

Not feasible with that nightclub/bar.

Its actually a social club.

Why not?

Because it appears to mostly operate at night and moonlight
leaves rather a lot to be desired in a place like that.

It's a workplace, so the 1992 regs apply for the benefit ot
the workers there.

Yes, but natural light just isn't viable there.

On Mon, 4 May 2015 06:30:29 +1000, "Simon Brown"
wrote:



"Mike" wrote in message ...
On Sun, 3 May 2015 06:38:24 +1000, "Simon Brown"
wrote:



"Mike" wrote in message ...
On Thu, 30 Apr 2015 23:06:35 +0100, EricP
wrote:

We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

(No dimmers are involved only on/off switches.)

Just found this:

The Workplace (Health, Safety and Welfare) Regulations 1992:
Regulation 8 requires every workplace to have suitable and sufficient
lighting. The lighting in the workplace, should as far as is possible,
be natural.

Not feasible with that nightclub/bar.

Its actually a social club.

Why not?

Because it appears to mostly operate at night and moonlight
leaves rather a lot to be desired in a place like that.

It's a workplace, so the 1992 regs apply for the benefit ot
the workers there.

Yes, but natural light just isn't viable there.

You seem to have misunderstood me, the regs don't specify that it
should be actual natural light, although that it preferable, just
close to it and most importantly, not dangerous in any way (such as
causing headaches).
- Mike

"Mike" wrote in message ...
On Mon, 4 May 2015 06:30:29 +1000, "Simon Brown"
wrote:



"Mike" wrote in message ...
On Sun, 3 May 2015 06:38:24 +1000, "Simon Brown"
wrote:



"Mike" wrote in message
m...
On Thu, 30 Apr 2015 23:06:35 +0100, EricP
wrote:

We are LED converted at home and very pleased with them but the place
my wife works have just replaced all their bulbs with Daylight LEDs

Immediately everyone working there has got terrible headaches that
last about twenty four hours. The whole staff from managers down.

Anyone get any ideas about this.

(No dimmers are involved only on/off switches.)

Just found this:

The Workplace (Health, Safety and Welfare) Regulations 1992:
Regulation 8 requires every workplace to have suitable and sufficient
lighting. The lighting in the workplace, should as far as is possible,
be natural.

Not feasible with that nightclub/bar.

Its actually a social club.

Why not?

Because it appears to mostly operate at night and moonlight
leaves rather a lot to be desired in a place like that.

It's a workplace, so the 1992 regs apply for the benefit ot
the workers there.

Yes, but natural light just isn't viable there.

You seem to have misunderstood me,

No.

the regs don't specify that it
should be actual natural light, although that it preferable, just
close to it

The regs say nothing like that. What they actually say is
that it should be natural light when that is possible.

It isn't with a social club mostly used at night.

and most importantly, not dangerous in any way (such as
causing headaches).

There is no evidence that it does cause headaches, just
that they are seeing some groupthink/group hysteria.