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Author Topic: Emergency lighting system lighting levels  (Read 5714 times)

Offline Tom Sutton

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Emergency lighting system lighting levels
« on: September 23, 2010, 10:54:47 AM »
I received the following enquiry and are at present I am trawling through BS 5266 can anybody help? My first impressions are, they should be contacting the designing company to amend the specification.

Quote
We are not the designer of this emergency lighting system either from a lux level or positioning angle. We are supplying and installing to a recognised consulting company, proficient with emergency lighting systems.
 
We are installing hand railing into several areas including a stairwell we have been asked for 3 hour duration maintained emergency lighting within the hand rail. The actual light fittings are LED inserted into the hand rail at predetermined distances to give a desired lux level in both running and emergency. The nature of the light fittings is they only have one standard light level they are 24vdc in operation in normal operation the lights are powered from a driver. In emergency they are powered from batteries” I believe all this is installed and certified to BS 5266 AND BS7671.
 
With exception of the lux level in the emergency duty being too high the LED lighting have the same light output in both duties the areas with the handrail lighting is in the region of 30 lux while the surrounding areas are in the 2 lux level giving us a uniformity problem.
 
The consensus of opinion is to fit a dimmer in a 3 hour enclosure, fitted into the battery line to reduce the lux output levels in the emergency duty only.

The actual question is, if I fit this dimmer, will the system still comply with BS 5266


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All my responses only apply to England and Wales and they are an overview of the subject, hopefully it will point you in the right direction and always treat with caution.

Offline Galeon

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Re: Emergency lighting system lighting levels
« Reply #1 on: September 23, 2010, 11:55:35 AM »
So if maintained they are on all the time not really a good idea to me as you are affecting the service life of the lamp or in this case leds .
Personally i would split these circuits.
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Offline Tom Sutton

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Re: Emergency lighting system lighting levels
« Reply #2 on: September 23, 2010, 02:29:00 PM »
Galeon

I don't think he has any choice and his main concern is the uniformity of illumination in the emergency mode. Also if he uses a dimmer will it be in accordance with  BS 5266 p1 and he will also need to consider BS EN 1838 & BS 5266 p7 as well?
« Last Edit: September 23, 2010, 02:37:51 PM by Tom Sutton »
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All my responses only apply to England and Wales and they are an overview of the subject, hopefully it will point you in the right direction and always treat with caution.

Offline lyledunn

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Re: Emergency lighting system lighting levels
« Reply #3 on: September 23, 2010, 06:14:35 PM »
Uniformity according to BSEN 1838 is 40:1 max. Would appear that this installation meets that criteria.
Regards,
Lyle Dunn
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