Lumens per circuit watt? As per Architects!!

[G_FUNK]

Been pricing up a veterinary practice the lighting as per the specs and drawings state:

"Lighting - To achieve an average efficacy of 85 lumens/ circuit watt using T5 fluoresecents with high frequency ballasts."

And thats it.
Cracked out the newlec catalogue and the LEF figures for t5 lamps runing off high frequency fitting that are switched on and off via a light switch dont even reach an lef of 80 lumens!

hhhmmm im not quite sure what to do any advise would be much needed

regards

martin

 

[i=p/u]

led replacments is close @73 lumens per watt

Aurora T5 4W 288mm Clear LED Tubes - Daylight

 

[i=p/u]

and that took 10 secs s probably is better out there...

 

[G_FUNK]

The problem is to achieve this 85 lumens per circuit watt i could just install one light in each room that has a LEF of 85 lumens this how ever wont light the installation enough for it purpose. So i need to know the levels of luxs that are required for vets and then find a lamp like t8 fluorescent tubes the have a LEF of around 85 lumens and calculate the lux level from there to work out the number of tubes needed in order to work out the number of fitting needed.

 

[dim_bulb]

250- 350 lux get yourself a light meter

 

[G_FUNK]

i have one already but i cant see it helping my price up the job. the building isnt even built its just a field. i need to work out from a very ambiguous spec the number of fittings needed to light the installation. all that is said on the spec is achieve "85 lumens per circuit watt using t5 fluorescent lamps."

t5 lamps dont even have a LEF of any where near 85 lumens even if 4 are used in a modular fitting. There isnt any mention of any lux levels to acheive.

 

[SPARTYKUS]

There's alot of cobblers on some of these plans, put on by the architect and (dare I say it) the BC.

One on my desk now, extension, I quote:
"Inspected and tested in accordance with BS7671:2001"

Smoke alarm in an understairs cupboard (nothing in it)

Also

"....to wire in self contained smoke detectors with battery backup where shown on plan (!), all to comply with BS5446; part 1 alarms linked together on separate circuit and fitted min. 300 from walls or lights"


three things

I never (well, hardly) ever install interlinked smokes on their own circuit. If the circuit trips very often first you know about it is the smoke detector battery has had it. Always on the lights.

Secondly it says "300" - 300 what? cm? I know the answer but....

and thirdly its says 300 from a wall. Well I'm stuffed if I want to fit one to a wall then!!!! (you can)

Thought of a 4th - smoke alarm in the lounge. Right above a woodburner......... Hmmm

and a 5th - loads of lights throught the house (parts not being changed) marked as needing to be changed to energy efficient ones ...... thats not going to happen either!!

 

[mark80]

I don't think it means 85 lumens per watt per fitting. It'll be more like an average over the whole installation! Check out part L of the building regs. I'm sure the minimum is 55 lumens but not 100%

 

[G_FUNK]

I always had the feeling that the architect had copped out on the lighting spec.

I have worked it out using t8 36 watt lamps with a LEF of 91.5 with a room size of 3.7 meters by 4.4 meters to get a lux of 350lx. I get it as follows

350 x 3.7 x 4.4/ (0.8 x 0.6) = 11871 lm

11871/91.5= 130 watts

130/36= 3.61

4 fittings using single tubes

using a maintenance factor of 0.8 and a coefficent of utilization of 0.6. these two figure i am a little unsure how much they can change with diffirent environments.

Any body think this looks about right?

give me down lights in a bathroom or kitchen over this any day!