Luminous Efficiency

[sambuca2907]

Hi all - Very new to this site, wondering if someone could help me!

"All lamps must have a luminous efficiency greater than 40 lumens per circuit"

Can anyone help/explain the above statement?

Thanks
Adam

 

[johnnyb]

Light is measured in lumins , and therefore if you have seen this in a spec or something they are asking you to acheive 40 lumins minimum, so the light fittings you propose say must have 60 lumins at desk height level for an example, which i think is the norm in an office enviroment, usually with cat 2 diffusers.

 

[sambuca2907]

Thanks for the response - How do I work this out from Watts/Input Voltage?

Have had a look on several wholesaler websites and they don't show a lumin value on the lamp/downlight spec. Just Wattage and Operating Voltage.

 

[johnnyb]

We usually use a lighting rep at our wholesalers, they are only to pleased to assist, and if its a big job and its already been to say New and Eyre they will already have the spec anyway, as this means you are all quoting the same then.
They will ask you the height and area you wish to cover, they have the computer soft ware mate, 2 mins for them.

 

[sambuca2907]

Thanks for that - will pop down to CEF and see if they have the software.

 

[andyb]

You are being asked to install fittings having a luminous efficacy greater than 40 lumens per circuit-watt.
This is required under part L of the building regs for a certain number (roughly 1 in 3) of new rooms in extensions and new houses.
Low enegy downlights come into this bracket as do fluorescent fittings. If they ask for ceiling roses, you can get lampholders that will only take low energy lamps.
If unsure, ask your supplier to talk to the tech department of the light manufacturer.

 

[sambuca2907]

I have just found this in the electricians guide to the building regs book - page 134.

Baisically says that you cannot use edison screw or bayonet lamps!