Lux Levels public buildings?

The Sponge

Can anyone tell me what the legislation lux Levels should be in public areas?

I'm currently working in a building where light fittings are far too bright and some too low.

Lux meter is reading 800 in certain areas, this seems like a waste of energy.

pieface_ie

CIBSE publish "guidelines" of various lux levels for different applications. What is the function of the building you are referring too?

An office is 500 lux.

If the the build you are referring too is a new build the lighting will initially be above the guideline value as this is where maintenance factors are applied. The lighting level will reduce to a acceptable level as time goes by.

2011

+1 to what pieface says

I would also add:

1) The lux reading is an average, so directly under a light you should expect to get a higher reading

2) Lux levels are calculated for the "working plane". In an office this is desk level (about 900mm). For emergency lighting this is floor level.

muff03

+1 to both, you'll pick the guides up handy enough on pdf online.

The Sponge

Thanks guys,

The lighting system is controlled through DALI (Digital Addressable Lighting Interface) and the lighting has the flexability of dimming to the appropriate level.

I have checked certain meeting rooms in the building from the desk level and between light fittings rather than directly beneath and some lux levels are as high as 1200. This can be greatly reduced to save energy and would be less strain-full for workers.

I'll look through CIBSE and try to acquire some more accurate info.

In the mean time If anyone has narrowed down tips please drop us a message.

Thanks again

Energysavers.ie

Your right! What a waste of energy, and that's most likely 800 lux even before the sun comes in the windows. On a new build design consultants should allow for daylight linking / harvesting in their budget the payback is in the energy bill for the client for years to come. ( Ie:maintain a constant light level on the working plane by the use of dimmable ballasts in the fittings). The technology is there, we are using them on a lot of school projects. I would suggest a combined presence detector is used also, even more savings to be made!

The Sponge

Dali Ballasts are dimmable and and can be controlled with constant lighting control devices (KNX/EIB) compatible. Some rooms throughout the building have no daylight so there is no need.

Its just a case of finding out the correct legislation lux levels for specified areas.

Big problem with these devices is the price and the payback period sometimes dose not seem worth while. Hopefully more accurate calculations can be made once I find out the correct lux levels.

Stoner

the position of the light sensor is very important too, the sensor may be a "dark" place it will be too bright on the desk, for a cellular office some systems recommend that the sensor is just about over the desk, but if people move the desk then the control methodology goes out the window.

The systems rely on the correct amount of feedback. Some offices require 800-1000 Lux at the desk for detailed work. The system can be addressable but not dimmable, i.e zoned , on time clocks, feed back per fitting etc but without the facility to compensate for daylight.

The Sponge

@ Stoner, what system are you talking about?

Stoner

The Sponge wrote: »

@ Stoner, what system are you talking about?

With respect to what part of the post.

Stoner

well the DALI ballast will dim and handle on off control. They are more expensive. Standard HF on off control ballasts don't cost as much as DALI but don't dim.
In some rooms there is no need for dimmable ballasts, or for every fitting to have a dimmable ballast. Say we have a room with three rows of fittings, it's possible the only the outer and middle row need to be dimmable, so the other fittings will be either on or off while the fittings that can gain from daylight will dim.

One of the philips lighting control systems recommend that sensor is placed over the desk for small offices, and has other placement recommendations for larger open plan office.

If there is a room with areas that never get much help from daylight those areas need only be controlled by on/off sensors, on a seperate "circuit" in the same room a different unit will detect movement and allow daylight feedback control.

So if there is a sensor that can detect movement and daylight that is connected to a row of fittings that has DALI dimmable ballasts this sensor must be positioned in so it not only picks up movement but the daylight too, you may need two units in some cases.

So some systems have a mixture of addressable and addressable dimmable fitting on them.

I like standalone zoned dimmable HF lighting control systems, not linked to a central brain. Each zone is programmed for a set lux level and works away on its own, so there are less maintenance issues. If the distribution boards are set up with a standalone lighting section a modbus power usage meter can be installed to monitor the power used per floor.

Lighting control sytems can be great if maintained properly, but in many cases the people looking after them change and the proper training and handover procedures don't happen. So IMHO the best solution is standalone system zoned into areas with daylight dimming and on off conrol, obviously there will be cases where the lighting control system comes into it's own, but these smaller systems are well set up and can be set up in the factory before they get delivered to site, the sensors just need to be in the correct place.

Dardania

It sounds like the lighting installation wasn't well designed, if you're experiencing pooling like that.

Consultants design for an average lux level (as pieface_ie says 500 lux for an open plan office, measured at the workplane) but you also have to take into account the uniformity (which is the ratio of the lowest lux level to the average or max) - basically the closer your uniformity is to 1, the more even your lighting will be. Here's a table of lux levels: http://www.seai.ie/EnergyMAP/Resources_tools/Template_Energy_Use_Cost_Savings_/Table_of_recommended_lux_levels/ and I'd generally want to see uniformities above 0.6 as a minimum

To get better uniformity, you must use more lighting fittings, with less light out (to give a more balanced output) but the average office light fitting would be circa €200-€250 each, installed, so there's a cost benefit to having a less uniform lighting installation.

Lighting controls & dimming can help in your case probably, especially in daylight linked areas, but it's not the solution - if you dim the deep plan spaces, the same lack of uniformity will occur, just at lower lux levels...

It's my experience that lighting controls are rarely properly commissioned in offices, mainly because it's the last thing for the electrical contractor to do, and he has more pressing snags to complete before he can get opinion of compliance... I also notice there is a general lack of expertise out there in sparks, who are great at distribution and general services wiring but commissioning of an integrated system wouldn't be their thing (is the light on? If yes, he's done)

Do you have a lighting control specialist available to do the commissioning? Also, maybe ask your consultant what lux level & uniformity the office was designed to.

2011

Dardania wrote: »

I also notice there is a general lack of expertise out there in sparks

This is because that type of work is not normally within their scope.

On large projects the electrical contractor would install as per the design provided by others (generally a consultancy). The design would be typically be provided by layout drawings, cable block diagrams, and termination drawings.

Although commissioning support would often be provided by an electrical contractor the commissioning would not be within their remit.

Dardania

2011 wrote: »

This is because that type of work is not normally within their scope.

On large projects the electrical contractor would install as per the design provided by others (generally a consultancy). The design would be typically be provided by layout drawings, cable block diagrams, and termination drawings.

Although commissioning support would often be provided by an electrical contractor the commissioning would not be within their remit.

spot on correct - it's not within the elec contractor's expertise, but often it is (and should be) in their package...My opinion it would be madness to run a project where the lighting controls isn't performed in some way by the elec contractor...either by them taking in a lighting controls specialist, or performing it themselves. If they perform it themselves (to save money) they have to be capable of it...

The Sponge

With KNX Dali systems usually the electrician just does the installation which is very simple. All Dali ballasts are just looped out and a certified KNX engineer does the commissioning.

Big thank you to Dardania for the table of lux levels. Just what I wanted.

Stoner

2011 wrote: »

This is because that type of work is not normally within their scope.

On large projects the electrical contractor would install as per the design provided by others (generally a consultancy). The design would be typically be provided by layout drawings, cable block diagrams, and termination drawings.

Although commissioning support would often be provided by an electrical contractor the commissioning would not be within their remit.

True, but it's going to have to come into the scope. Approx 90% of the UK projects I have seen have these systems, the OP never pointed out that this was a KNX system, but as we all know Dali and KNX are not linked there are many systems that work with Dali ballasts. Once more government projects come on board this will be more of an issue IMO, it will become even bigger if we follow the Part L requirements for planning permission like the UK have, forcing developers to meet strict standards of energy efficiency. I don't know why we dont have that yet as it's causing a skills gap for Irish engineering and craft people.

You can go to a supplier now and give them a set of drawings and each room will be planned out, you can be supplied with a lighting control module and all the fittings and detectors are preflexed, the position of the detectors is marked on the drawings too, the supplier will commission.
There is no need for a consultant or a very clued in electrican to have much involvement.
Most of the issues come with guys trying to be too tricky with the BMS IMO, that is why many people now don't link them over and above energy monitoring as they cross into H&S issues and simply confuse the end users.
Look at the amount of government buildings with an expensive lighting control system that you drive past at night and there are still lights on in empty offices?
IMHO in many cases you only need daylight compensated light when there is someone in the building, after that it's off. Sure there are situations where you will need more for cleaning, security or glare but in many cases the above holds.

The whole area has been largly deskilled and simplified with digital control allowing for one single flex to link a LCM to a fitting to control power and switching level.
Currently we have a project with about one paragraph describing the lighting control requirements, CIBSE - 350Lux - .8 uniformity- on/off and daylight control, energy monitored to project BREEAM requirement of "very good". That's all that is required.
I rememeber working on analoge systems where there was a blue klik fed via an ELV conduit to an ELV trunking for the analogue control for ballast dimming , along side a white or red kilk on a 220V conduit. Very expensive installation, a nice job at the time but so much easier to do now.

The Sponge

A lot of interesting knowledge there Stoner however you have stated that "as we all know Dali and KNX are not linked".

I specialise primarily in KNX and Dali and 4 vast projects that I have worked on so far we have used the Siemens Dali Gateways that connect onto the KNX bus line. It is very flexible and commissioned through ETS professional.

http://www.knxshop.co.uk/catalog/Catalog.aspx?Part=SIEMENS_KNX/DALI_Gateway_N141&NavID=003-090-1146-SIE5WG11411AB01

We also do maintenance on the completed projects. For example when the electricians install additional lighting or replace defective ballasts we can commission it remotely.

System is monitored through a head end as well.

Stoner

Sponge I stand by the comment. I was making the point that there are options for people, dali ballasts are compatible with any DALI compliant lighting control system, KNX, Philips, Helvar etc.

The original post asked what could be considered to be a general question about lux levels, we didn't know initially that you specialise primarily in KNX and Dali systems, if I'd know that I would have been more brief in my post

Now we have a post on boards tagged as "Lux Levels public buildings" as we work our way through the post we end up with a user who can maintain such systems.

I have to be on the watch for potential shills here too, I'm sure you understand.

Going to shut this one down now as the OP got the information required.