A Question About Lighting Design in Accordance With EN 12464-1

I haven't performed lighting calculations in a very long time. From your description it sounds like you are using the wrong number somewhere in your calculations. Likely candidates are using the on axis luminosity incorrectly, mirror instead of diffused reflector numbers, source spectrum, viewer/lamp orientation. Then there are the real oddball possibilities of the collection of optical illusion effects the eye plays, unexpected reflected light polarizations and who knows what.

Unlike electronic circuit modelling software lighting design using modern lighting software is very simple and works well because lighting design is more tolerant of errors and it is very clear if you have done something wrong. And it is a bit of an art form with trial and error but the more you know the fewer options you need to try.

That's why lighting design firms get paid so much money because they understand the art of the design and not just the science. There is no substitute for experience.

As a fellow DIALux user your options are -

- Alter the light fitting wattage, reflector, diffuser, etc until you get the right pattern and light level required.

- Consider alternative luminare technologies like LED (watching your light colour of course)

- Look at other offerings from other light suppliers, DIALux-compatable photometric data is commonly available of the supplier websites or if asked for.

- Standards recommendations are recommendations, use common sense and talk with the customer if necessary. Sometimes you cannot get everything to match the standard AND be in budget or match the site construction limitations and so you have to compromise on uniformity or light pattern, this is common practice.

Well in my experience it's always better to have too much light than not enough....that being said I have to agree with what's been said so far that the task of getting uniform light is not an easy task, and almost always involves compromise...This improves with more experience and knowledge of lighting types diffuser types reflector types etc etc...in short like everything else it takes time and effort and a wide knowledge of what's available to work with....which changes all the time....

http://www.dial.de/DIAL/fileadmin/download/dialux/wissen/DIALux_evo-_New_calculation_method.pdf

http://en.wiki.dialux.com/index.php/Calculation_objects

Like some of the other replies, Better a bit too much than not enough.

Is this a warehouse or a workshop?

I am currently working on a hospital project.

Like all things you must be aware of the proper use of software and its limitations. Dialux is a useful tool but the user must be knowledgeable in the subject and interpret results in a meaningful way. Your statement "I do not have a lot of choices to decide which luminaire to use" rings alarm bells, as after 30 years in lighting design I can assure you that there are many thousands of choices and solutions in even the most basic lighting proposal. Here are a few pointers to solve this conundrum:

Luminaires are available in a variety of outputs. Choose the same fitting with lower output lamps or LEDs, or switch to a manufacturer that offers such a range.

Are you applying correct maintenance factors? Include in your estimates the cleaning cycles applicable in your project. Typically Dialux uses an MF of 0.85. Lower MFs will reduce the effective output of your fitting.

What is your perimeter boundary value? Again Dialux typically uses 0.8m from walls but depends on setup. Is this boundary realistic? Wider boundaries reduce the effective floor area for calculation.

Is your area oblong? Dialux calculates the average across an oblong area quite accurately but can go slightly amiss when the floor area is many-sided. (The commercial package AGI does not suffer from this anomaly). This can be resolved in Dialux by inserting separate, independent oblong calculation planes into your project. For example, dedicated over the desk areas. This also gives the opportunity to insert planes at floor level for circulation areas which will improve uniformity calcs.

Dimming solution. Most building regulations (and certainly international standards) require daylight harvesting. This has a secondary effect of dimming fittings to a fixed maximum level in the absence of daylight.

Sorry I could go on and on but this is not a Dialux training course. Suffice to say that you need to be aware of the design methods required to solve problems that software can highlight; only more study and experience can provide this.

Check out this for Electrical Calculations

• UPS Sizing Calculation
• Earth Pit Calculation
• LT Switchgear Sizing
• Lux Level Calculation
• KVAR Calcuation
• Cable Sizing Calculation
• Transformer Fault Calculation