Dear all,
We have a CI project for 3 floors of a existing building. The scope of work includes the lighting and we have a problem with comply with ASHRAE. The Spanish regulations make us have 50 ft in the offices and we dont find the way to satisfy both requirements.
We cannot reduce the LPD because the two options we have one down the power and the other removing the amount of fixtures because these solutions do not meet the Technical Building Code, as the first do not have the required level of illumination (500 lux) and the second we lose consistency. Any suggestion??
Bill Swanson
Sr. Electrical EngineerIntegrated Design Solutions
LEEDuser Expert
734 thumbs up
October 5, 2011 - 1:29 pm
What type of lighting do you have. Lamp type and fixture type?
Incancesent downlights or MR16 track lights are popular with architects and interiors but they will not comply with the energy codes today.
I've also seen linear fluorescent indirects in an office with a wood ceiling. The wood might not look dark but it was absorbing over half of the light.
There's a hundred unknowns about your CI office space so it's difficult to say with certainty "XYZ" is the reason. I had a LEED project where they demanded 70fc on the desktop in an open office. My compromise was I'll provide 35fc ambient lighting and the task lighting would supply the rest. I used basket troffers with T8 lamps. It worked. Just remember to count the task lighting in your power calcs too.
MARIA GARCIA
69 thumbs up
October 6, 2011 - 5:19 am
Hi Bill,
These are the luminaries that we have: Philips TBS260 4xTL5-14W HFP C6 and Philips TBS260 3xTL5-14W HFP C6 and the ceiling is an Armstrong technical ceiling in color white. Unfortunately the Spanish regulation doesnt allow me to use the task lighting to supply the rest of the fc and we have to provide the 50fc with ambient lighting.
Philips made up an study of lighting efficiency and we have 11.85 W/m² instead of the 10.64 W/m² that we need to obtain the Prerequisite. Any suggestion to help us to reduce our W/m² ?? Thanks a lot!!
Bill Swanson
Sr. Electrical EngineerIntegrated Design Solutions
LEEDuser Expert
734 thumbs up
October 6, 2011 - 2:53 pm
If you use the Space-by-Space method you are allowed 1.1 W/sf. That should be 11.84 W/m2.
I did a quick layout with the 4-lamp fixture you listed and I put them in a large room. Ceiling was 10' high. Fixtures were spaced 8' on center apart (with 0.81 LLF). Reflectances were normal 80-50-20. At the work surface I got 52.1 fc with 1.08 W/sf (11.625 W/m2)
Make sure to measure your floor area from the centerline of the interior walls, and outside surface of the exterior walls. It helps. The gross floor area should always be the same regardless of how the walls are laid out.
Bill Swanson
Sr. Electrical EngineerIntegrated Design Solutions
LEEDuser Expert
734 thumbs up
October 6, 2011 - 2:55 pm
Sorry, forgot about the 10% below ASHRAE part of this credit.
Bill Swanson
Sr. Electrical EngineerIntegrated Design Solutions
LEEDuser Expert
734 thumbs up
October 6, 2011 - 3:03 pm
If you were allowed to get the average down to 47 fc you can make this energy requirement with 0.95 W/sf. Tell them this is maintained light levels and that the initial light level will be 50 fc.
You will need some flexibility somewhere. Task lights are preferred. I also played with the floor reflectance and if you bump it up to 30% this will work. But I doubt they'll want a carpet that light because it stains easily. Sorry, I can't help more. Anyone else got ideas.
MARIA GARCIA
69 thumbs up
October 7, 2011 - 10:35 am
Hi Bill,
Thanks a lot for your help. I just had a meeting with the client this morning and agreed on using taks lights to reduce the luminaires of the ceiling so we will reduce the number of luminaires and add task lights on every work station.
Thanks again!!!
Luis Miguel Diazgranados
Green Factory125 thumbs up
October 11, 2011 - 2:45 pm
What about using the performance option? In that case you need to comply with ASHRAE standards but not with 10% below ASHRAE. This is how I understand the credit, but maybe I'm wrong. What do you think Bill?