Hello:
My team and I are unsure whether our project site should be considered LZ1 or LZ2. The project is located in a public zoo campus setting, within a much larger public park area. The Zoo itself is modern, well-developed and maintained, and heavily themed with extensive commercial operations (gift shops, food and drink kiosks, etc). There is a mixture of existing luminaires, many of which are not full cut-off. The luminaire we have selected will be located under a canopy, but does produce about 2% uplight lumens. As I read the MLO, LZ2 is an appropriate choice for us...but I'd love some feedback.
Thanks-
Bill Swanson
Sr. Electrical EngineerIntegrated Design Solutions
LEEDuser Expert
731 thumbs up
June 4, 2018 - 3:47 pm
The lighting zones are not well defined.
http://darksky.org/lighting/model-lighting-laws-policy/recommended-light...
LZ0 - total darkness.
LZ1 - low light levels.
LZ2 - moderate light levels.
LZ3 - moderately high light levels.
LZ4 - high light levels.
The MLO user guide has some text for examples of uses in each lighting zone.
LZ-1 - "May also include the developed areas in parks and other natural settings."
LZ-2 - "... business areas with evening activities... Can be used to accommodate a district of outdoor sales or industry in an area otherwise zoned LZ-1."
I can see this area being either LZ1 or LZ2. It is the design teams choice which LZ to pick, just have an argument ready to defend the location selected.
My preference would be to minimize the rating of fixtures near the animal enclosures to LZ1. If you want LZ2 around the commercial operations that is fine.
Carl Karlen
June 4, 2018 - 6:31 pm
Thanks very much for your input...
Niraj Poudel
Sustainable Design SpecialistHOK
July 25, 2018 - 4:00 pm
How about the fact that the luminaire is under a canopy? My understanding was that luminary under an overhang or canopy are exempt from the calculations?
Bill Swanson
Sr. Electrical EngineerIntegrated Design Solutions
LEEDuser Expert
731 thumbs up
July 26, 2018 - 4:06 pm
I wouldn't say exempt. You need to show that 100% of uplight from a light fixture is blocked by structure. Does the canopy or overhand block 100% of the uplight? Most don't.
Some canopies are made of plastic or fabric that allow some light to pass thru. You need to say what % passes thru.
Most of the time the uplight is mounted below the edge of the canopy. This makes an angle between horizontal and the edge of the canopy that allows some of the light to escape up into the sky. Most of the light will be shielded, but you need to show how much light escapes upwards. It depends on the light and on where it is mounted. Maybe it's only 5% of the light. But it still has to be included.
Niraj Poudel
Sustainable Design SpecialistHOK
July 26, 2018 - 4:27 pm
Thank you Bill. I appreciate your expert response!