Hi there,
For the daylight control point I was wondering by how much the group of lights need to be reduced by, and whether this percentage needs to be of the total wattage or light output? The intent is to control 3 rows away from the facade using a multi-sensor (occupant & daylight sensor in one) at varying reductions (25%, 50%, 75% of full) and then control the internal circulation lights to a lower reduction using a separate daylight sensor. Could the circulation zones be reduced by a minimal amount (e.g. 5% of full)?
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5868 thumbs up
March 22, 2016 - 6:02 pm
I do not think there is a required minimum reduction.
Hard to say anything about the circulation zones without seeing the plans.
Jordan Kirrane
AssociateHurley Palmer Flatt
6 thumbs up
March 23, 2016 - 5:25 am
Marcus, many thanks for your response. The circulation areas are not physically separated to the open place office spaces (the regularly occupied spaces). Therefore playing it safe I would see these as being the one space, and thus requiring some sort of dimming response to daylight.
However as these are are very deep in to the floor plate (10m/33ft) so I don't see the benefit of providing daylight dimming control. Even with high glazing the spaces are too deep for it to be beneficial.
Would you agree?
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5868 thumbs up
March 23, 2016 - 9:56 am
The rule of thumb for an effective daylit zone is 1.5 times window head height. So you would need about 20 foot tall windows to provide any kind of adequate daylight. If on the south side you can augment the depth of penetration to up to 2.5 times window head height with a light shelf.
Again hard to say with seeing it.
Jordan Kirrane
AssociateHurley Palmer Flatt
6 thumbs up
March 23, 2016 - 11:07 am
Marcus, would it be possible to forward on a typical floor to get a better understanding of the implications?
Also the intent of EAc1.2 are for daylight controls where relevant, not to improve the daylighting levels. Therefore if the above rule of thumb holds true the circulation areas that are over this distance from the facade do not need any daylight controls as they will never received enough daylight to warrant this kind of control?
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5868 thumbs up
March 23, 2016 - 11:23 am
I answer questions here because it is in a public forum benefiting many. Sending me drawings crosses the line into my fee for service consulting practice.
I agree that if you have an area too far to receive effective daylighting then installing daylighting controls for that area makes no sense. Unfortunately this may be a case where chasing a LEED point makes no sense either.