Question about ASE study area

Any space that is included in the sDA calculations, regardless if they meet the requirement or not, must also be included in the ASE simulations.

I don;t have the exact reason as to why only the perimeter area is used, bu i assume the reason the perimeter area is used is because of the way hospitals are designed with very large floor plate and many services buried in the middle. If not done this way, i don;t think hospitals could achieve the daylight credit.

Hi Jackie,

I agree with Todd that every occupied space is scored both for ASE and sDA.

The ASE score modulates sDA for each space. For example, if you have high daylight availability (sDA) score of 90%, but too much direct sun (ASE) of 40%, your sDA score goes to 0 for that space.

Please note that LEEDv4 wants to limit ASE (your original text said "more than 10%")

There has been an important recent addendum for ASE:

1. Spaces with an automated dynamic facade system OR under 250 ft squared will now be exempt from ASE.

2. You can now achieve credit for spaces with an ASE score between 10 and 20%, and an extra point for spaces below 10%!

See the full text at:

http://www.usgbc.org/leedaddenda/100002149

Refer to IES Lighting Measurements (LM) 83-12 Approved Method: IES Spatial Daylight Autonomy and and Annual Sunlight Exposure.

This will tell you how to set up your model and what needs to be included and how.

This addenda is super helpful. However the way they define shades, does the same apply for option 2 as well? The reason being, if you have automated shades and then it will come down to prevent glare (above 3,000 lux). It is sort of puzzling as to address the glare issue, there is one requirement for ASE and nothing for the illuminance study option 2. Any thoughts?

I was part of the development and the writing of the LEEDv4 daylight requirements and here is the very brief reasoning behind this without trying to cover months of discussion. Option 1 was developed to move the industry forward by using the most current metric and methods for daylight simulation. Hence sDA and ASE. However, in the many discussions at the time, there where only two simulation programs that could even do sDA, therefore, without knowing when the computer industry would catch up, we decided that option 2 was still needed. Option 2 is the same as v3 requirements with just a little tweek in the method. This would allow projects to still attempt and earn the daylight credit until sDA calcs became the norm and more simulation programs were created to do the calcs.

Thanks Todd for the response. I totally agree with the reasoning behind the adoption of sDA and ASE and with this addenda, the ASE part might become a little easier to comply. The reason being, most high rise spec offices, even they have high performance glazing (such as Solarban 70XL), they dont comply with ASE even with a shallow floor plate. My question is for option 2 and if there are any addenda in the works to address glare in option 2 the way it did in LEED v3 and that if the project has automated blinds/glare control devices, then we just meet with the lower range of 300 lux.

Jude,

Now i understand your question. I know it was discussed in regards to both ASE(as why the daylighting committee developed it) and the automated shades option with option 2. ASE proves you provided a well daylit space without the use of shades, the architecture does the work. An i believe it was the thought that this would also push designers to do the same for option 2. I cannot remember the original writing and not sure if it was included or changed through the many other layers before it was published. But i have not heard nor have i seen a call for an addenda to add this back in. Teams may have to submit project LIs and hope that it may become a version wide LI.

The reality is that floor to ceiling glass floor plates that rise 80 plus floors may have to incorporate things like the Time's building did to meet the credit. V4 pushed everything and the goal is market transformation. So maybe they will not allow the automated shade allowance.