Dear Diva members,

It is required to implement shading / glaring measures when a zone falls out of the max threshold of 500 fc.

How do you model internal shade in Diva for a LEED daylight calculations under version 3.0 of LEED (v2009) requiring that both 9am and 3pm on Sept 21 needs achieve 75% of regularly occupied spaces under daylight level between 10 fc and 500 fc?

Do we need to model the shade (rectangle flat vertical surface offset from the glazing inward) and apply a shading material on it from the .rad material file? Or is there a simpler way to do it?

I am using the Daylight - Grid Based simulation 

Metric: Illuminance / Clear Sky with Sun

Thank you for your feedback

Olivier

Tags: 500, Daylight, IEQ8.1, Internal, LEED, footcandle, glaring, shade, threshold

Views: 333

Attachments:

Reply to This

Replies to This Discussion

Hello Olivier,

As far as I know, in LEED 2009 the letter of the law is as follows:

Demonstrate through computer simulations that 75% or more of all regularly occupied spaces areas achieve
daylight illuminance levels of a minimum of 25 footcandles (fc) and a maximum of 500 fc in a clear sky condition on September 21 at 9 a.m. and 3 p.m. Areas with illuminance levels below or above the range do not comply. However, designs that incorporate view-preserving automated shades for glare control may demonstrate compliance for only the minimum 25 fc illuminance level.

So it seems that if you have some sort of view preserving shade, you do not need to demonstrate the actual effectiveness of the shade, but just presume that 500 fc will not be a problem. I don't work with LEED regularly, so please correct me if I am wrong.

> Do we need to model the shade (rectangle flat vertical surface offset from the glazing inward) and apply a shading material on it from the .rad material file?

If you are modelling a roller shade, this would be the best practice.

Best,

Alstan

Hi Alstan,

Thank you for the prompt feedback and ressources, this is helpful and I understand the same, but this would mean the 10fc minimum level instead of the 25fc due to the addenda which was released in between the parution of the first guideline.

However, as you had mentioned earlier, for best practice, I have been trying to model the shade looking at the following topic: http://diva4rhino.com/forum/topics/glass-custom-material

using the following shading properties:

# Transmission Other Shade
# openess factor: 3%
void trans My_Shade
0
0
7 0.59 0.59 0.59 0 0.02 0.0847 0.6

The shade is an offset of 9" from the window. Both normal facing toward the exterior.

The Glass has clear mat properties.

 

I have attached a screenshot of a close up view. Despite I apply the material to the shade, even a translucent one, the glaring persists and nothing change.

Could you give any guidance on that?

Thanks a lot.

Olivier.

Attachments:

Hi Olivier,

Yes of course the addendum would make that 10 fc, which is comically low.

Anyways, here are some things to check on why your results aren't changing:

  1. If you have a dynamic shading system setup for the climate-based calculations using that layer / translucent material, You need to uncheck 'hide dynamic shading devices' in the DIVA metrics menu, or turn off dynamic shading for the point in time calculation.
  2. Make sure that the layer / shading object is not locked and that it has the material you want assigned to it.
  3. Make sure that the shading material is not part of a block definition in Rhino.

I just want to note that for trans materials the surface normal does not matter, so that should not be the issue.

Best,

Alstan

Hi Alstan,

Great. Regarding your answers:

1- How do you assign the dynamic shading system to the shade layer?

2- The layer isn't locked and has the shade material applied to it.

3- The shade material was part of a block. I have remove it from the block and going to give it a try.

Thank you for your feedback!

Olivier

Hello Olivier,

Sorry for the late reply once again. First, the 'standard' documentation for our shading controls is here. Secondly, we gave a very in depth tutorial on this topic. You can fine the slides here. Finally MIT has a nice video tutorial on the subject too!

With regards to 3, blocked geometries never get exported from DIVA, sadly. You have to explode them first.

Best,

Alstan

Reply to Discussion

RSS

© 2019   Created by jeff niemasz.   Powered by

Badges  |  Report an Issue  |  Terms of Service