Glare Control Type Question

No, a glare control device must be able to be manually operated by the occupants or automatically controlled. If you have implemented exterior shading or other architectural elements to help control glare and provide good daylighting, i would suggest that you use the simulation option.

I disagree. I don't see any reason why you can't used fixed features for glare control. However, these features must shield the window from all direct glare for all occupied hours. Technically, even an extremely low Tvis (usually accomplished with window obscuration) could block glare altogether.

I have had some long discussions about what is considered glare and glare control devices. I agree that overhangs or exterior shading devices can control some forms of glare, but in regards to someone using the prescriptive method, which is not orientation or climate based, how can it be proven that said devices do what it does. It can't. Therefore, with the prescriptive method, and even the other options, glare control devices are basically manual or automatic shades. The other reason GBCI consider shading devices shades is that many project probably do not take into account the effects of reflections, such as off facades of neighboring buildings and even windshields off cars in the parking lots. So a building may have exterior sun shades designed based on the sun path, but what do the occupants do when the sun is reflecting off a neighboring building or even off snow and they can;t block it?

I haven;t bought into the whole extreme low VLT solution to solve issues like these. The relation of the quality of view and the spectrum of light that the eye receives is very much connected to ones circadian rhythms and health. I will have to look for the study that i read awhile ago about the effects of the quantity of light that young adults are exposed to and its effects upon sleep. There is a part of the light spectrum which effects this. So if you were to use an extremely low VLT or obscure the view, this spectrum could be removed.

I'm a firm believer in providing as clear of glass and highest VLT possible. Make the inside as connected to the exterior as possible.

I didn't see "prescriptive option" listed in the question. True, you should not be using the prescriptive option if you are using fixed glare control.

Daylighting for quality and daylighting for LEED are two different discussions as much as you and I would like that it wasn't. I agree for quality daylighting that visual spectrum should be preserved as much as possible, but there are quality low VLT glazings that will do this. Personally, I would not recommend this for a majority of windows in a buliding, but if you can't locate blinds on, for example, a window in an overhead door, a low VLT could be an option and an energy-efficient one.

Applying a "highest VLT as possible" policy in all situations ignores the complexity of the human visual system especially in different space types and reduces options for energy-efficient glazing.

Having a view is addressed in the Views credit. An option such as low VLT glazing should not be eliminated in the daylighting credit when daylighting for LEED, especially if the views credit is not being attempted.

Gabriel G has been the one asking all about the prescriptive path, therefore the response was towards that option.

I agree on areas such as doors and other areas like that where harvesting views and daylight through is not critical, one needs to look more at the thermal performance. ie, glass stair towers.

To clarify, i wouldn;t recommend a VLT of 70% on a glass box in Dallas and also recommend that they not install blinds. But if by some chance they wanted a glass box and no blinds, then yes, i would say to balance the energy side and the daylighting side, that you have to go dark. But there are now some really good high VLT low U value and SHGC glazings on the market.

Yes in LEED the views and daylight are separated, and if you design a to scorecard, well then you;ll look at them as separate elements and not as a whole as they should be. You can use a low VLT if you want but i won;t say that a certain level of VLT takes the place of a glare control device. By glare control device, i mean one that has the ability for all types of glare. I also think that there is a certain level of VLT where the view is not what is considered a quality view (the discussion of quality is a long one and has many opinions) I look at this way, the view you get wearing sunglasses is not the same you get without them. Same with the amount and quality of daylight.