glare control devices on skylights?

In a word, Yes. In many words...The prescriptive options designates the amount of diffusion the skylights must have. This diffusion indirectly controls glare. The simulation and measurement options restrict the amount of light allowed onto the measurement plane. This also indirectly mandates glare control. Beyond meeting LEED requirements, it is recommended that clear skylights or clear roof glazing of any sort should only be used in areas where direct glare can be tolerated, for example, transition or break room spaces.

The Reference Guide only states every window, so is a skylight a window? As regards to LEED i have yet to read anywhere where skylights were required to have a glare control device. Typically, a skylight would not be in ones cones of vision, and as long as they were diffuse, can you label it a window. If they were north facing and or clear i would ensure that there was no potential for direct solar or glare.

In the spreadsheet, they said the glare is optional if the simulation shows illuminance within the range. I am not sure whether I have the latest spreadsheet. Outside of LEED, i think it is necessary to provide glare control if the direct sun from the skylight falls on task area. However, if it is diffuse material and doesn't cause high contrast, I don't think it is necessary.

Eddy, the spreadsheet does state that, but it is in contradictory to the Reference Guide. I have not yet got any clarification to this issue that has been around for awhile. Here is the other dilemma, would a space need glare control if it one of it walls were say of Kalwall?

Todd, In my personal opinion, Kalwall should qualify without blind. It has diffuse property and it won't cause any high contrast. The material of blind sometimes has even higher VLT than Kalwall. I think it will be similar case with solatube. I don't think both kalwall and solatube needs glare control. I saw this provision : Provide glare control devices to avoid high-contrast situations that could impede visual tasks. The worst case scenario is that we need to provide glare study to the reviewer as a back up information.

Eddy, I agree that Kalwall doesn;t need glare control devices, nor would solar tubes at this point in LEED. Depending on the haze factor, location, orientation, and activity of the space, there may be a time where something may be needed. I believe a glare/contrast study would work if questioned, but what would you include in the study to the reviewer? I believe many reviewers may not even be able to readily define glare or what entails in a good glare/contrast study. Well I'm about to find out real soon if these items will be questioned or not. We have a project that has north facing skylights that are clear, south facing skylights that are translucent, and Kalwall on the east and west facades. Sims show good daylighting, contrast ratios are within 1:4 in the worst case scenarios, and blinds are used consistently. Daylighting design was based on Daylight Autonomy and not LEED requirements, but it easily meets the LEED requirements for this version.

I included a luminance study, but I agree with you if they may not even look at that. The daylight review is not as detail as EAc1 review. I never received technical question from the reviewer in daylight. They mostly asked about the regularly occupied, etc. I bet your project should be OK. 1:4 luminance contrast is very good. If you don't mind sharing after receiving the reviewer comment, it will be great. The reference even includes fritted glass as their glare strategy. In most cases, I believe the fritted will create more glare than the diffuse glass.