Proceedings of: Workshop on Improving Building Design for Persons with Low Vision

Introductory comments based on a Recent Article on Daylighting in Architectural Record (2009)

The subject matter for our panel is natural lighting. I’m not an expert – I am an architect – but I did do a little reading. There was an interesting article in the Architectural Record in 2009 on daylighting. It was weighted toward energy conservation, energy savings, but also there are a lot of issues in that daylighting article that I think are very pertinent to our topics for the workshop.

I want to make a couple of quotes from it and then sort of go through some of the things that the article brings out, because I think I can do that very quickly if it kind of piques your interest, and point out some of the things that architects [try to] mitigate – problems for [design solutions].

And first of all I would say that none of us can do without sunlight. Sunlight is an essential part of human life. You know, doctors recommend at least 10 minutes of exposure to natural sunlight a day so that you can produce enough Vitamin D in your body to keep your bones strong.

So we’re not hermits. We don’t live in caves. We do have to expose ourselves to some sun. The question is, how do we control it an indoor environment so that it doesn’t become [ a hindrance] in what we do, especially if we’re sitting in front of computer screens in federal agencies or private sector offices, whatever [we do in buildings] today.

(Tom will provide copy of article or a complete reference to it.)

Two interesting quotations at beginning of the article: 

The article has an interesting quote at the beginning of the article that I wanted to share. “A central challenge of effective daylighting design is allowing natural light to penetrate deep into the interior spaces while eliminating glare and heat gain or loss.”

“One of the most common failures today in daylighting strategies is glare control. Large window areas provide generous amounts of daylight to task areas, but if daylight is not properly regulated, glare results, particularly in today’s computer environment.”

Solar Gain and Glare are Major Issues for Energy Control

So that’s a big issue, solar gain and glare. For those of you that are dealing with energy control in buildings, that’s a major issue. It’s a major issue in our federal buildings, which have large glass exposures and often because of design policies that were originated with Design Excellence – enormous glass atriums, which are, in and of themselves, very problematic for energy mandates now coming out of the White House and so forth.

Architectural Control Techniques for Daylighting

So what are the techniques that are used to control daylighting that architects can take advantage of? Well, this whole myriad of starting with the exterior of the building wall. There are various things now that automate louver systems that have controllers – computeroperated controllers that are geared to the action of the sun, prevailing cloud cover, et cetera, and how the louver systems on the exterior of a building will control the daylight entering it.

This also can apply to interior blind systems. There actually are automated blind systems that have been developed that allow blinds to raise and lower and to adjust the angle of the louvers in the blinds so that they can compensate for the angle of the sun coming into a building, and reduce glare. So the blinds can be lowered so that you don’t get glare into a work area at the times of day when the sun is penetrating, and raise it at other times of the day.

Building Orientation and Areas of Glazing

Of course, we all know the basics of architectural design is your north and south exposures of a building are the ones that are least – that are most uniform in terms of light. They’re the ones that are the easiest to control. It’s those east and west orientations where we tend to get the most glare penetration into a building because of the severe angles of sun -- sunlight, sunset, time of day, et cetera, to deal with.

Exterior Louvers and Light Shelves

So starting with the exterior, there are louver systems. There are what are called light shelves, which are horizontal elements that can be built into the building façade that will bounce light to the ceiling on the interior space and allow it to penetrate deeply into the space and reflect light downward into space, but will not allow it to penetrate directly into the space.

Those are good in certain environments, not all environments. What you would do in Texas or Arizona would not be the same thing you would do if you were living in New England or in the South or in the Pacific Northwest. There are all kinds of variables.

Then we go from those systems, which can be eliminated and sometimes are. Some of our GSA buildings have automated systems of this type and use light shelves and some of these elements.

Glazing Systems

The next line of defense is the glazing system. And shading can occur both inside and outside. So you have a choice of different kinds of shading. Some light shades are actually built in the envelope. If you have a double-glazing system, they’re actually located in the envelope inside the two layers of glass – can be automated, can produce great energy savings as well as providing the shade for the light, controlling the glare.

The probably least effective and most commonly used exterior controls on windows, which are louver systems of all kinds and whatever, you get solar gain though glass that way. You don’t control that, so your heat load inside the space is going to tend to be the highest level of heat load because you’re controlling it from the inside rather than from the outside.

On the exterior of the glass, the glazing systems, there are several ways of dealing with that. Glass today can have a tint built into it. It can receive various kinds of coatings. There are double-glazing systems, triple-glazing systems. It can have interior coatings as well. Some of the most recent coatings are very, very effective at reducing solar energy in interior spaces as well as controlling the level of light that you get.

Interior Blind Systems

[Automated blind systems have been developed that allow blinds to raise and lower and to adjust the angle of the louvers in the blinds so that they can compensate for the angle of the sun coming into a building, and reduce glare.] [Editor’s note: this statement was previously made by Tom, and added here for consistency]

Energy Implications

So, there are a lot of different techniques that can be used in designing buildings to control sunlight that comes in and achieve some of the results that we need to control solar glare for those with low vision. That’s kind of an area of design that is a specialty area. There are many, many companies that specialize in one component or the other of this. It’s the architect’s job to look at the whole global picture of what’s available on a palette, on a design palette, to deal with all of these issues of sunlight control in the building space.

And I don’t want to say a lot more than that. The article is very interesting and the record is – it has a lot of different solutions that have been developed. Some issues about glass I didn’t know. There’s this new kind of coated glass called sputter-coated glass, which actually uses a thin layer of silver that can be applied to the glass. This is one of the best, probably the most recent light coating out there. It really has a huge ability to control solar gain.

And that plays into all the issues about energy mandates and controlling how much heat [transfer that occurs] in the building, et cetera, and heat loss as well because these reflectivity possibilities with glass can apply either to preventing sun from coming in and heat gain, or they can also work the opposite to keep you from losing heat in cold environments. So there are just multiple issues out there and many, many ways of handing it.

I’ve said enough. The panel here today is comprised of folks you’ve already – I think with the exception of Mark. Mark, were you on a panel –