Workshop talks given at Southern California Edison

Kerry Hegedus

Kerry Hegedus is an architect and has been working with Naramore, Bain, Brady and Johanson (NBBJ) Architects in Seattle, Washington since 1991. Projects include the Seattle Justice Center, Arizona Solar Oasis and the Safeco Field for the Seattle Mariners. Mr. Hegedus has a bachelor’s of architecture at the University of Arizona and a masters of architecture and urban design from Washington University in St. Louis. 

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[2] It turns out that the topic that the Lawrence Berkeley National Lab was interested in is how we “convinced the client” since this particular building I will talk about uses a double-skin façade for a thermal buffer and they are pretty rare in the US. The building is the Seattle Justice Center. The owner is the City of Seattle. Two uses are programmed in it: City of Seattle Police Headquarters and City of Seattle Municipal Courts. It is about 12 stories tall and about 4 months from completion. It is located on a half-block site in downtown Seattle.

[3] I broke it down to three basic criteria. First of all, it had to be aligned with the client’s goals. We didn’t come up with any premeditated idea and try to force it down their throats – it kind of grew out of what the client’s goals were. Second, the thermal buffer is integrated into the building concept on multiple layers. We wanted to make it substantial and a part of the building, so that you couldn’t just snap off or replace or value-engineer it out. Third is the research and development to confirm the benefits that we told the client we were going to obtain and to better fine-tune what that thermal buffer was going to be. The picture shows a façade model of the typical bay going up the whole nine stories.

[4] Some of the favorable factors that helped us convince the city were in place even before we started design. Our mayor, former mayor, Paul Schell, was formerly the dean of architecture at the University of Washington. One of our clients was an architect, which also helped. In terms of design and aesthetics, Seattle has a pretty rich heritage of being concerned about these ideas even though some of the buildings of the past do not necessarily reflect that. The city architect was an advocate of sustainable design and this was probably one of the key features, that they wanted to have a sustainable building but they didn’t have the budget. That is why this is a reality check. This is something that we did with relatively little money with a client that really wanted to push themselves. Some of the more physical characteristics was the site orientation and the location on the master plan. These were developed before we started design. The clients had similar goals of where the building should go as well as image and a LEED rating. The city acted pretty quickly to adopt the LEED ratings that came out at the beginning of 1999 and by November of that same year, the city had adopted it and said that they wanted all their future buildings to have a silver rating or better. So they were pretty aggressive. At the time, I am not sure that anyone knew what that meant. When we were first analyzing it, there was LEED version 1.0 and then they adopted version 2.0. Then something else that helped was the Berlin coincidence that I will get into in a little bit.

[5] The biggest thing was the LEED rating system and how were we going to accomplish the silver rating. Along with the LEED rating, they just didn’t want to hide the sustainable features in the building, they wanted to create an awareness to the environment and to the public. They see a double curtainwall and people can start asking questions. They can start telling a story of the building and build some momentum. Then with the next project, they will try to do something more advanced and more integrated. The city also wanted to show sustainable design as an example of just good practice. They just didn’t want to do things, the city wanted to show things that were the right things to do, and they wanted to lead by example. From the image side, they wanted something that was inviting. Right now the buildings are not very attractive. People dread going there. Of course, the building houses the police and the courts so you usually go there for negative reasons. They are not good places to work in, they are not good places to visit, and there is just no real strong attributes to them. So they want something that invites people back into the government and they didn’t want such a stand-off type of environment. In terms of convincing the client, the glazing thermal buffer or thermal flue is a new concept. At first we had to worry about the fashion questions. Were we just trying to put two layers on here because it is trendy, or is it really going to have some benefit? So we went through a series of copying the client on book excerpts and articles. We wrote a short explanation of what our thermal buffer was, what precedent there was, and how the concept worked.

[6] Then to top it off, we had a sister-city relationship with Berlin. This was really fortunate because the clients were going there and they said, “While we are there, can we look at any buildings?” Yes! That might show you what a thermal buffer looks like. So there was some real good extreme examples of thermal buffers and how it integrates in the building. I gave them a map and showed them how to get there. I really wanted them to be excited about it and it was the architect from the city council and the mayor. They were anxious to go look at it. They wanted to know about this thing called a thermal buffer. So I listed the buildings, they walked around and came back, and they were as excited as I was to sell it to them. But it was not about salesmanship. It was about creating the right thing for the building and I will get into some of those circumstances.

[7] There four considerations: 1) Location on the master plan, 2) building massing, 3) space planning/room layout, and 4) solar orientation. It is these many layers of consideration that made it important for integration into the building, something that you could not argue one point and the whole thing goes away. That is the real test of anything that you do in a building; if there is only one reason to put it there and it isn’t functional, it will more than likely go away.

[8] The master plan. Our building is composed of two squares there to the right of the screen. It is really the first phase of the city campus. The city hall is across the street with the council chambers (it has a circle with a square through it) and this really became the back drop for the city council, which is more of an object building being designed by Bohlin Cywinski Jackson and Bassetti in Seattle. You can see that the master plan stopped at the city hall and then there were just these two blocks at the east end. And looking at what the master plan is, it creates this urban corridor to the north where the mass of the buildings are and then the parks and open space are on the south side, where it can get sun and get some public access. So how did it fit in the master plan? We are at the high part of the hill, in the far right. You can see kind of a current photo of how we fit in there.

[9] The Seattle Justice Center mass was broken down into two elements. The police became the stone portion: the solid sturdy, you couldn’t bomb that part (or you couldn’t think that you could bomb that part), and then there is the court side which had more of the public outreach items, where people went everyday for jury, to pay parking tickets, or utility bills. The city really wanted the courts to be more open to the public. That is why you see the separation of the stone mass and the glass. Also you can see where that would be an extension of the master plan – it really sets this one area off to be glazed and be different and to be the back drop for the city hall across the street.

[10] In terms of the planning layout, first this is facing southwest and so it is not the best of orientations. Considering the half-block configuration, this is what we had to deal with. We had a parking garage on the back side and we had two short ends that really were not going to be of any use for daylighting due to the depth of the block. So we really had to concentrate on the southwest elevation and how we could make that work. With glass, there is always those extremes of temperature variation and glare. What we ended up doing was pushing back the workstations and putting circulation right behind the glass layers. This made it so that people at the glass line did not control what everyone else in the whole space experienced. That was a big factor. Also in terms of the image. You don’t have to worry about the desk being shoved up against the glass and people adjusting the blinds at all different levels. We wanted the façade to be really clean. We were very systematic and rigorous on this southwest side where the thermal buffer was. In terms of the bays and where the private offices were placed, we had “cabin creep” – we said that if you were going to creep your cabins into our open office space, they were going to be at the back so that daylight will at least have the opportunity to penetrate back into the space. We knew that everyone was not going to get direct daylight but we wanted them to have access to direct daylight. Again, we were just trying to deal with the circumstances that we had. On the police half, anything can happen. We tried to keep open office areas against the main core, but because of program variations and a lot of private offices, it just broke down systematically.

[11] The solar orientation. I hit on it that the southwest was our major elevation. If you have ever been to Seattle, it is a very beautiful place and people are very connected with their environment. Especially beyond the highest point of the hill, we wanted to give access to the views to the water and to the mountains beyond on a clear day. It is very important to feel in touch with our community out there and conversely, for it to be inviting. We wanted to have clear glazing so that you could see in. We wanted to try to maximize the glazing so that you could start to wonder what was going on in there, that it is not so forbidding. It is not tinted glass; it is not reflective. We just wanted to give something that the public would want to go in and experience.

[12] The research and development. To confirm these benefits, we did this analysis at schematic design. We were toying with the thermal buffer idea. The city hired Arup to come in and just go through all the city projects at the time to see if their sustainable strategies really held water. At which time we had Maurya McClintock from Arup come in. She went through our strategies and confirmed our strategy. We ended up hiring Arup to help us analyze thermal comfort and energy items with the building and to help fine-tune how to best make our thermal buffer work.

[13] We studied this thing in a lot of different ways. First we were testing just sun angles both in plan and section. How do you get the daylight to penetrate? Very typical things, but the start of the investigation.

[14] The modeling at different scales and at the different phases, different emphasis (like the façade). The one in the lower right hand corner is the daylighting model. We took it to the daylighting lab and made modifications, looked at sun angles at different times of the day, did stills, and tried to get an understanding of how this would work.

[15,16] There were computer simulations. This one was done relatively early as well to gain our understanding. These are probably about as far as we normally would have gone if we weren’t trying to integrate the thermal buffer and really maximize the glazing. We knew that there were going to be more pressures to make this elevation perform. The Seattle Daylighting Lab really helped identify a lot of critical issues and there was a really big problem. Especially for the southwest orientation. We went through shading strategies, where the light shelf was, how far the blinds went down in the thermal buffer.

[17] What we have in the thermal buffer is monolithic glazing on the outside and insulated glass on the inside. In the gap, we have cat walks at the floor levels. These light shelves were initially eight feet above the finished floor. Then at first, we thought that we were going to have frit the upper portion to get some of the glare issues out, but we concluded through the analysis that what they really needed was a MechoShade. The MechoShades (semi-transparent shading) come down to 6 feet above the finish floor and balances against the city standard for partitions and cubicle heights, which is 5.5 ft high. Then we had the catwalk at the floor level and the light shelf at 8 feet above finish floor. All of these things kind of balance. It is a fine line of how much sun you are keeping out; for the critical times and swing times of the year, it worked. Through all these things, again, we didn’t have a big budget. The analysis was relatively simple but multi-faceted. We had to make sure that it would work with what we had. Ove Arup really helped convince the client too. We had never done a vented façade before. We had been talking to a local engineer that had done some, but didn’t have the bulk of the experience that Ove Arup had, so that really helped add some confidence from the owner’s standpoint. This is one of the reasons why we hired Ove Arup, because they could do an extensive study and they have done 70 plus thermal buffers that have been built.

[18] In terms of value engineering, we were trying to see how far we could minimize it (thermal buffer). We didn’t want any moving parts, because the city would not maintain it. Could it be whittled down to single glazing on the inside and was that going to be effective? We looked at different options and we also compared it to a traditional configuration. I am not sure why Arup does this, but they calibrate things. These colors are for the percent of people dissatisfied. It seems to be a pretty negative way to go about it, but their philosophy is that they are going to always have about 10 percent of the people that are dissatisfied, no matter what is going on. That is always the goal, and that is the yellow here. You can see up against the glass on the far left, circulation zone, where we’re not going to let people occupy the space.

[19] Further break down. In the end, you will notice on the third line down the energy analysis for the area studied, which was only 18 ft deep on the southwest side and on only two-thirds of the block. The thermal buffer equated to a 33% savings in terms of energy. In terms of the overall building, it calibrates way down to about 3%, but because it was a limited location it couldn’t have that wide-spread effect. It was a lot of these little things that helped the building perform better.

[20] We had to work with the contractor. There was some scare factor in terms of seeing a double-wall façade. They wanted to do it the way they had done it before. We experimented with a process, a “design-build process.” From our DD documents, we advertised and got two contractors (really subcontractors, because we had GCCM onboard at that time) that would develop their own designs. While we were doing constructions documents, they (Benson Industries) were doing their construction documents. We were working with them to develop two designs to meet our criteria. In doing so, we were allowing them innovation. They had the budget that helped allow for some additional innovation in the end. It is the first time that we tried that and it was a lot of work, but I think that there is some potential in that process. Early this morning at the SCE Round Table, we talked about the problem that by the time that you complete your construction documents there is not enough time to do a mock-up or change things with the contractor’s feedback. This might be a way to start to get around some of those items.

[21] In the end, the only way that we knew that we were going to make this happen was to keep it simple. Use simple technology. We did not want to have to develop a lot of things, make custom extrusions, do a lot of wind tunnel testing. We started with integrating a lot of building concepts on sustainability and in the end, it kind of came down to just one that we tried to layer and tried to make work for our circumstances.

 [22] I guess we won’t know whether it is successful until it opens and if they are really comfortable and the people do connect to the building. But for now, all I have to hang my hat on is that the city council member, when he came back, gave me his message that he was sold and I feel that the clients were convinced. All we have to do now is convince the occupants.

Question/Information: eslee@lbl.gov