No Thermal Break, No Problem: Upgrading Kahn’s Stainless Steel Windows in the Richards Building

David N. Fixler: I’m going to venture out
on a limb for just a second because James’ presentation recalled something to me, very
poignant and very personal about something that happened a long time ago. Loretta Venturelli
who is an architect in New York in the late 1970s, and worked with Donald Judd on some
of this work, and I only know it because she taught me in so many ways how to draw, and
so much of what she was teaching us were the kinds of wonderful drawing she was doing on
these buildings in Maurfa. I can speak nothing to her involvement of the technical details,
but it is, in terms of the power and quality of those buildings, always has resonated with
me, and it was great to hear James talk about it in that way. On to Louis Kahn, the Richards
Laboratories, first of all, I want to thank the park service and NCPTT and World Monuments
Fund, all of you, for inviting us here today. We are honored and thrilled, and I think that
they’ve given everything we’ve heard the last couple of days. I think there’ll be some interesting
material to add to the archive here. The Richards Lab, as many of you know, was
a notorious building before it was even finished. Vincent Scully at the time, it was being designed
by Kahn said it clearly, came right out and said, “This is a landmark working 20th century
architecture. This is changing architecture.” The buildup was such that, before the building
even opened, it had a solo show at the Museum of Modern Arts, so this is a very, very important
building. It’s a building about the integration of structure and systems, and the whole notion
of servant and serve spaces, which Kahn became so famous for, really came to the fore for
the first time in this building, but what’s poignant about it is you see this quote here. What this is all about is, of course, he really
thought of laboratories as being like architectural studios. People would want to work in this
big, open, light-filled environments. Unfortunately the nature of the programming process, whatever
he went through with the University of Pennsylvania in the later 1950s, he didn’t really get to
talk enough to the scientists who were going to be using these labs and consequently from
the day it opened, besides being internationally famous as upgrade architecture, it was famously
dysfunctional. To the point where the University of Pennsylvania, the people who used this
building, were threatening to just leave or blow it up or do anything. But I say that,
not so much to criticize the building, but to say to instill in you the need that we
had to change things. This is an instance where it is a national
historic building, it is an iconic building, there are certain things you absolutely can’t
change, but there was much, specially problematically on the inside, that had to change for the
building to survive. Looking at Richards, basically the original
Richards is the four buildings that the four blocks that have the letters in them. The
blocks to the right are the Goddard Labs, which were designed also by Kahn, but build
subsequently, and under a little bit of a cloud, so a lot of the detailing that was
realized there doesn’t come up to what you have in Richards, but it’s the idea of the
servant. This is the servant, and these are the serves, so you basically have an essentially
the brick box here, and these highly glazed tower surrounding it. Here’s the building under construction. Kahn
was very heavily influenced in the design of the structure of this by August Komendant.
This was first collaboration with August Komendant, as a sort of visionary structural engineer
who worked for 18 years with Louis Kahn, and wrote a very sort of tell-all book about it
some years ago. Here you see the building going up, and the idea of the very strong
expression of this reinforced concrete structure with these precast Vierendeel trusses, which
cantilever off the columns that really formed the centers of each of the served bays. The purpose of that was to open it up to the
world at large, but also in Kahn’s notion of creating community, being able to see into
each other’s lab, to be able to have this communication that is evident in this wonderful
photo by Mildred Schmertz, shortly after the building opened. The idea that these enormous
windows allow light and quality to permeate from one side to the other. Here you see the
actual plan. The thing that’s important to remember, which we’re not going to go into
in this presentation, but is certainly a very important part of the story, is that interior
partition layouts within the glazed towers really were of no consequence to Kahn himself. As I said, his preference was to keep them
all open. However, they did conform to his system which aligned where the partitions
really could be used on a line with the structural grid, and here is a reflected structural plan
of a typical floor. You see these four squares within the nine squares of each of the corners.
One of the things that we had to face was dealing with the fact that if you follow those
lines, they don’t meet office standards, and I say, that’s a presentation for another time,
but it was a very interesting challenge as to how we dealt with that in coming up with
new schemes for the interiors of the building. Here finally for this introductory piece is
the tinker toy pieces in construction going together, and you can see the extent of the
cantilevers that you have here, and part of that the movement because of the concrete
creeping those cantilevers and the expansion of the brick were some of the things that
we had to deal with in facing the changes to the glazing later on. Matt? Matthew Chalifoux: Thanks, David. Coming through.
As David said, there were functional problems from day one, but this another one of these
pre almost construction finish photos, certainly gives a sense of what Kahn thought the spaces
should look like on the interior. This is actually looking into Tower D from Tower C,
so from the servant to the served towers. You can also see in this image, in the Vierendeel
truss system above, the organization of some of the mechanical systems that fed the building,
which is what I’m going talk a little about because it was also very important to the
vision of the building. This is what we are faced with going into the building, so this
is how the building has been used pretty much since it opened up. You could see the kind
of overlay of systems and things that have been put in and the kind of degradation of
the space based on how it was being used. As David said, this incredibly important planarity
of the exterior envelope, and the way the materials met each other, which has been partially
compromised based on minor movements particularly around the corners of the buildings as it
relates to the windows. A critical decision that the university made prior to our evening
engagement was the decision to change from wet labs to cognitive neuroscience in this
building, which was going to take a lot of the kind of systems on pressure on the building,
and allow us a lot of freedom in terms of how we’re going to be designing the building
and designing the systems. Our scope we’re working include initial feasibility study
and then renovation of just two floors of two of the towers. It was a limited scope,
although they’ve now moved into a full renovation of the entire building. Penn was not prescriptive about the solutions
that they wanted. They did provide a sense of their expectations. Just from the RFP,
they stressed that they expected the high sensitivity and coordination between historic
preservation, mechanical engineering, and space planning. The design should result in
a high performance, energy-frugal, light-filled, and healthy building. I stress that word “frugal”
because it gave us a sense that Penn, which is very aggressive in their energy reduction
targets for their buildings, both new and existing on the campus, saw this as a potentially
different project. They were not mandating specific reductions, but they were asking
us to be energy-frugal which was a nice way to start the project. I just want to mention that David and I were
backed up by an incredible team of people and firms. One of which I want to point you
specifically, on the envelope windows are [inaudible 00:08:29] Associates out of New
York, Loretta Polinsky and Aaron Davis. Much of what they produce is critical to the presentation
you’re seeing today. All of these people had to buy into the kind of design approach that
we are developing even though the systems and everything are maybe typically thought
of as independent. The final partner I want to mention is the construction manager, Intech,
because many of the end solutions that were developed were only developed with the input
of the contractor and the subcontractor to make sure that they would work. One of the things that we wanted the feasibility
study was to really be able to guide us in terms of how we were going to be dealing with
the building. We had to think about some basic design principles that Kahn and his team have
developed in developing the design. One of which was how all the materials in the building,
the junctions between them, how they meet each other, and how they terminate, and these
are snippets from some of the original construction drawings. This happens to show two cinder
block walls would meet, but also a typical door head window where you really only have
jams, and you have no head to the window. It really simplifies the lines of the building,
and it was something that we had to always keep in mind. On the mechanical systems, what was really
critical in terms of the mechanical systems is that they were treated as a visual element
in the building. Kahn stressed the idea that the architect should understand everything
about the structure, and the systems and the construction technology because it all had
to be integrated into a whole. It was not thought of as separate components. The layering
and mechanical systems that’s sectioned, it’s at the bottom of the screen, shows how the
systems were layered in the Vierendeel trusses were to highly organize them visually, but
also to allow the systems to feed up to the floor above for electrical and telephone,
and then for the mechanical systems to feed the level below, which meant that you had
no systems that had to go through the zone that’s created horizontally by the windows.
It’s a very, very important issue. This diagram was from Tom Leslie’s book, “Louie
Kahn Building Art Building Science” and it shows just the rigor of the layout of the
systems, and how it was worked into the Vierendeel trusses, which again was something that we
had to pay close attention to because we were going to be changing the building systems,
but we had to think about what that meant in terms of these designs. A quick diagram, one of the key things that
the university also wanted to explore was the idea of changing from their standard design
HVAC VAV systems and go to chilled beams systems. The benefit of this was both energy savings,
but also further reduce the size of some of the duct work and the routing that we’re going
to have to deal with, simplified some of the coordination issues for us. We also had offshoot
benefits specifically as it related to the window design. It also posed us with the problem
though of we’re going to have new objects in the space, and what were they going to
look like. Chilled beams, there’s not a lot of range of them available in the market,
so again thinking about how they are going to lay out in the building. We did all of
the layout design of the systems in rivet. We used it as a design tool. We actually would
use it in design meetings with the owner to understand exactly visually how this was going
to look in the building. David N. Fixler: Now we’re into the windows,
this is a construction photo, and I think it shows a late construction photo. It is
before they start to put in any of the interior partitions, and it emphasizes the vitrine-like
quality of these windows, and the incredible Christmas [planarity 00:12:08] of the system
that Kahn was able to develop. I’ve been doing a lot of research on this system, and it is
quite ingenious. This is where the no-thermal break no-problem comes in because it does
not have a thermal break, but it is an incredibly elegant system. Given all of the chatter that
was happening in the 1950s and 60s about making very, very minimalist curtain walls, nobody
really talks about just how well a job, how a good job Kahn did in achieving precisely
that. The building on the left is the AFL Medical Services Building that he did in Philadelphia,
which was unfortunately torn down in the 1970s. But this is where he first began to develop
this, basically it is a matte finish, break metal, stainless steel folded plate system
that he uses to create these windows. There on the right, you can see a view down the
window. I also want you to take note, if you look
really, really carefully, you can see a little bit how the brick wall comes out and the corner comes in, and that kind of deformation in geometry was one of the
really tricky parts that we had to deal with all along.
These are details of the, very quickly going to go through the evolution of Kahn’s thinking
about windows, these are steel windows in the first proposal for the AFL Medical Building.
Similar to actually the steel windows, he did at the Art Gallery, which was of course,
some of the building that he had finished right before then, but as he’s working through
the design, he also proposes an aluminum alternate, and then finally goes forward with a folded
plate, break metal, stainless steel system. Here are the design drawings, and then here
are detailed drawings from the actual construction and submittals that went through in the construction.
He’s thinking very hard about this, and working on this idea of creating this incredibly sheer
surface because there are no tubes. The sections are very, very light, and they get all their
strength from just being folded. Here now is a detail sheet from the Richards
Laboratory. You see, first of all, the size of these lights, they’re almost 14 feet by
5 and a half, the big ones, and they were just quarter-inch polished plate. The dark
sections that you see in the upper right hand corner are the actual profiles, a jam at the
top, and the sill at the bottom of this. You could see how incredibly minimal that is,
and very, very little. The only projection really from the surface is where they had
tracks for exterior shades, and a very, very minimal drip. This is, again, some of the details more fully
developed. You see with the cool shade on the left, that’s the tracks that overhang,
and this very, very elegant corner. Now part of our mandate, and here
is a view of an original window, and I just wanted to point out something that does not
appear on the drawings, but does appear in construction, which were these little stainless
steel clips because that’s something that we talked about in terms of when we got to
the point where we had to replace the glass as to whether or not those were to be replicated. This is a pretty good look at an original
installation as it stood about two years ago. Again the proportion of the wall, you can
see there the numbers laid out, so obviously we’re dealing with a very, very high energy
loads on this building. One of the things that people always talk about when we say
we’re working on this is, “Oh yeah, that’s the building that’s covered with tin foil”
because there was very little in the way of sun control that went along with this, and
that was again, part of our mandate. One of the things I just wanted to point out very
briefly is that there is also, in the slot between the towers, a very early use of an
IGU, these are the welded metal seams. Most of them, not all, but most of them had held
up very well. Certainly better than you would expect a contemporary IGU being 52, 53 years
down the road. Looking here, again, at the existing condition,
a typical section on the left, typical plan at that very, very elegant corner on the right,
and obviously a big energy, so one of the things that we had to do since
Penn, like many institutions, is trying to adhere to a mandate to achieve 30% energy
reduction in a fairly short period of time. There’s a large number of universities around
the country that have signed on to this, and so they’re looking at every project with the
idea of what can we do to be frugal, as Matt said, is possible. They weren’t demanding, but they said you
have to explore every alternative, so we did look. We said, “Okay, can we somehow mimic
these profiles in a thermally broken frame?” Well, there are two problems with this. One,
is the frame really is a little- Or three. The frame is a little bulkier, or maybe way
bulkier than we would want it to be. Two, and most important, you’re having to rip out
the original frame which means you are disrupting both the concrete frame, and the brick and
fill around it. Three, you still have the problem at the corner of the lack of a thermal
break, so it’s never going to be a perfect solution. We continue to develop, and again, looking
on the left, that’s the existing. In the center, is saying, “Okay, what if we keep the frame,
but still try to introduce an IGU?” This was just deemed to be too tenuous for a lot of
reasons, and a lot of that had to do with the fact of the distortion that was planned,
and it’s hard enough to take up distortion in a monolithic piece of glass, but to try
to do it in an IGU because none of the replacement lights of glass were actual rectangles. They
all had deformed corners of one kind of another. On the right, what we eventually came up with,
and this echoes a little bit of what Walter said yesterday, the use of high-performance
laminated glass- the idea that we could with a laminated glass, a significant improvement
and performance over the quarter-inch polished plate, a more permanent solution because it
does not have the problem of the degradation of the seals, and the ability to both put
an inter-layer in this which would help in terms of solar control, still invisible, and
keep it flat. It was very, very important, the flat quality of this glass, which you’re
not going to get with an IGU, and you’re not going to get with tempered glass because of
the roller wave phenomenon, but it is possible to do that with laminated glass. Here at the transom, one of the things we
had to deal with the laminated glass, which you see on the right, worries about the possible
exposure of that piece of film. At the intersection between that two lights, we did some testing
on that, it was determined not to be an issue with the glass, and so we went forward with
that. Matthew Chalifoux: Just quickly, we did do
energy analysis on the building overall, our engineers really drove this. This was helpful
in helping Penn come to grips with the decisions that they had to make. I didn’t mention before,
we had a number of constituencies at Penn. We worked for facilities in real estate services,
which is where the campus architect’s office is, but the building is occupied and essentially
owned by the School of Medicine, so the funding for the project came from the School of Medicine.
Their priorities weren’t all the same, in terms of what they’re trying to achieve out
of the project, but you can see we did do a study of different ways of looking at the
building, in terms of systems and glazing. This was an early pass at understanding what
kind of energy reductions we’re going to get from the design. Essentially the one on the
left was the existing energy usage, and the one on the right, was using chilled beams
with IGUs. You could see that’s obviously the best option in terms of energy reduction,
but the difference between that, and just using chilled beams with a laminated glazing,
wasn’t significant enough. The greatest energy savings was out of the mechanical systems
upgrades, and not out of the glazing. It allowed Penn to sit back and think that maybe the
preservation issues in this case were enough to drive the decision because they were getting
significant energy benefits out of the other elements of the design, and that satisfied
them. We also did testing on the windows. We wanted
to understand whether we were really achieving the improvements that we were planning on
doing. We did both air and water infiltration testing on the existing windows, and I always
like to say that they failed magnificently. The area filtration, based on the size of
the window and the configuration, we would be allowed about 18.5 CFM as an allowable
for a window installation. We’re over 35 and they could barely get that because they couldn’t
keep enough pressure in the chamber to figure out what the number was. On water penetration,
the test is supposed to run for 15 minutes. We stopped at 4 minutes 15 seconds because
we were probably going to flood the lab space below. The good news is that after the mock ups were
done, we retested the new installation, and the CFM is down to below 1, 1 CFM well below
what is allowable. Water penetration identified some weaknesses in workmanship that we were
going to have to deal with in full installations, but really was at a level that was low enough
that positive pressurization of the building with mechanical systems would deal with that,
was not going to be an issue. David N. Fixler: Now we’re getting to the
actual mock ups and installation. The first thing we did was look at the glass itself,
and because of the scale of these lights, we decided to make the glass choice prior
to fabricating the full 14 by 5 and a half foot units. We worked very closely with a
couple of glass manufacturers, eventually settling on Viracon, looked at both the VLE
70 and VLE 85, looked at combinations of low iron and clear glass against two layers of
clear glass, and a laminate, and finally came up with the closest match being the VLE 70
with a low iron on one side, and a clear glass on the other side, virtually identical to
the original in appearance, but much, much more robust. We also looked at, just in terms
of the restoration of the steel itself looking at that corner, the steel was in excellent
condition. There was no corrosion to speak of, and they were really the only things that
we really had to do with it was lightly clean it because it is this very matte finish that
Kahn would grow increasingly fond of as he worked through his career, this very, very
almost pewter-like stainless steel finish. It was really just a matter of re-passivating
the areas where we were going to be re-glazing, and doing a very, very light cleaning on the
rest of it. We did do a full corner mock up, two lights of glass and two of the big lights,
and all of the transom lights. Looking up at the corner, there you see it without the
clips. The reason we decided not to use the stainless steel clips is because they were
not part of Kahn’s original detailing. They were done for expediency because of concerns
about how well that corner could actually be sealed, and we didn’t feel it was honest
to put them back. They would be purely decoration. Frankly, it’s one of the things too, if anybody
feels strongly enough about it in the future, you can go up and glue them on which is all
they’d be anyway. The technology that one uses to put glass these days is far advanced
from what it was in 1961, and so we felt quite comfortable leaving it the way it is, and
as I say, more honest, a more honest approach. There was a lot of discussion about exactly
how to set these windows. We tried initially to do a mechanically fastened stop on the
inside. We spent literally hours in the field arguing over an 8th 16th of an inch tolerances
and dimensions to try to get this to be just right. In the end what we ended up with was
a structural silicone sealing. We’re using a Dow 995 silicone to set the windows. The
aluminum stop is adhered with a 020 VHB tape, but it really is not performing any structural
function at this point. Here is the midst of that discussion that I talked about where
we were looking at this. I think it’s a tribute to the designer, the specific designer of
the glazing, Aaron Davis, he’s there on the left from [inaudible 00:24:30]. I think also to the fabricator and installator,
the people who put these things in and who were able to get the tolerances to such a
way to accommodate all the deformation in a way that still pass, as Matt said, the test
that we’ve run on these windows post installation. Here’s where we are today where the windows
have been installed. They are temporarily braced until we get the stops, and just as
a matter of precaution, but really the building from the outside doesn’t look any different,
it just looks a little bit cleaner. I think once we’re done on the inside, if you’re going
to notice differences, it will be elsewhere in the building, and not on the glazing. Thanks.

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