Fabricating Environmental Comfort
2012 PDCI Seed Grant Report
Jeff Ponitz
7 January, 2013
Fabricating Environmental Comfort
2012 PDCI Seed Grant Report
Jeff Ponitz
Assistant Professor
Department of Architecture, Cal Poly San Luis Obispo
jponitz@calpoly.edu
Abstract
Environmental comfort is critical to productivity in working and learning environments, which are
often expansive, undifferentiated spaces where users have little or no control over their personal
space. This research focuses on performative ceiling systems as a means for positively impacting
environmental comfort in working and learning spaces. Digital and physical processes of design,
analysis, and fabrication are integrated in the development of prototypes for ceiling systems that
control airflow, sound, and light to create zones of comfort—defined not only in terms of thermal,
acoustic, and photometric performance, but also in aesthetic and psychological terms.
The aim of this research is to determine design criteria for environmental comfort in a particular
context—learning and working spaces—and to develop prototypes for ceiling systems that employ
innovative design and fabrication processes to address various criteria for comfort in these
spaces. Multiple design iterations are prototyped and comparatively evaluated.
Introduction: Defining Environmental Comfort
Environmental comfort is a phenomenon with myriad definitions. Ambient environmental conditions
such as light, sound, heat, and moisture figure prevalently into most definitions of environmental
comfort, however, it should be acknowledged that the notion of comfort is fluid across time
(thermostats are set differently in the winter than the summer), use (a concert hall has different
acoustic goals than an open office), and user (one person wears a t-shirt while another wears a
sweater). Environmental comfort implies a shifting range of conditions, rather than a one-size-fits
all target, which makes it difficult to test and difficult to design for. This is especially true in settings
where large numbers of unknown people gather unpredictably; examples of these types of
environments include offices spaces, meeting rooms, classrooms, libraries, event spaces, and
restaurants. This research focuses on the more institutional spaces of larger working and learning
environments. These spaces are often characterized by open floor plans that maximize square
footage and flexibility; furniture is often the primary means of defining establishing zones of
gathering vs. solitude, work vs. play, and walking vs. standing vs. sitting, but has a modest effect
on environmental comfort beyond task lighting and the acoustic absorption of upholstery. Typically
in these spaces, a suspended ceiling system assumes these responsibilities.
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Fabricating Environmental Comfort
2012 PDCI Seed Grant Report
Jeff Ponitz
7 January, 2013
Ceilings are often referred to as “the fifth wall” in a room; in a large, open-plan environment, they
often feel like the only wall, extending endlessly over a sea of furniture. The most common strategy
for concealing mechanical, electrical, and plumbing equipment, while selectively giving users
access to these services, is the acoustic ceiling tile (ACT). ACT is much-reviled for its relentlessly
repetitive grid, its bland and homogenous appearance, its use of cheap and unidentifiable
materials, and more than anything its association with places no one wants to inhabit, but ACT is
ubiquitous because it is inexpensive, can be used in a wide range of settings, easy to maintain,
and does an adequate job of providing light and air to users while attenuating background noise.
ACT is also somewhat flexible in that any acoustic tile can be replaced by a lighting tile, or an air
return tile, but this customization only works as an either/or proposition: it only performs in one way
at any given moment, which forces a series of 2’ x 2’ compromises resulting in an uneven
distribution of light, sound, and airflow. Despite its limitations and reputation, ACT is an ingenious
and useful system that has become a victim of its own success, and today there exist several highend ACT systems featuring quality finishes and fixtures.
The goal of this research was not to critique or replace ACT, but rather to imagine alternate ways of
controlling light, sound, and airflow through ceiling systems. In contrast to ACT’s rigid (and visually
prominent) segregation of acoustic treatment, lighting, and air distribution, this research aimed to
incorporate these functions into a visually cohesive, continuously differentiated system. Designing
and prototyping high-performance systems was a central goal of this research, but there is a
second aspect of environmental comfort, equally important to ambient conditions, that is often
neglected in these settings: the psychological and emotional experience of a space. Is a space
inviting? Does it feel open yet personally scaled? Does it inspire contemplation, conversation,
dreaming, action? Does it make us not just comfortable, but happy? This research attempted to
negotiate this quality of experience with a range of environmental performance criteria, as well as
issues of constructability, craft, and material efficiency.
Site
In order to ground and contextualize these research goals within the larger typology of open
learning/working spaces, Cal Poly’s Kennedy Library was used as a test site for this research. A
concrete frame building constructed in the Brutalist style in 1980, the library features 22’-6” column
bays and 13’-6” high exposed coffered ceilings, creating a spare framework that has been filled
with ductwork, suspended fluorescent light fixtures, and conduit above; there is currently no
acoustic treatment. Because it is in a seismically active region and lacks fire sprinklers, the library
also presents strict code and safety requirements (no loose hanging connections, no combustible
materials) that must be followed. Discussions with library administrators, staff, and students
painted a picture of a space that, while possessing good bones, is generally unloved and at times
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Fabricating Environmental Comfort
2012 PDCI Seed Grant Report
Jeff Ponitz
7 January, 2013
dysfunctional. These complaints were particularly acute in the area surrounding the library café,
where the concrete structure feels cavernous, undifferentiated, and unwelcoming; and the
adjacent social working space, often used for public presentations, where excessive noise and
echoes prevent speakers from being intelligible. These two zones of the library, spatially
contiguous but programmatically diverse, provide an excellent context in which to test the
continuously differentiated performance and feel of a ceiling system.
Design Strategies
In order to design with environmental comfort in mind, basic phenomena of sound, light, and
airflow were researched and a series of design strategies were outlined that would consider both
ambient conditions and the human experience.
Multi-Scalar Design
Performance criteria should be addressed at a variety of scales to maximize their effect. For
example, the acoustic performance of a given architectural surface is governed by its material
composition (density, molecular structure, interconnectedness of internal voids), its texture
(smooth/regular causes echoing, rough/irregular disperses sound), its orientation (understood as a
larger-scale texture), and its placement in space (higher ceilings increase reverberation time)
Layered Approach
Different materials offer different performative advantages, and multiple materials must be layered
in order to meet a wide variety of performance criteria. For example, open-cell foam’s low density
and high elasticity make it ideal for acoustic treatment, but is not structural, is not durable, and is
difficult to clean. Sheet aluminum is rigid, durable, and easy to clean, but acoustically reflective.
The strategic combination of these materials could harness the strengths of each while mitigating
their weaknesses.
The More Surface Area the Better
More acoustically absorptive material absorbs more sound; pleats or folds in a ceiling surface will
increase surface area. Just as importantly, that surface area must remain accessible to the sound
force: closed ACT ceilings do not permit sound into the ceiling cavity, meaning they only absorb
sound on one face. By remaining exposed and open on all sides, “acoustic cloud” products utilize
their entire surface area and absorb twice as much sound as closed ACT systems. The ideal
ceiling system in these terms would have a pleated or undulating surface with substantial openings
to above.
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Fabricating Environmental Comfort
2012 PDCI Seed Grant Report
Jeff Ponitz
7 January, 2013
Varied Surface Orientation and Height
Not all sound can be absorbed, and much of it will be reflected by the ceiling. Parallel reflections
cause echoes; surfaces with varying orientation and height will disrupt and disperse these
reflections. Surfaces that are angled in a single direction (such as a saw-tooth pattern) will still
result in uniform reflection, so variation in at least two planes is necessary. Rounded surfaces
(such as domes or barrel vaults) will create focal points of reflection. It would follow that the ideal
solution would be a “controlled randomness”. Varied ceiling heights also encourages the
openness of the system overall, and creates implied spatial zones.
The above design strategies were synthesized to produce the following design statement for the
ceiling system:
A dynamically-formed surface, porous at both the micro-scale and the macro-scale. It is rigid and
reflective on the bottom, soft and absorptive on top, with a high degree of permeability between.
The surface continually differentiates itself to collect and selectively distribute energy, serving as
light fixture, air diffuser, and sound while creating implied spatial zones below.
This design statement, while giving clear direction to the research, did not predetermine a
particular material or form; a series of design studies were used to quickly explore and test
different versions and variations of the design statement, with the added considerations of material
size and cost, manufacturing and assembly processes, cost, and ease of installation and
maintenance (changing a light bulb proved to be among the most difficult of these). From these
design studies, two primary iterations emerged, each based on a process of material
transformation.
Expanded Surface Iteration
Expanded metal is commonly used for utilitarian elements such as guardrails, grates, and outdoor
furniture. It is manufactured by slitting and stretching a continuous metal surface to increase its
surface area and its porosity. Expanded metal looks similar to perforated metal, but it has a much
greater material efficiency: it yields a surface area greater than the initial sheet, where perforation
creates material waste and yields the same surface area as the initial sheet (“you don’t pay for the
holes” is a common expanded metal sales pitch). Perhaps more importantly, the expanding
process—a nuanced rotational stretching produced by oppositional sets of teeth—produces a
depth of surface that increases the sheet’s rigidity, whereas perforation reduces it.
This material process served as the basis of an exploration of customized and variably expanded
surfaces applied to ceiling system. In contrast to the goal of most industrially manufactured
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Fabricating Environmental Comfort
2012 PDCI Seed Grant Report
Jeff Ponitz
7 January, 2013
expanded surfaces—relatively flat and uniformly porous sheets—the goal of this research was to
create volumetric enclosures with varying degrees of porosity. Parametric design software was
used to generate a wide range of cut patterns, which could be laser cut out of paper. The
parametric model was used to vary the beginning and ending profiles of the slits, the number of
slits between these profiles, and the spacing of the slits in two directions, in order to understand
how each of these variables affected the expansion process as well as the resultant volume. Rapid
prototyping of these variables revealed that a relatively small spacing between slits was required
for any significant expansion to occur; contrary to expectations, the most rigid volumes were those
with the most slits. This likely resulted from the redundant network of many small pieces of
material, stiffening the surface in more directions. These expanded slits could be thought of as
structural perforations. Increased slits also resulted in larger volumes: the finest mesh allowed for a
sheet to expand to over 24” in depth while maintaining its 8x10” footprint.
expanded paper surface studies
These small paper prototypes demonstrated that expanded surfaces have the potential to be
expanded volumes that are at once strong, lightweight, porous, and materially efficient. Aluminum
would be a natural choice for these volumetric elements at an architectural scale, given its ductility
and rigidity; as applied to a performative ceiling system, these volumes have the potential to
aggregate into a larger surface with varying depth and permeability, serving as a screen to lighting,
HVAC, and acoustic material above. The expansion process creates an incredible variety of
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Fabricating Environmental Comfort
2012 PDCI Seed Grant Report
Jeff Ponitz
7 January, 2013
surface orientations and depths that could effectively reflect light and direct airflow, while
remaining permeable to acoustic material above.
A further exploration of expanded surfaces, named thermoslump expansion, pursued an alternate
approach to materials and fabrication processes. PETg plastic, commonly used as a packaging
material, was laser cut with multiple nested slit patterns and set into a rigid frame that constrained
the perimeter geometry of the sheet. This assembly was then heated to PETg’s melting point, at
which point the plastic slumped under its own weight, resulting in compound catenary volumes
informed by the pre-cut expanding pattern. An identical cut pattern produced four spatially unique
panels, based on the temperature and duration of their heating. This exploration was quickly
deemed incompatible with the immediate goal of a ceiling system due to non-compliance with fire
code—a ceiling that melts and descends at a relatively low temperature would pose a serious
safety threat in event of a fire—but it shows enough promise in other applications to be revisited in
future research.
Thermoslumped expanded PETg surface studies
While the surface articulation of the expanded surface iteration produced promising structural and
environmental performance, it has not yet yielded a satisfactory spatial effect at the scale of the
larger ceiling assembly. The aggregation of these autonomous, box-like volumes echoes the
gridded monotony of existing ACT systems. To those ends, this iteration does show potential as a
system for retrofitting existing ACT systems; it could lay into existing 2’x4’ metal-tee grids as a
performative upgrade over conventional tiles, and if the depth of expansion remained subtle, could
result in a pleasantly quilted appearance.
Folded Surface Iteration
The second design iteration explored the potential of folded surfaces to simultaneously create
rigidity, variable surface orientation, and spatial definition. Inspired by origami, this iteration began
with simple folded paper surfaces; a single slit was introduced to this surface prior to folding to
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Fabricating Environmental Comfort
2012 PDCI Seed Grant Report
Jeff Ponitz
7 January, 2013
create an aperture that also increased the overall surface depth. Aluminum was again a logical
material for this system due to its ductility, rigidity, and machinability.
Folded paper surface studies
Parametric folding simulations of panels (top) and assembly (bottom)
Again, parametric design software was used to simulate and evaluate variables to the system,
controlling the folding angle as well as surface width and length, and allowed for the visualization
of this folding process at the scale of an aggregated system, rather than a single module. Beyond
visualization, this parametric model was vital in negotiating several critical constraints: the spacing
of the Kennedy Library columns (22’-6” on-center), the spacing of the existing fluorescent light
fixtures (6’-2” on-center), and the maximum practical dimensions of sheet aluminum (4’x6’). Each
variable independently affected the spatial and dimensional outcome of the system, so the
parametric model was instrumental in finding the moment where all constraints aligned. A single
Kennedy Library column bay of this system was rapidly prototyped using a 3D printer.
3D printed model of folded surface iteration
The resultant folded surface could be broken down into a series of diamond-shaped forms that
alternate between concave and convex geometries; the convex diamonds, aligning with existing
light fixtures, were referred to as “light diamonds” while the concave diamonds, aligning with air
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Fabricating Environmental Comfort
2012 PDCI Seed Grant Report
Jeff Ponitz
7 January, 2013
returns and future acoustic material, were referred to “sound/air diamonds”. The subtle formal
differentiation of these aluminum diamonds, and the varied systems above them contents above
them, would create a ceiling system that is both unified and dynamic. The large-scale apertures
between diamonds, as well as a small-scale perforation system within them, create an acoustically
transparent framework that allows sound to reach acoustic foam on all sides. Apertures and
perforations also serve to diffuse light and air.
Folded diamond assembly model with acoustic backing
Section through Kennedy Library column bay
Perspective of Kennedy Library column bay with folded iteration
Architecturally scaled folded plate systems are typically difficult to realize: the translation from a
single sheet of paper to several panel components often compromises not only the structural
integrity of the fold, but also its seamless appearance. In this instance, the diamond
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Fabricating Environmental Comfort
2012 PDCI Seed Grant Report
Jeff Ponitz
7 January, 2013
subassemblies were a natural breaking point for the overall surface; these subassemblies were
further broken down into four triangular panels, each with a single fold, measuring approximately
3’-6” x 5’-6” flat. A series of folded tabs at the panel edges act as structural flanges as well as
connection points, joining adjacent panels to each other and the diamond subassemblies to a
hanger rod. In Kennedy Library, the diamonds would be hung from the existing suspended steel
channels which support the current light fixtures; these fixtures would be relocated to the top of the
diamonds. Again, translating simple paper folds such as these flanges to full-scale sheet
aluminum proved a challenge; a folding jig was designed and constructed to maintain the rigidity
and geometry of the panel edges during folding.
Folding jig
The folded surface iteration was successful in its overall spatial effect, creating a sculpturally
rhythmic surface with ample porosity. A wide range of perforation patterns, customized for different
environments, could successfully modulate light, sound, and airflow, but it should be noted that
perforation detracts from the structural performance of the folded panel. The simplicity of varying
folding angles in a system to control its overall porosity—giving it the potential to appear as a
nearly flat closed surface, or a highly sculptural open one—is intriguing, and also suggests the
possibility that the system could be designed to be operable. While animation of the parametric
model was used as a design tool for this iteration, it could alternately be seen as a real-time
simulation of a kinetic system that opens and closes to respond to environmental stimuli such as
occupant load or noise levels. This alternate scheme was outside the scope of this research, but
has potential for further research and development.
Hybrid Iteration
The expanded and folded iterations demonstrated complementary strengths and weaknesses. The
expanded iteration excelled at the scale of the individual surface, providing more rigidity, more
varied reflection, and more material efficiency, while the folded iteration was compromised by its
perforation. Conversely, the folded iteration excelled at the scale of the aggregated assembly,
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Fabricating Environmental Comfort
2012 PDCI Seed Grant Report
Jeff Ponitz
7 January, 2013
creating a performatively sculptural assembly, where the expanded iteration recalled the less
desireable qualities of ACT systems. The two iterations were combined into a third, hybrid iteration
that attempted to play the strengths of each system off the other. The overall geometry and rhythm
of the folded iteration was preserved; folds and perforations were replaced with slits that would
allow each diamond panel to expand into a form roughly similar to the folded panel.
This hybridization of schemes showed promise in a ¼ scale prototype made out of 22-gauge
aluminum, creating undulating structural surfaces, but proved very difficult to fabricate at full scale
from 12-gauge aluminum; expanding the surface without destroying the panel was nearly
impossible. This was largely due to the physical constraints of expanded surfaces: expansion slits
ideally either extend to the edges of a sheet (as in typical expanded metal sheets) or are arranged
in concentric closed geometries (as in the original expanded iteration), but neither was desirable
for the hybrid iteration. It is quite possible that continued exploration of both the design and the
fabrication of this system will yield better results: using a thinner gauge aluminum, modifying slit
geometry and density, and refining the folding/expansion jig could all lead to a more cleanly and
easily expanded surface.
Hybrid iteration ¼ scale prototype (top) and full-scale expansion attempt (bottom)
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Fabricating Environmental Comfort
2012 PDCI Seed Grant Report
Jeff Ponitz
7 January, 2013
Conclusion and Next Steps
Ceiling systems are most underutilized where they are most needed, both performatively and
aesthetically: the open, undifferentiated expanses of many working and learning environments.
This research attempted to exploit ceilings’ potential for addressing multiple definitions of
environmental comfort. To this point, the design studies have produced two primary directions for
further development: a lay-in tile system based on the expanded surface studies, and a point-hung
cloud system based either on the folded surface system or a hybrid of the folded and expanded
surface research. Both of these systems could be seen as a strategy for retrofitting existing
spaces, or as components of new construction; the lay-in tile system would likely be more suited
for retrofits, tight spaces, and lower budget projects, while the suspended cloud system would
likely be used for larger spaces, and higher budget projects.
While this report marks the conclusion of the PDCI Seed Grant, it by no means marks the end of
the larger body of work. The next steps for this research are as follows:
Continue to prototype both systems in order to further develop the craft and precision of the
assemblies, connection details, integration of acoustic/lighting/HVAC systems, and installation
sequences. Part of this work will be to refine the workflow that translates a digital file into a finished
material assembly: learning to digitally simulate complex material processes such as irregularly
expanding surfaces will be crucial to making a product that is predictable and controllable.
Fabricate and install a full-scale prototype in Kennedy Library, and thoroughly document its
performance, including how it diffuses light and air, and how it absorbs sound. These activities
were proposed as part of the Seed Grant proposal, but in retrospect it was entirely unrealistic to
proceed through the entire design, prototyping, fabrication, installation, and testing process given
the amount of time and funding. Only after completing the work for this seed grant did I fully grasp
what makes a seed grant special: the opportunity to generate and develop new ideas that may
then fuel further research.
Pursue tangential avenues of research that arose during this work, notably that of a responsively
operable folded system and that of a thermoslumped expanded surface. Each of these will require
knowledge, tools, and time that were not feasible during the course of this grant, but each could
open up new possibilities for ceiling systems or other research.
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Fabricating Environmental Comfort
2012 PDCI Seed Grant Report
Jeff Ponitz
7 January, 2013
Acknowledgements
I am grateful to the PDCI for its funding of this course of research, very crucial at this “seed” stage
of what I believe is a long trajectory of research. Any research that involves full-scale prototyping
and material experimentation is nearly impossible without initial funding.
I would also like to thank the people at Kennedy Library—specifically Anna Gold, Dale Kohler,
Jesse Vestermark, Karen Lauritsen, and Sarah Cohen—for their enthusiastic support of this
research, and their patience in overseeing a complex design-build process on a professor’s
timeline.
Lastly, I would like to thank research assistants Nicholas Batie, Gustavo Bermudez, Joel Piazza,
and Jason Schmidt for their contributions at various stages of the work.
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