From research to practice: Build a better envelope

Submitted by digital on Wed, 04/06/2016 - 20:37
{"version":"0.3.0","atoms":[],"cards":[],"markups":[["a",["href","http:\/\/\/","target","_new"]],["a",["href","http:\/\/\/2030_challenges\/2030-challenge\/","target","_new"]],["a",["href","http:\/\/\/nibs\/february_2016?pg=11#pg11","target","_new"]],["a",["href","http:\/\/\/uploads\/research_project\/1416244116-0d52d646c2431daf2\/2012_AIA UPJOHN GRANT_Thermal Performance of Facades_Payette Final Report.pdf","target","_new"]],["strong"],["em"]],"sections":[[1,"p",[[0,[],0,"Incorporating a scientific\nprocess into architectural practice leads to higher performing buildings that\nembody sustainable design. Using research to inform design decisions can have\nfar-reaching impacts on the built environment. At "],[0,[0],1,"Payette"],[0,[],0,", our research not\nonly serves as a useful PR tool, it also becomes part of our internal firm-wide\neducation. The topics and methods we use in our research fundamentally shape\nthe way in which the entire design staff thinks about and approaches\narchitecture."]]],[1,"p",[[0,[],0,"Payette\u2019s in-house Building\nScience Group is at the heart of our research. In addition to conducting\nresearch on their own, group members develop research projects to collaborate\non with our design staff. Over half of the staff has worked on a research\nproject in the past three years. Each designer spends a few hours per week\nfocused on a research project, including regular meetings with their research\nteam. These projects are typically completed in six to nine months, at which\ntime we document and share our findings internally and externally via our\nwebsite, blog, publications and conference presentations."]]],[1,"p",[[0,[],0,"While our research has\ncovered a diverse range of topics, the primary focus has been on envelope\nperformance. As a signatory of the "],[0,[1],1,"2030 Challenge"],[0,[],0,", we are committed to making\nour buildings as energy efficient as possible.\nRecently, we completed two research projects that have played a major role in\nimproving our understanding of and approach to building envelope design."]]],[1,"h3",[[0,[],0,"Thermal Comfort"]]],[1,"p",[[0,[],0,"When designing facades that\nhave large glazed openings, a mechanical system, such as perimeter radiant\nheating, is typically used to offset heat loss through the envelope and ensure\noccupant comfort in cold climates. However, as glazing properties have\nimproved, as measured by U-value, our research questioned the widespread use of\nmechanical systems that have upfront and operational costs. There are two\nissues that can affect occupant comfort in wintertime: downdraft and radiant\ndiscomfort."]]],[1,"p",[[0,[],0,"Both downdraft and radiant\ndiscomfort are a function of the window proportions and glazing properties. For\ndowndraft, warm interior air hits the cold glass surface and forms convective\nair currents that can make an occupant feel cold. As the glazing height\nincreases, this issue becomes more acute. For radiant discomfort: if there is a\nlarge glass surface adjacent to an occupant (i.e. floor-to-ceiling glass), or\nif the window is poorly performing, a person will feel uncomfortable. We\nquantified these issues through a series of simple charts that graph the window\nU-value as a function of the window proportions. These graphs show how certain combinations\nof U-value and window proportions can ensure occupant thermal comfort without\nthe use of perimeter radiant heating."]]],[1,"p",[[0,[],0,"Project teams are using\nthese simple charts early on in the design process. At this stage, fa\u00e7ade\nwindow proportions and placement can be adjusted to eliminate the need for\nperimeter radiant heating. Also, design teams are now able to better understand\nthe tradeoff between the U-value of glazing and the window size and how that\naffects occupant thermal comfort."]]],[1,"blockquote",[[0,[2],1,"Read more about our\nresearch on thermal comfort and glazing."]]],[1,"h3",[[0,[],0,"Thermal Bridging"]]],[1,"p",[[0,[],0,"Thermal bridging occurs\nwhen thermally conductive materials penetrate through a building\u2019s insulation\nlayer, creating areas of reduced resistance to heat transfer. While most\narchitects are aware of thermal bridging, there is little hard data about its\nimpact on building performance."]]],[1,"p",[[0,[],0,"Our research focused on\nfirst quantifying how our own buildings were performing against their intended\ndesign. Using a thermal imaging camera, we took thousands of images looking for\nconditions with thermal bridges. We then studied proposed improvements to\ncommon details and conditions."]]],[1,"p",[[0,[],0,"We established the intended\nperformance of each assembly through traditional one-dimensional R-Value\ncalculations, and then compared that against the observed performance.\nGenerally, our building envelopes performed 40 percent to 60 percent less than\nthe intended design. Finally, using the 2-D heat flow simulation tool, THERM,\nwe explored alternative details aimed at improving performance."]]],[1,"p",[[0,[],0,"As a recipient of 2012\u2019s\nUpjohn Research Grant, we were able to focus significant attention on this\nimportant research topic. This has not only heightened an awareness of the\nissue internally, but has also directly impacted the way we attach fa\u00e7ade\nsystems, and how we detail transitions and penetrations."]]],[1,"p",[[0,[],0,"Today, we use THERM as a\ndesign tool and we also specify new materials, systems and products that\naddress thermal bridging. Additionally, we work with our engineers to\nincorporate structural thermal beaks in canopies, overhangs and roof\ndunnage. By leveraging technology and a better understanding of the real\nimpact of common thermal bridges, we have been able to move our practice beyond\nstandard design and make a significant impact on the performance of our\nenvelopes."]]],[1,"p",[[0,[],0,"The culmination of this\nwork is a report "],[0,[3],1,"freely available for\ndownload"],[0,[],0,"."]]],[1,"p",[[0,[4],1,"About the Authors"]]],[1,"p",[[0,[5],1,"Jeff Abramson, AIA, LEED AP, is an associate at Payette; Jenny Ratner, \nLEED AP, is a designer at Payette; and Lynn Petermann, AIA, LEED AP, is an architect at \nPayette."]]],[1,"p",[[0,[],0,"\n\n\n\n"]]],[1,"p",[[0,[],0,"\n\n\n\n"]]],[1,"p",[[0,[],0,"\n\n\n\n"]]],[1,"p",[[0,[],0,"\n\n\n\n"]]],[1,"p",[[0,[],0,"\n\n\n\n"]]],[1,"p",[[0,[],0,"\n\n\n\n"]]],[1,"p",[[0,[],0,"\n\n\n\n"]]]]}
Three members of Boston’s Payette firm describe its use of research to improve building envelope design.
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