Evaluation of Alternate Metal Stud Framing to Reduce Thermal Bridging in Exterior Walls

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Title:
Evaluation of Alternate Metal Stud Framing to Reduce Thermal Bridging in Exterior Walls
Physical Description:
1 online resource (130 p.)
Language:
english
Creator:
Bennett,Brian K
Publisher:
University of Florida
Place of Publication:
Gainesville, Fla.
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Thesis/Dissertation Information

Degree:
Master's ( M.S.B.C.)
Degree Grantor:
University of Florida
Degree Disciplines:
Building Construction
Committee Chair:
Srinivasan, Ravi
Committee Co-Chair:
Muszynski, Larry C
Committee Members:
Issa, R. Raymond

Subjects

Subjects / Keywords:
aerogel -- bridge -- bridging -- conduction -- dimpled -- exterior -- framing -- metal -- ridged -- rinker -- slit -- stud -- thermal -- wall
Building Construction -- Dissertations, Academic -- UF
Genre:
Building Construction thesis, M.S.B.C.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract:
Thermal bridging is a transfer of energy through the most thermally conductive material in an otherwise well insulated assembly. In the case of exterior building walls constructed with metal studs, the steel framing is the path of least resistance of thermal energy within the system. As a consequence, the thermal performance of the exterior wall system is degraded and higher energy costs are incurred. The purpose of this thesis is to evaluate several innovative materials and products that appear capable of significantly reducing the thermal bridging effect experienced in exterior metal stud framing. This research evaluates and compares these products, based upon their thermal performance and associated costs as components within an exterior wall system. The heat conduction properties of each of the alternative products were determined using two-dimensional heat transfer analysis software as components within a Code-minimum compliant wall system assembly. The U-factors of each of the wall assemblies were then entered into a building energy simulation model based upon the design of Rinker Hall at the University of Florida to project annual energy savings based upon the anticipated heating and cooling loads resulting from exterior wall heat conduction. To further understand how climatic variances could affect thermal performance, simulations were created for each of the energy models in each of eight US climatic zones. The national average for the cost of electricity per unit in kilowatt hours was then applied to the energy loads determined for each model. Additionally, cost estimates were prepared for of the wall type assemblies to understand the initial cost implications associated with the alternative products. The energy load differentials were then applied to life cycle cost analyses to determine the overall cost effectiveness of each of the alternative products over an extended period of 40 years. This process took initial costs, projected energy savings, interest rates (loan, discount and energy inflation) to determine which of the products, if any, would be recommended by this study.
General Note:
In the series University of Florida Digital Collections.
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Includes vita.
Bibliography:
Includes bibliographical references.
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Description based on online resource; title from PDF title page.
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This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility:
by Brian K Bennett.
Thesis:
Thesis (M.S.B.C.)--University of Florida, 2011.
Local:
Adviser: Srinivasan, Ravi.
Local:
Co-adviser: Muszynski, Larry C.

Record Information

Source Institution:
UFRGP
Rights Management:
Applicable rights reserved.
Classification:
lcc - LD1780 2011
System ID:
UFE0043414:00001


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1 EVALUATION OF ALTERNATIVE METAL STUD FRAMING TO REDUCE THERMAL BRIDGING IN EXTERIOR WALLS By BRIAN KEVIN BENNETT A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN BUILDING CONSTRUCTION UNIVERSITY OF FLORIDA 2011

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2 2011 Brian Kevin Bennett

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3 To my mom without whom I would not be here today

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4 ACKNOWLEDGMENTS I would like to thank Dr. Srinivasan Dr. Mus z ynski and Dr. Issa for taking the time to serve on my committee and assist with this research. Particular gratitude is extended to Dr. Srinivasan for his guidance, support and patience during my efforts to complete this thesis. I thank my sons, Kyle and Michael. They are my life and the motivation in all that I do. When I am uncertain and feeling blue, all I have to do is imagine their beautiful faces, and I am reinvigorated and ready to take on the world one more time. Above all others, I woul d like to thank my mom Evelyn Bennett for all of her amazing love and support. She picked me up when I was at my lowest and has kept me walking ahead My mother is my greatest blessing

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5 TABLE OF CONTENTS Page ACKNOWLEDGMENTS ................................ ................................ ................................ ............... 4 LIST OF TABLES ................................ ................................ ................................ ........................... 7 LIST OF FIGURES ................................ ................................ ................................ ......................... 9 CHAPTER 1 INTRODUCTION ................................ ................................ ................................ .................. 13 Background ................................ ................................ ................................ ............................. 13 Statement of Purpose ................................ ................................ ................................ .............. 14 Objectives ................................ ................................ ................................ ............................... 14 2 LITERATURE REVIEW ................................ ................................ ................................ ....... 16 The Buil ding Envelope ................................ ................................ ................................ ........... 16 Exterior Wall Systems ................................ ................................ ................................ ............ 17 Wall types ................................ ................................ ................................ ............................... 17 Heat Transfer ................................ ................................ ................................ .......................... 21 U Factor Determination ................................ ................................ ................................ .......... 23 Parall el Flow Method ................................ ................................ ................................ ...... 25 Isothermal Planes Method ................................ ................................ ............................... 25 Modified Zone Method ................................ ................................ ................................ .... 25 2D Heat Flow Analysis ................................ ................................ ................................ ... 26 3D Hea t Flow Analysis ................................ ................................ ................................ ... 27 Equivalent Wall Model ................................ ................................ ................................ .... 27 Testing ................................ ................................ ................................ ............................. 27 Energy Analysis ................................ ................................ ................................ ...................... 28 Economic Analysis ................................ ................................ ................................ ................. 29 Initial & Future Expenses ................................ ................................ ................................ 29 Residual Value ................................ ................................ ................................ ................. 30 Study Period ................................ ................................ ................................ .................... 30 Real Discount Rate ................................ ................................ ................................ .......... 30 Constant Dollars ................................ ................................ ................................ .............. 31 Present Value ................................ ................................ ................................ ................... 31 3 RESEARCH METHODOLOGY ................................ ................................ ........................... 33 Overview ................................ ................................ ................................ ................................ 33 Step 1: Identificat ion of Alternative Materials ................................ ................................ ...... 34 Step 2: Material Properties ................................ ................................ ................................ .... 34 Step 3: Energy Analyses ................................ ................................ ................................ ........ 36

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6 Step 4: Cost Analyses ................................ ................................ ................................ ............ 38 4 RESULTS AND ANALYSES ................................ ................................ ............................... 39 Overview ................................ ................................ ................................ ................................ 39 Section One: Alternative Metal Framing Solutions ................................ ............................... 39 Ridged Flanged Studs ................................ ................................ ................................ ...... 40 Slit Web Studs ................................ ................................ ................................ ................. 42 Aerogel Strips ................................ ................................ ................................ .................. 44 Dimpled Flange Studs ................................ ................................ ................................ ..... 45 Ceramic Coated Studs ................................ ................................ ................................ ..... 47 Section Two: U Factors ................................ ................................ ................................ ......... 49 Parallel Path Method Results ................................ ................................ ........................... 50 Isothermal Planes Method Results ................................ ................................ .................. 51 2D Heat Flow Analysis ................................ ................................ ................................ ... 51 Section Three: Energy Analyses ................................ ................................ ............................ 52 Section Four: Cost Analyses ................................ ................................ ................................ .. 53 Energy Costs ................................ ................................ ................................ .................... 53 Construction Costs ................................ ................................ ................................ ........... 54 Life Cycle Costs ................................ ................................ ................................ .............. 55 5 SUMMARY, CONCLUSIONS AND RECOMMENDATIONS ................................ .......... 57 Summary ................................ ................................ ................................ ................................ 57 Matrix of Results ................................ ................................ ................................ .................... 58 Conclusions ................................ ................................ ................................ ............................. 60 Limitations ................................ ................................ ................................ .............................. 60 Recommendations for Future Study ................................ ................................ ....................... 60 A U FACTOR CALCULATIONS PARALLEL PATH METHOD ................................ ....... 62 B U FACTOR CALCULATIONS ISOTHERMAL PLANES METHOD ............................. 64 C U FACTOR CALCULATIONS 2D HEAT FLOW ANALYSIS ................................ ....... 66 D DECREASED HEATING LOADS FROM WALL CONDUCTION ................................ ... 70 E DECREASED COOLING LOADS FROM WALL CONDUCTION ................................ ... 73 F ANNUAL ENERGY SAVINGS ................................ ................................ ............................ 76 G LIFE CYCLE COST ANALYSES ................................ ................................ ......................... 79 LIST OF REFERENCES ................................ ................................ ................................ ............. 127 BIOGRAPH ICAL SKETCH ................................ ................................ ................................ ....... 130

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7 LIST OF TABLES Table page 4 1 R values and U factors using ASHRAE Table 5 H calculation methods ......................... 49 4 2 Total decreased energy loads from wall conduction (kWh) ................................ .............. 52 4 3 Projected annual energy savings ................................ ................................ ........................ 54 4 4 Construction unit costs per sf of opaque exterior wall area ................................ ............... 55 4 5 Estimated years to reach breakeven. ................................ ................................ .................. 55 5 1 Matrix of results ................................ ................................ ................................ ................. 58 A 1 Code minimum wall U factor. Parallel path method ................................ ........................ 62 A 2 Rinker exterior wall U factor. Parallel path method ................................ ......................... 62 A 3 Slit web, ridged & dimpled flange stud wall U factors. Parallel path method .................. 62 A 4 Aerogel strip wall assembly U factor. Parallel path method ................................ ............. 63 A 5 Thermal ceramic coated stud assembly U factor. Paralle l path method ............................ 63 B 1 Code minimum exterior wall U fa ctor. Isothermal planes method ................................ .. 64 B 2 Rinker Hall exterior wall U fa ctor. Isothermal planes method ................................ ......... 64 B 3 Slit web, ridged & dimpled flange wall U fa ctors. Isothermal planes method .................. 64 B 4 Aerogel strip wall assembly U f actor. Isothermal planes method ................................ ..... 65 B 5 Thermal ceramic coated stud assembly U factor. Isothermal planes method. .................. 65 D 1 Decreased heating loads. Heating loads. Zone 1 Miami, FL ................................ ......... 70 D 2 Decreased heating l oads. Zone 2 Gainesville, FL ................................ .......................... 70 D 3 Decreased heati ng loads. Zone 3 Atlanta, GA ................................ ................................ 70 D 4 Decreased heati ng loads. Zone 4 Seattle, WA ................................ ................................ 71 D 5 Decreased heating loads. Zone 5 Chicago, IL. ................................ ............................... 71 D 6 Decreased heat ing loads. Zone 6 Helena, MT ................................ ................................ 71

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8 D 7 Decreased hea ting loads. Zone 7 Minot, ND ................................ ................................ .. 72 D 8 Decreased he ating loads. Zone 8 Nome, AK ................................ ................................ 72 E 1 Decreased coo ling loads. Zone 1 Miami, FL ................................ ................................ .. 73 E 2 Decreased cooling l oads. Zone 2 Gainesville, FL ................................ .......................... 73 E 3 Decreased cooli ng loads. Zone 3 Atlanta, GA ................................ ............................... 73 E 4 Decreased cooli ng loads. Zone 4 Seattle, WA ................................ ............................... 74 E 5 Decreased cooli ng loads. Zone 5 C hicago, IL ................................ ................................ 74 E 6 Decreased cool ing loads. Zone 6 Helena, MT ................................ ................................ 74 E 7 Decr eased cooling loads. Minot, ND ................................ ................................ ................ 75 E 8 Decreased co oling loads. Zone 8 Nome, AK ................................ ................................ 75 F 1 Annual Ener gy Savings. Zone 1 Miami, FL ................................ ................................ ... 76 F 2 Annual Energy Sav ings. Zone 2 Gainesville, FL ................................ ........................... 76 F 3 Annual Energy Savings. Zone 3 Atlanta, GA ................................ ................................ 76 F 4 Annual Energy Savings. Zone 4 Seattle, WA ................................ ................................ 77 F 5 Annual Energy Savings. Zone 5 Chicago, IL ................................ ................................ 77 F 6 Annual Energ y Savings. Zone 6 Helena, MT ................................ ................................ 77 F 7 Annual Ener gy Savings. Zone 7 Minot, ND ................................ ................................ .. 78 F 8 Annual Ene rgy Savings. Zone 8 Nome, AK ................................ ................................ .. 78

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9 LIST OF FIGURES Figure page 2 1 Examples of mass walls ................................ ................................ ................................ ..... 18 2 2 Example of metal building wall ................................ ................................ ......................... 19 2 3 Example of steel framed wall ................................ ................................ ............................ 20 2 4 Example of wood framed wall ................................ ................................ ........................... 20 3 1 Methodology flowchart. ................................ ................................ ................................ ..... 33 3 2 Code minimum exterior wall assembly ................................ ................................ ............. 35 3 3 Rin ker Hall exterior wall assembly ................................ ................................ .................... 36 3 4 ASHRAE Map of US climate zones ................................ ................................ .................. 37 4 1 ThermaChannel. Image from ThermaChannel, Inc ................................ .......................... 40 4 2 ThermaChanne l cross section with dimensions ................................ ................................ 40 4 3 ThermaChannel cross section with dimensions. ................................ ................................ 41 4 4 Slit Web Stud. Image from ORNL. ................................ ................................ .................. 42 4 5 ThermaChanne l cross section with dimensions ................................ ................................ 43 4 6 Aerogel strips being applied t o met al stud. Image from ThermaBlok .............................. 44 4 7 ThermaChanne l cross section with dimensions ................................ ................................ 45 4 8 Dimpled flange stud ................................ ................................ ................................ ........... 46 4 9 Di mpled flange stud wall assembly ................................ ................................ ................... 46 4 10 Thermal ce ramic coated stud wall assembly ................................ ................................ ..... 48 4 11 R value calculation results comparison. ................................ ................................ ............ 49 4 12 U factor calculation results comparison. ................................ ................................ ........... 50 4 13 2D heat fl ow analysis. Code minimum wall ................................ ................................ ..... 51 4 14 Decreased energy lo ads for each wall assembly type ................................ ........................ 53 4 15 Decreased energy co sts for each wall assembly type ................................ ........................ 54

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10 4 16 Projected breakeven years. ................................ ................................ ................................ 56 C 1 2D heat f low analysis. Rinker Hall wall ................................ ................................ ........... 66 C 2 2D heat flow ana lysis. Ridged flange stud wall ................................ ................................ 67 C 3 2D heat flo w analysis. Slit web stud wall ................................ ................................ ......... 67 C 4 2D heat flow anal ysis. Dimpled flange stud wall ................................ ............................. 68 C 5 2D heat flow analysis. Aerogel strip stud wall. ................................ ................................ 68 C 6 2D heat flow analysis. Ceramic coated stu d wall ................................ ............................. 69

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11 A bstract of T hesis P resented to the G raduate S chool of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science in Building Construction EVALUATION OF ALTERNATIVE METAL STUD FRAMING TO REDUCE THERMAL BRIDGING IN EXTERIOR WALLS By B. Kevin Bennett August 2011 Chair: Ravi Srinivasan Major: Building Construction Thermal bridging is a transfer of energy through the most thermally conductive material in an otherwise well insulated assembly. In the case of exterior building walls constructed with metal studs, the steel framin g is the path of least resistance of thermal energy within the system. As a consequence, the thermal performance of exterior wall system s is degraded and higher energy costs are incurred. The purpose of this thesis is to evaluate several innovative mater i als and products that appear capable of significantly reducing the thermal bridging effect experienced in exterior metal stud framing. This research evaluates and compares these products, based upon their thermal performance and associated initial and li fe cycle costs. The heat conduction properties of each of the alternative products were determined as components within Code minimum compliant wall system assemblies using two dimensional heat transfer analysis software T he U factors of each of the wall asse mblies were then entered into building energy simulation model s based upon the design of Rinker Hall at the University of Florida to project annual energy savings based upon the anticipated heating and cooling loads resulting from exterior wall heat c onduction

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12 To further understand how climatic variances could affect thermal performance, simulations were created for each of the energy mod els in each of eight US climate zones. The national average for the cost of electricity per unit in kilowatt hours was then applied to the energy loads determined for each model. Additionally, cost estimates were prepared for each of the wall type assemblies to understand the initial cost implications associated with each of the alternative products. The energy load differentials were then applied to life cycle cost analyses to determine the overall cost effectiveness of each of the alternative produ cts over an extended period of 3 0 years. This process took initial costs, pr ojected energy savings, discount rate s and energy inflation rate s into account to determine which of the products, if any, would be recommended by this study.

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13 CHAPTER 1 INTRODUCTION Background In recent years, the threats posed by escalating energy prices, dwindling natural resources and the pos sibility of dramatic global climate change has increasingly focused attention on the level of energy expended on the operation and maintenance of commercial build ings. A study conducted in 2010 by the U.S. Department of Energy (DOE) estimated that commerc ial and residential buildings combined accounted for nearly 40% of all energy consumption in the U.S. in 2008 ( DOE 2010 ). The US National Science & Technology Council (NSTC) projects that worldwide energy consumption by buildings will be greater than the transportation and industrial sectors combined by 2025 (NSTC 2008). Mitigating heat transfer through the exterior building envelope, which serves as the physical barrier between the exterior and interior environment, is a critical component in increasing the energy efficiency of buildings. The traditional soluti on has been to fill the cavity terial (such as fiberglass insulation) as possible. Unfortunately, this approach is limite d due to the placement of other highly conductive materials within the walls, such as steel studs, that create thermal bridging. Thermal bridging is a transfer of energy through the most thermally conductiv e material in an otherwise well insulated assembly In the case of exterior building walls constructed with metal studs, the steel framing is the path of least resistance for thermal energy within the system. As a consequence, the thermal performance of the exterior wall system is degraded and higher en ergy costs are incurred The degradation in the energy performance of exterior wall systems

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14 due to metal stud thermal bridging is estimated to be as high as 55% (Kosny and Desjarlais 2001 ) Statement of Purpose The purp ose of this research was to evaluat e several innovative materials and products that appear ed capable of significantly reducing the thermal bridging effect experienced in exterior metal stud framing. These products were evaluated and compared based upon their thermal performance and associa ted initial and life cycle costs as components within an exterior wall system. Ultimat ely, the goal of the research was to determine the most energy efficient and cost effective method of constructing exterior wall systems using steel framing. Objective s The objective of this research was to determine the ability of alternative metal framing products designed to increa se the energy performance of exterior wall system assemblies Using the thermal requirements of a Code minimum wall as a basis of evaluation, this research followed the American Society of Heating, Refrigeration and Air Conditioning Engineers ( ASHRAE ) prescriptive methods for determining building envelope U factors These ASHRAE prescriptive procedures were used to det ermine the U factors for exterior wall assemblies that incorporated each of the alternative metal framing products. Additionally two dimensional heat flow analysis software was utilized to achieve more refined and accurate U factors. Following the determ ination of U factors, using the Code minimum wall assembly as a baseline for evaluation, b uilding energy simulation computer models were developed for each of wall system scenarios for each of the eight climate zones in the US The primary building energy u se simulation program used in this research was Equest 3.64 which was developed by the Lawrence B erkley National Laboratory (LBNL ) on behalf of the DOE

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15 For cost perspective and econo mic viability, analyses were conducted to determine the initial constr uction cost increases expected from each of the products. Coupled with the energy performance data, this information was used to develop life cycle costs analyses (LCCA ) for each alternative Ultimately, the objective of the LCC A as to whether or not the alternative metal framing products being considered in this research could provide dividends in the future and how soon.

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16 CHAPTER 2 LITERATURE REVIEW The Building Envelope The United States Code of Federal Regulations defines the building envelope elements of a building that enclose conditioned spaces through which thermal energy may be transferred to or from (10 C F R § 434 201 2010). ASHRAE defines the and ou 2009 ). In essence, the bu ilding envelope helps protect a building and occupants f rom the outside environment. The building envelope keeps rain and other elements out and helps to maintain comfortable environmental conditions for the people who live in, work in and visit building s In reference to energy function and performance, a building envelope must serve three broad functions in energy efficient buildings (Straub & Burnett 2005): Support the efforts of mechanical systems to resist the transfer of heat into or out of a Control the flow of matter and energy into and out of a building, including: r ain, air, h eat and vapor Finish to ensure that human comfort needs are met A building envelope is made up of many comp lex, multi layered assembli es, including: roofs, above and below grade walls, elevated slabs and slabs on grade, fenestration and doors. Although the integrities of all the assemblies within a well designed building envelope are critical components in creating an energy efficient building, exterior walls are of particular importance Typically, exterior walls comprise the greatest area of envelope, have the greatest complexity and are the most likely source of intrusion by air and water.

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17 Exterior Wall Systems Designers of exterior walls must balance a daunting multitude of concerns in their efforts ASHRAE describes the ideal envelope assembly as one that achieve a thermal balance for 2009). In addition to decisions which shape the parameters within which exterior wall systems are designed, including aesthetics, function, durabil ity maintainability, fire rating, acoustics a nd budget, c onsiderations that must be contemplated by designers regarding high performing, energy efficient buildings include: Air infiltration Moisture protection Thermal performance Wall types Wall type decisions are heavily influenced simply by the int ended function of the facility being designed. For example, industrial facilities are often designed with initial economy in mind rather than aesthetics and pre engineered metal buildings designs are selected for this reason Typically, although not alwa ys the case, the exterior walls of pre engineered metal buildings are clad in sheet metal Most commonly in US residential construction, exterior wall assemblies are composed of wood stud framing with an exterior sheathing layer, gypsum board on the inter ior and fiberglass insulation infilling the cavity spaces between the studs. Metal stud framing is generally more common in commercial construction in the US. A S HRAE Handbook Fundamentals classifies four types of above grade exterior wall typ es as follows (ASHREA 2009 ): Mass walls Metal building walls Steel framed walls Wood framed walls and others

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18 M ass walls are walls that are constructed with solid heavy material such concrete, masonry, stone or earth with a heat capacity exceeding 7 ( BTU/ft 2 ) per ASHRAE 90.1 standards. ASHRAE further ind icates that wall s constructed with lightweight materials with a unit weight not greater than 120 ( lbs/ft 3 ) must have a heat capacity of greater than 5 ( BTU/ft 3 F ) in order to qualify as a mass wall. Figure 2 1. Examples of mass walls. Mass walls have high thermal mass, meaning that they have the capacity to store heat energy which allows for passive cooling and heating of buildings. In a passive heating sc enario, the thermal mass of a mass wall absorbs and stores heat energy from sunlight during the day. building. For passive cooling scenarios, the thermal mass of a mass wall is capable of absorbing the internal heat of a building and dissipating the heat energy to the exterior of the building at night. Metal Building Wall s are associated with pre fa bricated metal buildings and typically have exterior metal panel s attached directly to horizontal metal supports called girts that span Concrete Conc rete Block

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19 structural support column s. I nsu lation is typically installed between the interior face of the metal pan els and the horizontal steel girls. Figure 2 2. Example of metal building wall. Steel Framed wall s are constructed with metal stud framing members This is a very common construction type in US commercial, institutional and some residential buildings because non combustible assemblies are usually required by building codes f or many of these classes of construction A myriad of benefits has increased the popularity of metal stud framing in the US construction industry. Its low wei ght and high strength relative to wood framing are important factors; however, ease and speed of erection are the most significant positive attribute s of metal stud framing. Metal studs have a particularly significant disadvantage in relation to wood fra ming: steel is approximately 357 times more thermally conductive than wood. Simply put, this means that steel framing members within exterior wall systems are the primary conduit in which heat is ace. Based upon studies conducted by the Exterior Meta l Panel Steel Girt Insulation Steel Column

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20 Oak Ridge National Laboratory ( ORNL ) steel studs decrease the thermal resistance of a wall assembly by as much as 55% ( K osny and Desjarlais 2001). Figure 2 3. Example of steel framed wall. Wood f ramed walls are defined by ASHRAE as walls constructed with wood framing or any type of wall construction that does not qualify as a mass, metal building or steel framed wall In US residential construction, wood framing is the predominant building technique due to its economy Typically, gypsum board is attached to the interior face of 2x4 wood studs, exterior sheathing materials are attached to the outside face of the studs and the cavity space created between the interior and exterior sheathing materials is filled with insulating materials. Figure 2 4. Example of wood framed wall. Gypsum Board Metal Studs Insulation Exterior Sheathing Stucco System Gypsum Board Wood Studs Insulation Exterior Sheathing Stucco System

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21 Ulti mately, regardless of type, the ability of a n exterior wall to either conduct or resist the transfer of heat energy is a critical concern when des igning energy efficient building s This characteristic is a primary determining factor in the sizing and usage of HVAC equipment and, as a consequence, the levels of energy necessary to condition the interior space of a building. H eat Transfer The exchange of heat from one material to another is known as heat transfer. There are three forms of heat transfer that affect the energy performance of a building envelope: conduction, convection and radiation. Conduction is an exchange of thermal energy that occurs when materials are in direct contact with one another. Convection occurs when the flow of gases or f luids carries thermal energy from one material to another. R adiation is the transfer of thermal energy through transparent mediums or even in the absence of any medium at all (e.g. a vacuum ) via electromagnetic waves. The primary means of decreasing heat transfer in the opaque portions of building envel opes is by limiting conduction. This is typically achieved by the incorporation of thermal insulat ing materials with in the cavity spaces of envelope assemblies. The ability of a material to resist the tra nsfer of heat through conduction is known as its th ermal resistivity. The unit of measure for the thermal resistivity of a material is expressed as ( hr ft 2 F /Btu). The reciprocal of thermal resistivity is known as thermal conductivity and is the pro perty of a materia l to conduct heat. T he unit of measure for thermal conductivity is expressed i s as ( Btu/ hr ft 2 F ). In the US construction industry, t he thermal c onductivity or resistivity of a material is typically rated in terms of their R value or it s reciprocal U value. These values take into account the actual thickness es of material s Materials with higher R values are thermally superior to those with lower R values. Materials with lower U values p erform better thermally to those with higher U values.

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22 While R values and U values are associated wi th single specific materials U fa ctors were developed t o provide insight into how assemblies of materials perform thermally as integrated unit s ASHRAE de fines a U (ASHRAE 2009) U factors are often associated with wi ndow units or building envelope assemblies such as walls or roofs This nomenclature provides guidance to designers and const ructors as to the energy efficiency of building assemblies Beyond thermal conductivity and resistivity, there are other thermo physical p roperties of building materials within an opaque envelope system that determine the ir ability to transfer or resist th e flow of heat energy Thes e properties include: density, heat capacity, and surface characteris tics wi th respect to radiation ( emi ssivity and reflectivity ) The density of a material is defined as its mass per unit volume. The unit for density is pounds per cubic foot (lbs/ft 3 ). is a factor in the determination of its heat capacity. H eat capacity is e added to one square unit of surface ( ASHRAE 2009). Heat capacity is expres sed in terms of British thermal units per square foot per degree Fahrenheit ( Btu /f t 2 F). The heat capacity of a material is significant in determining the quantity of thermal mass in performance factor. For example, the degree of ther mal mass differentiates whether a wall can be classified as a mass wall per ASHRAE 90.1 standards.

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23 Surface e missivity and reflectivity are not actually material properties. Rather they are attributes of a material s surface. Emissivity describes th e abil ity of a surface to emit heat by radiation Conversely, reflect ivity is the reciprocal of emissivity and describes the ability of a surface to reflect solar radiation. Reflectivity and emissivity are dimensionless properties and range in value on a scal e from 0 to 1. A material that is highly reflective would have an emissivity coefficient closer to 1 ; a material that is highly reflective would have an emissivity coefficient closer to 0. For example asphalt has an emissivity coefficient of 0.93; polished gold has an emissivity of 0.025. No material can have an emissivity of coefficient of either 0 or 1 as these values are theoretical extremes. U Factor Determination The most basic met hod of calcula ting U factors of opaque exterior wall assemblies is the clear wall method. The clear wall area is the portion of an exterior wall that is uncluttered by architectural details such as framing and material intersections such as concrete balco nies. This type of analysis only takes into account the exterior sheathing, stud cavity and insulation and interior sheathing materials. Essentially it disregards the thermal effects of other significant construction features, including steel framing. The degradation to thermal performance due to the inclusion of metal studs is known as the framing effect. Research by ORNL estimates the decrease in exterior wall assembly U factors to be 30% to 50% with clear wall calculations versus those taking the me tal stud framing i nto account (Kosny and Desjarlais 2001).

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24 The impact of inclusion of metal studs on an exterior wall assembly is illustrated in Figure 2 5 Both wall assemblies depicted 13 fiberglass ins Both wall assemblies are modeled to assess thermal performance in two dimensional heat flow analysis software (THERM 6.3). T he upper wall assembly is modeled without studs a nd the lower is model ed with 3 5/8 out metal studs is determined to have a U factor of 0.0365. The inclusion of metal studs in the lower wall degrades the thermal performance of the wall to a U factor of 0.0625 or 41.6%. Figure 2 5 U factor degradation due to metal studs in wall assembly. Table 5 H of the 2009 ASHRAE Handbook Fundamentals establishes s eve ral methods for calculating U factor s of various building assemblies The methods for above grade walls include: Parallel Flow Method Isothermal Planes Method Modified Zone Method 2D Calculation Method Testing U factor = 0.0365 without metal studs U fac tor = 0.0625 with metal studs

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25 Parallel Flow Method The parallel flow method is slightly more advanced than the clear method in that it takes the framing effect into account by calculating a weighted average of clear wall areas and framed wall areas. In this method, U factor s of clear wall assembly area s and U factor s of framed wall assembly area s are multiplied by thei r respective percentages of wall area and summed The parallel flow method is acceptable in Table 5 H of the 2009 ASHRAE Handbook Fundamentals for wood framed walls; however it is not approved for calculating U factors of steel framed walls. Although th e parallel path method is considered to be more accurate than the clear wall approach, it typically underestimates the actual area of framing in exterior wall system s once corners, intersection and opening s are taken into account The other significant sh ortcoming of this method is that it treats framing member s as if they were solid block of material. This is not quite so problematic in the case of wood framing. However, a problem arises with this approach when the framing is C shaped metal studs as these members are not solid blocks. Isothermal Planes Method The isothermal planes method is slightly more sophisticated than the parallel flow method. In this approach, only the materials between the interior and exterior sheathing are modified by their respective percentages of wal l area. Although the isothermal planes method is acceptable for calculating U factors of above grade steel framed walls under ASHRAE Standard 90.1, the standard requires the application of adjust ment factors per Table A9.2 B to the insulating layer Modified Zone Method The modified z one method was de veloped by ORNL to specifically assist in the thermal evaluation of metal framed assemblies. ORNL researchers have demonstrated the modified zone

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26 method to be the most reliable prescriptive calcula tion method based upon comparative laboratory test results and finite element analysis. Similarly to the parallel flow method, the modified zone method performs calculations on both the framed and non framed areas of an assembly then combines the results using a weighted average formula. This approach involves d ividing an assembly into zones and increasing the width of the stud flange to a value equal to the ratio of the thermal resistivity of the finish material to the thermal resistivity of the cavity insulation. The application of the modified zone method is only applicable to assemblies with C shaped metal framing elements. 2D Heat Flow Analysis Two dimensional heat flow analysis is a complex mathematical analysis used to determine U factor s of complex building assemblies. Unlike one dimensional calculatio n methods, this more advanced method does not assume that heat flows in a direct line from one side of a boundary to the other. This process takes into account lateral conductive and convective heat flow to provide U factor results for the assemblies in a steady state. The approac h subdivides the elements of assemblies into many smaller pieces and calculates the thermal relationship between each. Two dimensional heat flow analysis is based upon electric circuit theory and is typically conducted with the assistance of computer simulation programs One such program (THERM) was developed by the Lawrence Berkley National Laboratory (LBNL) and is based upon the finite element method. The deficiency found in most two dimensional heat flow analysis programs is that they are only capable of analyzing wall assemblies as a series of one dimensional layers. The problem in this approach is that the effects of thermal bridges are not accounted for i n the transient resp onse of assemblies (Enermodal 2001).

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27 3D Heat Flow Analysis In the next step in the evolution of heat flow analysis, ORNL developed finite difference computer code which was incorporated into a program known as Heating 7.2. Although not created specifically for evaluating building envelopes, this program is able to map heat flows through wall assemblies to solve steady state and transient heat conduction problems in three dimensional Cartesian coordinates. Despite the advancements that three dimensional heat flow analysis program s provide the significant drawback experienced by users is the long series of response factors that sometimes must be input. For massive walls, 60 to as many as 150 numbers, multiplied by 3 must be input accompanied by the troublesome modification of the program sour ce code to enable this type of wall data input (Kosny and Kossecka 2001) Equivalent Wall Model The development of a simplified approach to determining wall assembly U factors is known as the equivalent wall model (Kossecka and Ko sny 1996). Developed by ORNL practitioners of this approach are able create theoretical homogeneous wall s with the identical material properties (conductivity, resistivity, density, heat capacity ) of multi layer wall s that have already been laboratory tested and modeled in three dimensional software by ORNL researchers. In this manner, the transient conditions and dynamic response of wall s under design are considered equivalent to actual previously tested and catalogued wall system assemblies Testing The most accurate U factor determination method is actual laboratory testing. ASHRAE Standard 90.1 allows for three types of testing procedures: Guarded Hot Plate (ASTM C 177) Heat Flow Meter (ASTM C 518) Hot Box Apparatus (C 1363)

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28 Figure 2 6. Guarded hot box testing apparatus. Image from Butler Manufacturing. Under these procedures, sample wall section s and place d into testing units. Heat flow is determined by measuring the energy required to maintain the steady state temperature on th e warm side of the wall. Although these testing methods provide the most reliable and accurate data, high costs and lengthy durations pose a significant disadvantage. Energy Analysis Building energy use simulation s are computer models created to predict annual energy consumption. Building energy models should include all the necessary operating and design parameters that affect the energy consumption levels of a facility. Such parameters include the thermal performance abilities of envelope assemblies and components ; electrical requirements of lighti ng, receptacles, HVAC equipment; building and space functions and occupancy counts. Simulation models are able to account for the location and orientation of a building and utilize histo ric weather data. All of this information is correlated and interpreted by

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29 advance. Economic Analysis The US General Accountability Office (GAO) def ines Life C he overall estimated cost for a particular program alternative over the time period corresponding to the life of the program, including direct and indirect initial costs plus any periodic or continuing costs for operation and maintenan a financial method for determining the total costs associated with owning and operating a facility over a period of time. cycle benefits of one al ternative versus another in planning and design stages. Although each of the below are not necessarily needed for every LCCA, the financial components that typically must be determined in the creation of LCCA are as follows: i nitial expenses f uture expenses r esidual value s tudy period r eal discount rate c onstant dollars and p resent value Initial & Future Expenses The first factor s in LCCA creation are related to the costs associated with a facility prior to and following occupation. The expenses incurred prior t o occupation are referred to as initial expenses or initial investment costs. Initial expenses are generally associated with the following cost categories: l and acquisition s ite investigation d esign services c onstruction c onstruction management e qui pment & technology and c ontingency The expenses that are projected to be incurred after occupancy has commenced are as referred to as future expenses and are generally associated with the following cost categories: Operational costs: Expenses incurred in the ongoing operation of a facility Includes utility (e.g. electricity, water, gas steam), waste removal, custodial, grounds, insurance and lease expenses.

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30 Maintenance and repair costs: These expenses can be eit her scheduled or unscheduled and are associated with the upkeep of a facility. An example of a scheduled cost would be the replacement of HVAC air filters on a regular interval. An example of an unscheduled expense would be the unexpected repair o f a HVA C unit due to malfunctions or breakdowns. Replacement costs are the expenses associated with the scheduled replacement of building components or systems An example of a scheduled expense would be the replacement of an HVAC unit at the end of its expected lifetime. Residual Value Residual or salvage value is the value of a facility or facility component at the end of its useful life. Residual values can be positive or negative. A positive residual value indicates an expense is expected to be incurred. An example of positive residual value would be the cost incurred to an owner for the demolition of a facility. A negative residual value indicates revenue is expected to be realized. An example of negative residual value would be the scrap value of a bu Study Period The study period is the length of time that an LCCA is designed to evaluate. In the evaluation of a building or building component, study periods typically span a 20 to 40 year period. Although a study period can cover the entire expected lifespan of a facility, it is not necessary to use this approach. Real Discount Rate The discount or capitalization rate is a multiplier used to convert the future anticipated returns from an investment to a pre sent value. The discount rate allows an investor to assess the time value of money associated an investment by converting future values to present values The the next best alternative. Discount rates can be either nominal discount rates or real discount rates ; t he form er factor s in the rate of inflation while the latter does not.

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31 Constant Do llars Constant dollars is a measurement of comparative purchasing power associated with a reference year without factoring in inflation rates. This provides building owners the ability to assess alternatives that may have differing lifespans. For example, one HVAC unit might have an expected life of 20 years while another might be expected to last only 15 years. The need to estimate the replacement cost associated with the 15 year unit while factoring in increases in labor and material costs is eliminated. The initial and future costs of installing a new HVAC unit are the same; the time value of money is instead accounted for by the real discount rate in Present Value P resent value is defined by the GAO he worth of a future stream of returns or costs in terms of money paid immediately (or at some designated da te) value is that a dollar available today has greater worth than a dollar at a future date because the former invested could be invested and earning interest. To calculate present value, the discount rate and incurred date of the expense are used. Present values of initial expenses require no additional calculations to determine their value because present value and initial costs are equal at that time. Present values of future expenses are time dependent, however. Future costs are either recurring costs or one time costs. Recurring costs are costs that are anticipated to occur in regular annual intervals. One time costs are typically associated with replacement costs and do not occur on an annual basis. The form ula to determine the present value of one time costs is as follows:

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32 = Present value = Amount of one time cost = Discount rate = Time in years The formula to determine the present value of recurring c osts is as follows: = Present value = Amount of one time cost = Discount rate = Time in years

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33 C HAPTER 3 RESEARCH METHODOLOGY Overview The research methodology of this report consists of four modules: (1) Identification of alternative framing materials, (2) Determination of the U factors of a baseline Code compliant wall assembly and wall assemblies with the alternative framing materials incorporated, (3) Development of building ener gy models, and (4) Cost analyses to determine the most effective long term soluti on. In order to assess how varying climate conditions can impact the thermal performance of a b uilding each solution is modeled in each of the eight US climate zones. Figure 3 1. Methodology flowchart. Identify Alternative Framing Solutions Identify Material Properties Determine U Factors Using 1D Parallel Flow Method Determine U Factors Using 1D Isothermal Planes Method Determine U Factors Using 2D Finite Element Method Develop Wall Sections & Details Evaluate and Compare Findings Develop Benchmark Energy Model Develop Building Energy Models for Each Alternative for Each of the (8) U.S. Climatic Zones Con ductance Structural Fire resistance Costs MATERIALS 1 1 Evaluate and Compare Building Energy Consumption Levels Determine Cost Data Develop Life Cycle Cost Analyses Present Optimal Solution Conductance Structural Fire resistance Costs U FACTORS ENERGY ANALYSES COST ANALYSES 1 2 3 4

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34 Step 1: Identification of Alternative Materials Five alternative metal framing options designed to improve building energy performance were evaluated These alternative framing products were selected for study because of their potential to decrease the thermal bridging effect in metal framing components. Three of the solutions evaluated attempt to achieve this goal by altering the configuration/design of the metal stud; the other two solutions attempt to decrease thermal bridging by the application of topical materials with low thermal conductivity. Step 2 : Material Properties In order to evaluate the impact on thermal performance of the alternative materials, the thermo physica l properties of the each of these materials had to be identified. This research utilized manufacturer literature for this informa tion. However becau se the energy performance of exterior wall system s are dependent upon the interrelated thermal dynamics of all the materials within the system s the thermo physical properties of all the components within each assembly had to be identi fied, as well. This research utilized for material properties that was available from high ly regarded sources such as AS H RAE, DOE and the Natio nal Fenestration Rating Council (NFRC). Using the ASHRAE approved methods defined in Tabl e 5 H of the ASHRAE Han dbook Fundamentals (parallel flow, isothermal planes and two dimensional heat flow analysis ), the U factors for a Code mi nimum exterior wall assembly, each of the alternative wall assemblies and the Rinker Hall w all assembly were determined per the requi rements of each method. In this study, a Code minimum wall assembly is composed of an interior sheathing layer of d thermal insulation in the cavity spaces. Per the

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35 requirements of Table 5.5 of ASHRAE Standard 90.1 for above grade steel framed walls, the R value of the cavity insulation material was established at the minimum value of R 13. Figure 3 2 Code minimu m exterior wall assembly. Rinker Hall at the University of Florida was selected as a model building to evaluate the alternative products and the expected improvements to energy performance. A review of the walls. The interior sheathing layers included 2x2 wood blocking attached directly to the inside sheathing board, water resistant membrane and an aluminum panel rain screen system. The cavity insulation material was rated as R 21.

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36 Figure 3 3 Rinker Hall exterior wall assembly Two dimensional heat flow analysi s was performed by modeling the Code minimum and Rinker Hall walls in THERM 6.3 to determine the U factor s for each assembly. Additionally, wall sections that modified the Code minimum wall by incorporating the a lternative products were modeled in THERM 6.3 to determine their respective U factors. Step 3: Energy Analyses Following the determination of U factors, using the design of Rinker Hall as a base building model building energy computer models were develo ped for each of wall system scenarios The building energy use simulation program used in this research was Equest 3.64 which was developed by the Lawrence Berkley National Laborato ry (LBLN) on behalf of the DOE. The purpose of the energy analyses was to determine building heating and cooling loads resulting specifically from wall conduction.

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37 To further refin e the energy model analyses, energy models were developed for one city in each of the eight ASHRAE define d climatic z ones in the US Figure 3 4 ASHRAE Map of US climate z ones. The locations selected are as follows: Zone 1: Miami, FL Zone 2: Gainesville, FL Zone 3: Atlanta, GA Zone 4: Seattle, WA Zone 5: Chicago, IL Zone 6: Helena, MT Zone 7: Minot, ND Zone 8: Nome, AK

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38 Step 4: Cost Analyses In order to calculate life cycle costs for each of the exterior wall assemblies, i t was first necessary t o determine the annual energy cost savings anticipated from e ach of the alternative products. To accomplish this, the national average unit f or a kilowatt of electrical cost was applied to the energy savings projected for each energy model based upon the improvements to heating and cooling loads from specifically related to exterior wall conduction. Next, it was necessary to determine the addit ional construction costs associated with the substitution of each of the alternative products into a Code minimum wall. Unit cost estimates for the Code minimum, Rinker Hall and alternative wall assemblies were developed based upon information provided by material manufac turers and RS Means Cost Data and applied to quantity take offs of materials needed for the Rinker exterior wall system. Finally, once the cost savings expected from increased energy performances and initial cost increases associated with construction were established, this information was used to generate The LCC A rates, general inflation rates and energy inflation rates to provide insight as to whether or not an investment being considered today wall systems could provide dividends in the future and how soon.

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39 CHAPTER 4 RESULTS AND ANALYSE S O verview The results and a nalyse s portion of this report is divi ded into four sections. The first section describes the alternative framing products that were reviewed in this research. The second section details the U factors determinations based upon the approved calculation methods specified in ASHRAE Handbook F undamentals ( Table 5 H ) for these alternative products as substitute components incorporated into Code minimum exterior wall assembli es The third section details the building energy analyses performed incorporating the wall assembly U factors calculated in Step 2 in energy models of Rinker Hall in each of the eight US climatic zones The fourth section examines the estimated additional initial costs and projected energy savings for each scenario in life cycle cost analyses. S ection One: Alter native Metal Framing Solutions This research identified and reviewed several alternative products that appeared likely to have some degree of ability in decreasing thermal bridging in metal framing. After reviewing options currently available, the followi ng five candidates were selected for this study: Ridged flange studs Slit web studs Dimpled flange stud Aerogel strips Thermal ceramic coated studs The candidate products were evaluated based the following criteria: Thermal performance Structural performance Fire rating performance Cost data

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40 Ridged Flanged Studs Ridged flange studs approach decreasing thermal bridging by altering the configuration of the stud so that contact between the stud flanges and interior/exterior sheathing is minimized. Th e flanges of the stud are bent to form parallel ridges so that the middle flange areas are held away from sheathing materials Ridged flange studs were developed by Portland architect LeRoy Flanders and patented and marketed under the bra nd name ThermaChannel. Although a US patent for ThermaChannel was issued in 1997, a ThermaChannel representative indicated that the product has never been commercially produce d nor installed in any building (G. Seeberger, ThermaChannel, personal communica tion, June 16, 2011). Figure 4 1. ThermaChannel. Image from ThermaChannel, Inc. Figure 4 2. ThermaChannel cross section with d imensions.

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41 Thermal performance. ThermaChannel was tested by the ORNL and results indicated that the insulation efficiency of exterior wall s constructed with this type of stud had a minimum 10 % in crease ( Strohl 1995). Structural performance. Structurally, the inwardly bent flanges may cause this type of stud to have a decreased ability to withstand closer to the centerline of the stud. However, this decrease may be offset by the additional strength that would be created by the corrugation effect created by the bent flanges. An estimated decrease in the structu ral ability of ridged flange studs is not available; however th e diminishment appears to be low. Fi gure 4 3. ThermaChannel cross section with dimensions. Fire rating performance. From a combustibility perspective, th e use of this type of stud does not create any additional concerns as it is composed of steel like a conventional metal stud. Cost data. Due to the bent configuration, ridged flanged studs cost approximately 15% more than conventional C shaped studs. Because of the added bends, more steel material is needed to manufacture these types of studs. Based 2011 RS Means cost data, conventional C Ridged Flange Studs R 13 Insulation Grace Ice & Water Shield

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42 shaped 6 inch 16 gage metal framing with has an assumed cost of $3.27 per square foot of framed exterior wall area (labor, material and OH&P) Based upon this information the assumed cost for ridged flanged studs with the same specif ications is approximately $ 3.76 per square foot of framed exterior wall area. Slit Web Studs The manufacturers of slit web studs approached break ing the metal framing thermal bridge by modify ing the web of the stud. Rather than having a sol id web similar to conventional C shaped stud s slit web studs have thin openings or slots cut into the web of the stud These opening s long. The purpose of the openings is to break t he thermal connection between the interior flange of the stud and the exterior flange Figure 4 4 Slit Web Stud. Image from ORNL. Thermal performance. Hot box testing by ORNL determined that a minimum 10 % increase in thermal performance could be realized by the substitution of slit web studs in lieu of

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43 convention studs when incorporated in to a Code minimum exterior wall assembly. Research by ORN L conducted for the American Iron & Steel Institute estimated that 2. 0 to 2.6 additional R value could be gained by the substitution of triangular cutout studs ( E lhajj 2006). Structural performance. The openings in t he web of the studs may cause some structural concerns. A study conducted by the U.S. Steel Laboratory foun d an 8 10% decrease in lateral load strength in walls constructed with 18 gauge slit web studs (McDermott 1975). Fire rating performance. From a combustibility perspective, the use of this type of stud would not create any additional concerns as it is co mposed of steel like a conventional metal stud. Figure 4 5 ThermaChannel cross section with dimensions. Cost data. A study conducted for the American Iron & Steel Institute indicated that the material cost increases for the manufacture and in stallation of slit web studs were no t significantly more than conventional studs ( E lhajj 2006). Based 2011 RS Means cost data, c onventional C shaped 6 inch 16 on center has an assumed cost of $3.27 per square foot of framed exterior wall area (labor, material and OH&P). Slit Web Studs R 13 Insulation Grace Ice & Water Shield

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44 Based upon an estimated cost increase of 5% t he unit cost for a wal l constructed simil arly with slit web studs is assumed to be $3.43 Aerogel Strips Aerogel was developed by NASA and is considered to have the lowest bulk density of any known porous solid. According to manufacturer l iterature from ThermaBlo k these strip s are designed to be adhered to the interior face of metal studs on the backside of gypsum wallboard. The material is intended to create a thermal break between the metal framing and interior gypsum board. Figure 4 6 Aerogel strips being applied to me tal s tud. Image from ThermaBlok. Thermal performance. ThermaBlok product literature indicates that their aerogel strip an R value of 10.3 per inch. Hot box testing conducted by the Oak Ridge National Laboratory found that internal surface temperatures between the metal stud and the center of a metal stud wall assembly cavity wer e reduced by 5 F (Kosny et al 2007). Structural performance. The addition of Aerogel strips between the inside stud flang e and interior gypsum board would not compromise structural integrity. Fire rating performance. Due to its high degree of thermal resistance, Aerogel products do not raise any combustibility concerns, including off gassing. Manufacturer literature from

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45 ThermaBlok indicates that the products have The application of thi not present any fire rating issues. Figure 4 7 ThermaChannel cross section with dimensions. Cost data. Although Aerogel provides significant thermal insulating attributes, the limiting factor is its relatively high cost (Kosny and Yarbrough 2007). According to a ThermaBlok representative the mat erial is approximately $1.00 per lin strips (Steve Hibbins, personal communication, June 16, 2011). This unit price translates to nearly $30,000 of additional costs when applied to the estimated 30,000 linear feet of exterior metal studs necessary for Rinker Hall. Therefore, the square foot unit cost increase to apply ThermaBlok aerogel strips relative to the 13,642 square feet of exterior wall m etal framing is $2.16. Dimpled Flange Studs Similarly to ridged flange studs, the concept behind dimpled flange studs is to decrease surface contact between the metal framing and interior/exterior she athing layers. Raised dimples Aerogel Strip Metal Stud R 13 Insulation Grace Ice & Water Shield

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46 on the flanges on the stud reduce serve this purpose and contact surf ace are a is reduced by approximately 67 % Figure 4 8 Dimpled flange s tud. Thermal performance. The National Association of Home Builders Research Center estimated that dimpled flange studs could improve the R value of an exterior wall assembly by approximately 0.61 ( E lhajj 2006) Structural performance. No information was available to determine whether or not the flange dimples decreased the structural ability of a metal stud. Fire rating performance. From a combustibility perspective, the use of this type of stud does not create any additional concerns as it is composed of steel like a conventional metal stud. Figure 4 9 Dimpled f la nge stud wall a ssembly. Dimpled Flange Studs R 13 Insulation Gra ce Ice & Water Shield

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47 Cost data. A study conducted by the National Association of Home Builders Research Center indicated that the material cost increases for the manufacture and installation of dimpled flange studs were marginal in relation to conventional studs ( E lhajj 2006). Based 2011 RS Means cost data, conventional C shaped 6 inch 16 on center has an assumed cost of $3.27 per squar e foot of framed exterior wall area (labor, material and OH&P). Based upon an estimated 5% increase in costs the unit cost for a wall constructed similarly with dimpled flange studs is assumed to be $3.43 Ceramic Coated Studs In this scenario, metal stu ds are coated with thermally resistant ceramic material in order to decrease the thermal bridging effect This report examined a ceramic coating manufactured by Superior Products hea dquar tered in Shawnee, Kansas marketed as Super Therm. Thermal performanc e. Manufacturer literature for SuperTherm indicates that the product has thermal conductance of 0.31 BTU /( ft 2 hr F ) However, because the thickness of the material is o nly a 16 mil coating (wet), its ability to reduce thermal bridging due to conductance is not significant. The review of existing literature indicates that the primary insulating ability of this product is its ability to reflect radiation and is typically a pplied to exterior surfaces such as roofs and holding tanks. Structural performance. The application of a ceramic coating to metal studs would not have an impact upon structural performance. Fire rating performance. A review of manufacturer literature in dicates that Super Therm meets the requirements of ASTM E 84 89 a and has a flame index

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48 would not present any fire rating issues. Figure 4 10 Thermal ceramic coated stud wall a ssembly. Cost data. Based upon price informati on from Home Depot, Super Therm retails for $475 for a 5 gallon bucket or $95 per gallon. Manufacturer literature indicate s that the product covers 100 square feet per gallon which translates to a material cost of $0.95 per square foot A 6 inch C shaped metal has approxima tely 1.75 square feet of surface area per linear foot. Therefore, the material cost per linear foot of stud is $1.66. Labor costs, per 2011 RS M eans cost data, are $0.25 per square foot for spray coating. Based upon the 1.75 square foot of surface area per linear foot of 6 inch met al stud, the labor costs per line ar foot of stud is $0.44. Based upon the above cost data, the assumed combined material and labor costs to app ly a 16 mil (wet) coat of Super Therm to 6 inc h C shaped metal studs is $2.10 per linear foot of stud. This unit price translates to nearly $63,000 of additional costs when applied to the estimated 30,000 linear feet of exterior metal studs necessary for Rinker Hall. Ceramic Coated Studs R 13 Insulation Grace Ice & Water Shield

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49 S ection Two: U Factors Using the method s approved by A SHRAE Table 5 H for above ground metal framed walls, R v alues and U f actors for each of the wall system assemblies were calculated. The results of all three of these methods are sum marized in Table 4 1. Table 4 1. R values and U f actors using ASHRAE Tabl e 5 H calculation m ethod s Wall Assembly Type Parallel Flow Method Isothermal Planes Method 2D Heat Flow Analysis Method (THERM) R Value U Factor R Value U Factor R Value U Factor Rinker Hall 28.61 0.035 30.34 0.033 22.73 0.044 Code Minimum 14.16 0.071 14.94 0.067 16.03 0.063 Slit Web Stud 23.18 0.043 23.96 0.042 22.73 0.04 1 Ridged Flange Stud 23.18 0.043 23.96 0.042 20.33 0.049 Dimpled Flange Stud 23.18 0.043 23.96 0.042 21.28 0.047 Aerogel Strip 26.73 0.037 27.82 0.036 23.26 0.043 Ceramic Coated Stud 23.19 0.043 23.99 0.042 19.23 0.052 The average R values of the assemblies using the parallel flow method, isothermal planes method and THERM are 23.17, 24.14 and 20.80, respectively. The parallel flow and isothermal planes R values pr ovide relatively close results ( the latter is on average only 4% greater than the former) However, the valu es obtained using THERM consistently reflect more conservative R values with an average differential of 10.2% less versus the parallel flow and 13.8% less versus the isothermal path method. Figure 4 11 R value calculation results comparison. 10.00 15.00 20.00 25.00 30.00 35.00 R Values Parallel Flow Method Isothermal Planes Method THERM

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50 The average U factors of the assemblies using the parallel flow method, isothermal planes method and THERM are 0.045, 0.043 and 0.049, respectively. Similarly to the R value results, the parallel flow and isothermal planes R values are relatively close; t he latter is on average slightly more than 4% greater than the former However, the values obtained using THERM consistently reflect more conservative U factors with an average differential of 7.6% higher versus the parallel flow and 11.4 % higher versus t he isothermal path method. Fi gure 4 12 U factor calculation results comparison. Parallel Path Method Results As explained in the Literature Review section of this report, the parallel path method takes a weighted average of clear wall areas and framed wall areas to measure thermal performance In the parallel path method, the U factor of the clear wall assembly area and the U factor of the framed wall assembly area are multiplied by their respective percentages of wall area and then added together. In this study, the U factors of the clear wall area s and the U factors of the framed wall area s are modified by their percentages of wall area, 92% and 8%, respectively. Appendix A of this repo rt provide s detailed results of the parallel path method on each of the wall assemblies. 0.030 0.035 0.040 0.045 0.050 0.055 0.060 0.065 0.070 0.075 U factor Parallel Flow Method Isothermal Planes Method THERM

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51 Isothermal Planes Method Results As discussed in the Literature Review section of this report, in the isothermal planes method only the materials between the interior and exterior sheathing are modified by their respective percentages of wall area. In this study, R values of the interior and exterior sheathing assemblies are taken at full value while the cavity insulation and metal framing are modified by their percen tages of wall area, 92% and 8%, respectively. Appendix B of this report provides detailed results of the parallel path method on each of the wall assemblies. 2D Heat Flow Analysis Two dimensional heat flow analysis of a Code minimum wall modeled in THERM 6.3 indicated that the assembly had a U factor of 0.0625. A graphic depiction of the THERM model for the Code minimum wall is represented in Figure 4 13. Figure 4 13. 2D heat flow analysis. Code minimum wall. R 13 Insulation Metal Stud

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52 Two dimensional heat flow analysis of the Rinker Hall wall assembly and wall assemblies incorporating the alternative products indicated the following U factors: Rinker Hall: 0.044 Slit web studs: 0.041 Ridged flange studs: 0.049 Dimpled flange studs: 0.047 Aerogel strips: 0.043 Ceramic coated studs: 0.052 Graphical depictions of each of these results similar to Figure 4 13 are included in Appendix C of this report. Section Three: Energy Analy ses The energy simulation models of Rinker Hall developed in THERM 6.3 were able to provide the heating and cooling loads specifically from exterior wall conduction. This verted to kWh for this report in order to calculate projected energy cost savings. The c achieved by dividing each of the BTU results by 3,414.3. Table 4.2 provides a summary of these results. The results reported in Table 4.2 are the proj ected decreases in energy loads as compared to the baseline Code minimum wall assembly. Detailed infor mation is available Appendices D and E of this report. Table 4 2. Total decreased energy load s from wall conduction (kWh) Wall Type Climate Zone 1 2 3 4 5 6 7 8 Dimpled Flange Stud 2,301 2,308 3,421 4,626 5,766 6,588 7,643 11,259 Ridged Flange Stud 2,530 2,683 3,764 5,091 6,344 7,249 8,412 12,392 Ceramic Coated Stud 2,668 2,729 4,105 5,557 6,921 7,914 9,180 13,526 Rinker Hall 4,144 4,159 6,165 8,363 10,399 11,901 13,794 20,358 Slit Web Stud 4,144 4,159 6,165 8,363 10,399 11,901 13,794 20,358 Aerogel Strip 4,374 4,435 6,507 8,832 10,979 12,568 14,565 21,502

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53 A graphical depicti on of these results (Figure 4.14 ) shows aerogel strips provided the greatest decrease in projected energy savings followed closely by the slit web stud alternative and the actual wall assembly used in the design and construction of Rinker Hall. Also, the projected energy cost savings in crease from warmer to colder climates. Because the slit web wall and Rinker Hall wall section s were determined to have the same energy performance abilities in the two dimensional heat flow analysis their lines in Figure 4 14 are overlaid. Figure 4 14 Decreased energy loads for each wall assembly type Section Four: Cost Analyses Energy Costs Once the decreased energy loads were established for each of the wall assembly types (Table 4 2), the next step was to apply an estimated cost per kWh of energy expected from local utilities (Table 4.3) This study used the 2011 national average rate of $0.125 per kWh as published by the US Energy Information Administration (EIA). Detailed information on the energy costs associated with each wall system assembly evaluated is included in Appendix F of this report. 0 5,000 10,000 15,000 20,000 25,000 1 2 3 4 5 6 7 8 kWh Climate Zone Dimpled Flange Stud Ridged Flange Stud Ceramic Coated Stud Rinker Hall Slit Web Stud Aerogel Strip

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54 Table 4 3 Projected annual energy savings Wall Type Climate Zone 1 2 3 4 5 6 7 8 Dimpled Flange Stud $288 $288 $428 $578 $721 $824 $955 $1,407 Ridged Flange Stud $316 $335 $471 $636 $793 $906 $1,052 $1,549 Ceramic Coated Stud $334 $341 $513 $695 $865 $989 $1,147 $1,691 Rinker Hall $518 $520 $771 $1,045 $1,300 $1,488 $1,724 $2,545 Slit Web Stud $518 $520 $771 $1,045 $1,300 $1,488 $1,724 $2,545 Aerogel Strip $547 $554 $813 $1,104 $1,372 $1,571 $1,821 $2,688 Similarly to the projected decreased energy loads f rom wall conduction (Figure 4 14 ), graphical depicti on of these results (Figure 4.15 ) indicated that aerogel strips provided the greatest decrease in projected energy cost savings followed closely by the slit web stud alternative and the actual wall assembly used in the design and construction of Rinker Hall. Likewise, the projected ene rgy cost savings increase from warmer to colder climates. Figure 4 15 Decreased energy costs for each wall assembly type Construction Costs each of the wall assembly types based upon the square feet of opaque exterior wall area. These unit cost estimates are provided in Table 4 4 of this report. $0 $500 $1,000 $1,500 $2,000 $2,500 $3,000 1 2 3 4 5 6 7 8 Annual Energy Costs Climate Zone Dimpled Flange Stud Ridged Flange Stud Ceramic Coated Stud Rinker Hall Slit Web Stud Aerogel Strip

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55 Table 4 4. Construction unit costs per s f of opaque exterior wall area Material Code Mini mum ($/sf) Slit Web Stud ($/sf) Dimpled Flange Stud ($/sf) Ridged Flange Stud ($/sf) Rinker Hall ($/sf) Aerogel Strips ($/sf) Ceramic Coated Stud ($/sf) Metal Stud $3.27 $3.27 $6.00 $6.00 Ridged Flange Stud $3.76 Slit Web Stud $3.43 Dimpled Flange Stud $3.43 Aerogel Strip $2.16 Ceramic Coating $4.62 Fiberglass Insulation (R 13) $0.76 Fiberglass Insulation (R 19) $0.82 $0.82 $0.82 $0.82 $0.82 $0.82 2x2 Wood Blocking $1.27 Semi Rigid Insulation (1.5") $1.17 Gypsum Board, 5/8" $1.40 $1.40 $1.40 $1.40 $1.40 $1.40 $1.40 TOTAL PER SF $5.43 $5.65 $5.65 $5.98 $7.93 $10.38 $12.84 Life Cycle Costs this report provided insight regarding the year that projected energy savings could eclipse the increased initial investments for the alternative metal stud products. The estimated breakeven years for each alternative product in each of the eight US clima te zones are provided in Table 4 5 and dep icted graphically in Figure 4 16 So me of the breakeven projections, including those for the Rinker Hall, ceramic coated stud and aerogel strip wall assemblies, fell outs ide of the 30 year study period and were no t determined by this research. Table 4 5 Estimated years to reach break e ven Wall Type ASHRAE Climate Zones 1 2 3 4 5 6 7 8 Rinker Hall >30 >30 >30 >30 >30 >30 27.7 19.7 Ceramic Coated Stud >30 >30 >30 >30 >30 >30 >30 >30 Aerogel Strip >30 >30 >30 > 30 >30 >30 >30 22.1 Dimpled Flange Stud 9.8 9.8 6.7 5 4.1 3.6 3.1 2.1 Ridged Flange Stud 21 20 14.6 11 9 7.9 6.8 4.7 Slit Web Stud 5.6 5.6 3.8 2.8 2.3 2 1.7 1.2

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56 A graphical depiction o f the projected breakeven years for each of the wall systems evaluated is provided in Figure 4 15. Figure 4 16 Projected breakeven years. 0 5 10 15 20 25 30 1 2 3 4 5 6 7 8 Breakeven Year Climate Zone Rinker Hall Ceramic Coated Stud Aerogel Strip Dimpled Flange Stud Ridged Flange Stud Slit Web Stud

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57 CHAPTER 5 SUMMARY, CONCLUSIONS AND RECOMMENDATIONS Summary The goal of this research was to identify either a metal stud substitute or additive product capable of reducing the thermal bridging effect in exterior building walls. This research considered thermal effectiveness, structural properties, combustibility and overall life cycle costs. To evaluate the products selected for research, the thermal eff ectiveness of each of the alternatives was modeled as substitute components within a Code minimum exterior wall assembly using two dimensional heat transfer analysis software. This process determined the U factors of each of the wall assemblies which were then entered into a building energy simulation model based upon the design of Rinker Hall at the University of Florida. Each of the energy models provided data regarding the cooling and heating loads specifically related to conduction through the exterior wall systems. To further understand how climatic variances could affect thermal performance, simulations were created for each of the ener gy models in each of eight US climatic zones. The national average for the cost of electricity per unit in kilowatt hours was then applied to the energy loads determined for each model. Additionally, cost estimates were prepared for each of the wall type assemblies to understand the initial cost implications associated with the alternative products. The energy load differentials were then applied to life cycle cost analyses to determine the overall cost effectiveness of each of the alternative produ cts ov er an extended period of 3 0 years. This process took initial costs, projected energy savings, discount rates and energy inflation rates into account to determine which of the products if any, w ould be recommended by this study.

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58 Matrix of Results T he matr ix of results ( Table 5.1) visually depicts the recommendations of this study for each of the products in each of the eight US climatic zones. Superior products were able to balance the higher initial construction costs against the projected annual energy saving in fewer years. The term used for year that energy savings was anticipated to ecli pse initial costs is the criteria: Good: Break even in 10 years or less Fair: Break even in 10 to 20 years Poor: Break even greater than 20 years Table 5 1. Matrix of results. Wall Type ASHRAE Climate Zones 1 2 3 4 5 6 7 8 Ceramic Coated Stud Aerogel Strip Rinker Hall Ridged Flange Stud Dimpled Flange Stud Slit Web Stud The ceramic coated stud received poor ratings in all climate zones because it provided the least degree of thermal performance and highest initial costs. Ceramic coated did not achieve breakeven within the 30 year study period in any climate zone. The thermal ability of this product appears to be re flecting solar radiation. Although it has good resistance to heat conduction, a relatively thin coating applied to metal studs does not provide sufficient energy Good Fair Poor

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59 savings to overcome its initial costs. The application of ceramic coatings to metal studs to reduce thermal bridging cannot be recommended by this study. Although aerogel strips provided the highest degree of projected energy savings, the material also had the second highest initial costs. Similarly to the ceramic coated stud, its high initial c osts were too great to be overcome by projected energy saving. The exterior wall assembly with aerogel strips incorporated only achieve d breakeven in Climate Zone 8 in year 27.7. Based upon the evaluation of this research, aerogel strips, at their cu rrent price point, cannot be recommended by this study and received poor ratings in all eight climate zones. The ridged flange stud concept was better able to balance energy saving against initial costs; however, the product received a poor rating in Clima te Zone 1 because the projected break even year was not estimated to occur until year 21 The product fared better in and received fair ratings in climate zones 2, 3, and 4 with break even projected in occur years 20, 14.6 and 11, respective ly. The ridged flange stud received good rating s in Climate Zone 5, 6, 7 and 8 with energy savings project ed to surpass initial costs within the initial ten year period of the study Based upon this study, ridged flange studs can be recommended as a product capable of r educing the effects of metal thermal bridging in Climate Zones 5, 6, 7 and 8. good ratings in all climate zones. Dimple flange studs were able to achieve breakeven within the initial ten year study period in all eight climate zones. Based upon this study, dimpled flange studs can be recommended as a product capable of reducing the effects of metal thermal bridging in all eight US climate zones The best performing product evaluated in this study was the slit web stud. This product received good ratings in all eight climate zones with breakeven years all occurring within the

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60 initial ten year period Based upon this study, slit web studs can be recommended as a product capa ble of reducing the effects of metal thermal bridging in all eight US climate zones. Conclusions It is possible to significantly reduce thermal heat transfer through metal stud framing in Altering th e design/configuration of metal studs achieves greater thermal performance than attempting to reduce thermal bridging through the application of topical insulating products. Due to the greater area available to manipulate, higher thermal performance can be achieved by altering the web area of metal studs rather than the flange areas. The application of all of the methods evaluated achieved better results in colder climates than warmer ones. Limitations It is important to note that this research is based up on using the design and function of Rinker Hall at the University of Florida as base model. Although the U factor inputs were adjusted for each model in each climate zone, the design and function of Rinker Hall is nonetheless reflective of a specific buil ding typology: educational buildings with a higher than average internal load. It is possible that a change in building type could yield differing results. Recommendations for Future Study Although this study provides valuable insight into the reduction of energy costs associated with thermal heat transfer through the opaque portions of above grade exterior wall systems there are many avenues available for further refinement and research. Some of the possibilities include: Alternative materials to steel that might be readily available, less thermally conductive, and have equivalent or superior structural and fire rating capabilities. The initial costs to manufacture and install an alternative stud product using such a hypothetical material wo uld be crit ical considerations to evaluate. Ideally, such a product could be derived from existing waste streams to lessen the impacts upon the environment and existing natural resources. One possibility that was suggested to this researcher, although it has not been explored, is the use of recycled tire materials.

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61 Possible alternative metal stud configurations to combine some of the ideas presented in this study. Perhaps a combination s lit web and dimpled flange stud would provide even greater thermal performance than either single configuration alone. Deeper research into why the solutions presented in this study are more effective in colder climates than in warmer areas. The products studied were across the board more capable of resisting the transfer of heat out of a building than into a building. Research that considers the interactions and effects of thermal bridging between metal stud framing and other building components or assemblies such as balconies, window units or slab/roof intersections. Based upon the conversation with the representative that designed the ridged flange product (ThermaChannel), getting their product to market has been difficult due to the reluctance of existing metal stud manufactures to produce non standard studs Perhap s further research could convince building owners, designers and Code authorities of the effectiveness of alternative stud designs to reduce building energy costs. This may provide encouragement to stud manufacturers to start producing alternately configu red metal studs that can help reduce thermal bridging in metal framed exterior walls.

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62 APPENDIX A U FACTOR CALCULATIONS PARALLEL PATH METHOD Table A 1 Code minimum w all U factor. Parallel path m ethod Element R Value Data Source Cavity Stud Exterior Air Film 0.17 0.17 ASHRAE 90.1 2010 (Section A9.4.1) 7/8" Stucco Assembly 0.18 0.18 ColoradoEnergy.org Grace Ice & Water Shield 0.00 0.00 Manufacturer Data Sheet 5/8" Exterior Sheathing 0.56 0.56 ColoradoEnergy.org Metal Stud 0.69 ASHRAE Fundamentals 2009 (Chapter 27) Fiberglass Batt Insulation (R 13) 13.00 ColoradoEnergy.org Gypsum Board, 5/8" 0.56 0.56 Standard 90.1 2007 (Sec. A9.4.1) Interior Air Film 0.68 0.68 ASHRAE 90.1 2010 (Section A9.4.1) TOTAL R VALUE 15.15 2.84 OVERALL R VALUE 14.16 Weighted average: 92% cavity / 8% framing U FACTOR 0.071 (15.15x .92) + (2.84 x 0.08) = 14.16 Table A 2 Rinker exterior wall U factor. Parallel path m ethod Element R Value Data Source Cavity Stud Exterior Air Film 0.17 0.17 ASHRAE 90.1 2010 (Section A9.4.1) Alucobond Alum Panel 4mm 0.05 0.05 Manufacturer Data Sheet Air Cavity 0.91 0.91 ASHRAE 90.1 2010 (Table A9.4A) Grace Ice & Water Shield 0.00 0.00 Manufacturer Data Sheet 5/8" Exterior Sheathing 0.56 0.56 ColoradoEnergy.org Metal Stud 0.69 ASHRAE Fundamentals 2009 (Chapter 27) 2x2 Wood Blocking 1.88 ColoradoEnergy.org Cellulose Insulation (6") 22.80 ColoradoEnergy.org Semi Rigid Insulation (1 1/2") 4.50 4.50 ColoradoEnergy.org Gypsum Board, 5/8" 0.56 0.56 ASHRAE Standard 90.1 2007 (Sec. A9.4.1) Interior Air Film 0.68 0.68 ASHRAE 90.1 2010 (Section A9.4.1) TOTAL R VALUE 30.23 10.00 OVERALL R VALUE 28.61 Weighted average: 92% cavity / 8% framing U FACTOR 0.035 (30.23 x .92) + (10.00 x 0.08) = 28.61 Table A 3. Slit web, ridged & dimpled flange stud wall U factors. Parallel p ath method. Element R Value Data Source Cavity Stud Exterior Air Film 0.17 0.17 ASHRAE 90.1 2010 (Section A9.4.1) 7/8" Stucco Assembly 0.18 0.18 ColoradoEnergy.org Grace Ice & Water Shield 0.00 0.00 Manufacturer Data Sheet 5/8" Exterior Sheathing 0.56 0.56 ColoradoEnergy.org Metal Stud 0.69 ASHRAE Fundamentals 2009 (Chapter 27) Cellulose Insulation (6") 22.80 ColoradoEnergy.org Gypsum Board, 5/8" 0.56 0.56 Standard 90.1 2007 (Sec. A9.4.1) Interior Air Film 0.68 0.68 ASHRAE 90.1 2010 (Section A9.4.1) TOTAL R VALUE 24.95 2.84 OVERALL R VALUE 23.18 U FACTOR 0.043

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63 T able A 4 Aerogel strip wall assembly U factor. Parallel path m ethod. Element R Value Data Source Cavity Stud Exterior Air Film 0.17 0.17 ASHRAE 90.1 2010 (Section A9.4.1) 7/8" Stucco Assembly 0.18 0.18 ColoradoEnergy.org Grace Ice & Water Shield 0.00 0.00 Manufacturer Data Sheet 5/8" Exterior Sheathing 0.56 0.56 ColoradoEnergy.org Metal Stud 0.69 ASHRAE Fundamentals 2009 (Chapter 27) Aerogel Strip (3/8") 3.86 Manufacturer Data Sheet Cellulose Insulation (6") 22.80 ColoradoEnergy.org Gypsum Board, 5/8" 0.56 0.56 Standard 90.1 2007 (Sec. A9.4.1) Interior Air Film 0.68 0.68 ASHRAE 90.1 2010 (Section A9.4.1) TOTAL R VALUE 28.81 2.84 OVERALL R VALUE 26.73 U FACTOR 0.037 Table A 5 Thermal c era mic coated stud assembly U factor. Parallel path m ethod. Element R Value Data Source Cavity Stud Exterior Air Film 0.17 0.17 ASHRAE 90.1 2010 (Section A9.4.1) 7/8" Stucco Assembly 0.18 0.05 ColoradoEnergy.org Grace Ice & Water Shield 0.00 0.00 Manufacturer Data Sheet 5/8" Exterior Sheathing 0.56 0.56 ColoradoEnergy.org Metal Stud 0.69 ASHRAE Fundamentals 2009 (Chapter 27) Thermal Ceramic Coating 0.31 Manufacturer Data Sheet Cellulose Insulation (6") 22.80 ColoradoEnergy.org Gypsum Board, 5/8" 0.56 0.56 Standard 90.1 2007 (Sec. A9.4.1) Interior Air Film 0.68 0.68 ASHRAE 90.1 2010 (Section A9.4.1) TOTAL R VALUE 24.95 3.02 OVERALL R VALUE 23.19 U FACTOR 0.043

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64 APPENDIX B U FACTOR C AL CULATIONS ISOTHERMAL PLANES ME THOD Table B 1 Code minimum exterior wall U factor. Isothermal planes m ethod. Material Int Sheath Cav Insul Stud Ext Sheath Data Source Exterior Air Film 0.17 ASHRAE 90.1 2010 (Section A9.4.1) 7/8" Stucco Assembly 0.05 Manufacturer Data Sheet Air Cavity 0.91 ASHRAE 90.1 2010 (Table A9.4A) Ice & Water Shield 0.00 Manufacturer Data Sheet 5/8" Exterior Sheathing 0.56 ColoradoEnergy.org Metal Stud 0.69 ASHRAE Fundamentals 2009 (Cpt 27) Fiberglass Insul. (R 13) 13.00 ColoradoEnergy.org Gypsum Board, 5/8" 0.56 Standard 90.1 2007 (Sec. A9.4.1) Interior Air Film 0.68 ASHRAE 90.1 2010 (Section A9.4.1) TOTAL R VALUE 1.24 13.00 0.69 1.69 OVERALL R VALUE 14.94 U FACTOR 0.067 Table B 2 Rinker Hall exterior wall U f actor. Isothermal planes m ethod. Material Int Sheath Cav Insul Stud Ext Sheath Data Source Exterior Air Film 0.17 ASHRAE 90.1 2010 (Section A9.4.1) Alucobond Alum Panel 0.05 Manufacturer Data Sheet Air Cavity 0.91 ASHRAE 90.1 2010 (Table A9.4A) Ice & Water Shield 0.00 Manufacturer Data Sheet 5/8" Exterior Sheathing 0.56 ColoradoEnergy.org Metal Stud 0.69 ASHRAE Fundamentals 2009 (Cptr 27) Cellulose Insulation (6") 22.80 ColoradoEnergy.org 2x2 Wood Blocking 1.88 ColoradoEnergy.org Semi Rigid Insulation 4.50 ColoradoEnergy.org Gypsum Board, 5/8" 0.56 Standard 90.1 2007 (Sec. A9.4.1) Interior Air Film 0.68 ASHRAE 90.1 2010 (Section A9.4.1) TOTAL R VALUE 7.62 22.80 0.69 1.69 OVERALL R VALUE 30.34 U FACTOR 0.033 Table B 3 Slit web, r idged & dimpled flange wall U factors. Isothermal p lanes method. Material Int Sheath Cav Insul Stud Ext Sheath Data Source Exterior Air Film 0.17 ASHRAE 90.1 2010 (Section A9.4.1) 7/8" Stucco Assembly 0.05 Manufacturer Data Sheet Air Cavity 0.91 ASHRAE 90.1 2010 (Table A9.4A) Ice & Water Shield 0.00 Manufacturer Data Sheet 5/8" Exterior Sheathing 0.56 ColoradoEnergy.org Metal Stud 0.69 ASHRAE Fundamentals 2009 (Cptr 27) Cellulose Insulation (6") 22.80 ColoradoEnergy.org Gypsum Board, 5/8" 0.56 Standard 90.1 2007 (Sec. A9.4.1) Interior Air Film 0.68 ASHRAE 90.1 2010 (Section A9.4.1) TOTAL R VALUE 1.24 22.80 0.69 1.69 OVERALL R VALUE 23.96 U FACTOR 0.042

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65 Tabl e B 4 Aerogel strip wall assembly U factor. Isothermal planes m ethod. Material Int Sheath Cav Insul Stud Ext Sheath Data Source Exterior Air Film 0.17 ASHRAE 90.1 2010 (Section A9.4.1) 7/8" Stucco Assembly 0.05 Manufacturer Data Sheet Air Cavity 0.91 ASHRAE 90.1 2010 (Table A9.4A) Grace Ice & Water Shield 0.00 Manufacturer Data Sheet 5/8" Exterior Sheathing 0.56 ColoradoEnergy.org Metal Stud 0.69 ASHRAE Fundamentals 2009 (Chapter 27) Cellulose Insulation (6") 22.80 ColoradoEnergy.org Aerogel Strip (3/8") 3.86 Manufacturer Data Sheet Gypsum Board, 5/8" 0.56 Standard 90.1 2007 (Sec. A9.4.1) Interior Air Film 0.68 ASHRAE 90.1 2010 (Section A9.4.1) TOTAL R VALUE 5.10 22.80 0.69 1.69 OVERALL R VALUE 27.82 U FACTOR 0.036 Table B 5 Thermal c eramic coated stud assembly U factor. Isothermal planes m ethod. Material Int Sheath Cav Insul Stud Ext Sheath Data Source Exterior Air Film 0.17 ASHRAE 90.1 2010 (Section A9.4.1) 7/8" Stucco Assembly 0.05 Manufacturer Data Sheet Air Cavity 0.91 ASHRAE 90.1 2010 (Table A9.4A) Grace Ice & Water Shield 0.00 Manufacturer Data Sheet 5/8" Exterior Sheathing 0.56 ColoradoEnergy.org Metal Stud 0.69 ASHRAE Fundamentals 2009 (Chapter 27) Thermal Ceramic Coating 0.31 Manufacturer Data Sheet Cellulose Insulation (6") 22.80 ColoradoEnergy.org Gypsum Board, 5/8" 0.56 Standard 90.1 2007 (Sec. A9.4.1) Interior Air Film 0.68 ASHRAE 90.1 2010 (Section A9.4.1) TOTAL R VALUE 1.24 22.80 1.00 1.69 OVERALL R VALUE 23.99 U FACTOR 0.042

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66 APPENDIX C U FACTOR C AL CULATIONS 2D HEAT FLOW ANALYSI S Figure C 1. 2D heat flow analysis. Rinker Hall wall. Cavity Insulation Metal Stud 2x2 Wood Blocking

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67 Figure C 2. 2D heat flow analysis. Ridged flange stud wall. Figure C 3. 2D heat flow analysis. Slit web stud wall. Cavity Insulation Ridged Flange Stud Cavity Insulation Slit Web Stud

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68 Figure C 4. 2D heat flow analysis. Dimpled flange stud wall. Figure C 5 2D heat flow analysis. Aerogel strip stud wall. Exterior Sheathing Cavity Insulation Dimpled Flange Stud Cavity Insulation Dimpled Flange Stud Aerogel Strip Gypsum Board

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69 Figure C 6. 2D heat flow analysis. Ceramic coated stud wall. Cavity Insulation Ceramic Coated Stud

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70 APPENDIX D DECREASED HEATING LO ADS FROM WALL CONDUC TION Table D 1. Decreased heating loads. Heating loads. Zone 1 Miami, FL Wall Type Building heat load from wall conduction (Btu) Building heat load from wall conduction (kWh) Decreased heat load from wall conduction (kWh) Code Minimum (20,269,405.13) (5,936.62) Rinker Hall (14,379,143.01) (4,211.45) 1,725.17 Ridged Flange Stud (16,672,147.77) (4,883.04) 1,053.59 Slit Web Stud (14,379,143.01) (4,211.45) 1,725.17 Dimpled Flange Stud (16,997,383.84) (4,978.29) 958.33 Aerogel Strip (14,053,234.30) (4,115.99) 1,820.63 Ceramic Coated Stud (16,476,244.77) (4,825.66) 1,110.96 Table D 2. Decreased heating loads. Zone 2 Gainesville, FL. Wall Type Building heat load from wall conduction (Btu) Building heat load from wall conduction (kWh) Decreased heat load from wall conduction (kWh) Code Minimum (19,931,768.01) (5,837.73) Rinker Hall (14,141,197.52) (4,141.76) 1,695.98 Ridged Flange Stud (16,541,683.97) (4,844.82) 992.91 Slit Web Stud (14,141,197.52) (4,141.76) 1,695.98 Dimpled Flange Stud (16,718,126.31) (4,896.50) 941.23 Aerogel Strip (14,053,234.30) (4,115.99) 1,721.74 Ceramic Coated Stud (16,476,244.77) (4,825.66) 1,012.07 Table D 3. Decreased heating loads. Zone 3 Atlanta, GA. Wall Type Building heat load from wall conduction (Btu) Building heat load from wall conduction (kWh) Decreased heat load from wall conduction (kWh) Code Minimum (58,985,465.71) (17,276.01) Rinker Hall (42,070,213.26) (12,321.77) 4,954.24 Ridged Flange Stud (48,668,456.87) (14,254.30) 3,021.71 Slit Web Stud (42,070,213.26) (12,321.77) 4,954.24 Dimpled Flange Stud (49,610,464.79) (14,530.20) 2,745.80 Aerogel Strip (41,127,952.71) (12,045.79) 5,230.21 Ceramic Coated Stud (47,730,397.71) (13,979.56) 3,296.45

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71 Table D 4. Decreased heating loads. Zone 4 Seattle, WA. Wall Type Building heat load from wall conduction (Btu) Building heat load from wall conduction (kWh) Decreased heat load from wall conduction (kWh) Code Minimum (96,791,800.24) (28,348.94) Rinker Hall (69,103,226.21) (20,239.35) 8,109.59 Ridged Flange Stud (79,916,261.71) (23,406.34) 4,942.61 Slit Web Stud (69,103,226.21) (20,239.35) 8,109.59 Dimpled Flange Stud (81,457,244.63) (23,857.67) 4,491.27 Aerogel Strip (67,555,755.41) (19,786.12) 8,562.82 Ceramic Coated Stud (78,371,644.67) (22,953.94) 5,395.00 Table D 5. Decreased heating loads. Zone 5 Chicago, IL. Wall Type Building heat load from wall conduction (Btu) Building heat load from wall conduction (kWh) Decreased heat load from wall conduction (kWh) Code Minimum (117,846,342.29) (34,515.52) Rinker Hall (84,154,567.14) (24,647.68) 9,867.84 Ridged Flange Stud (97,309,746.64) (28,500.64) 6,014.88 Slit Web Stud (84,154,567.14) (24,647.68) 9,867.84 Dimpled Flange Stud (99,183,535.68) (29,049.45) 5,466.07 Aerogel Strip (82,269,322.62) (24,095.52) 10,420.00 Ceramic Coated Stud (95,436,690.17) (27,952.05) 6,563.47 Table D 6. Decreased heating loads. Zone 6 Helena, MT. Wall Type Building heat load from wall conduction (Btu) Building heat load from wall conduction (kWh) Decreased heat load from wall conduction (kWh) Code Minimum (141,073,991.96) (41,318.57) Rinker Hall (100,976,267.60) (29,574.52) 11,744.05 Ridged Flange Stud (116,664,488.43) (34,169.37) 7,149.20 Slit Web Stud (100,976,267.60) (29,574.52) 11,744.05 Dimpled Flange Stud (118,893,149.14) (34,822.12) 6,496.45 Aerogel Strip (98,726,579.22) (28,915.61) 12,402.96 Ceramic Coated Stud (114,426,874.79) (33,514.01) 7,804.56

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72 Table D 7. Decreased heating loads. Zone 7 Minot, ND. Wall Type Building heat load from wall conduction (Btu) Building heat load from wall conduction (kWh) Decreased heat load from wall conduction (kWh) Code Minimum (163,279,634.15) (47,822.29) Rinker Hall (116,665,065.81) (34,169.54) 13,652.75 Ridged Flange Stud (134,869,610.23) (39,501.39) 8,320.89 Slit Web Stud (116,665,065.81) (34,169.54) 13,652.75 Dimpled Flange Stud (137,466,462.35) (40,261.98) 7,560.31 Aerogel Strip (114,054,236.59) (33,404.87) 14,417.42 Ceramic Coated Stud (132,274,875.73) (38,741.43) 9,080.85 Table D 8. Decreased heating loads. Zone 8 Nome, AK. Wall Type Building heat load from wall conduction (Btu) Building heat load from wall conduction (kWh) Decreased heat load from wall conduction (kWh) Code Minimum (240,884,680.53) (70,551.70) Rinker Hall (172,514,383.18) (50,527.01) 20,024.69 Ridged Flange Stud (199,253,916.50) (58,358.64) 12,193.06 Slit Web Stud (172,514,383.18) (50,527.01) 20,024.69 Dimpled Flange Stud (203,058,233.65) (59,472.87) 11,078.83 Aerogel Strip (168,679,075.02) (49,403.71) 21,148.00 Ceramic Coated Stud (195,447,043.96) (57,243.66) 13,308.04

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73 APPENDIX E DECREASED COOLING LO ADS FROM WALL CONDUC TION Table E 1. Decreased cooling loads. Zone 1 Miami, FL. Wall Type Building cool load from wall conduction (Btu) Building cool load from wall conduction (kWh) Decreased cool load from wall conduction (kWh) Code Minimum 28,542,717.93 8,359.76 Rinker Hall 20,283,688.06 5,940.80 2,418.95 Ridged Flange Stud 23,500,525.12 6,882.97 1,476.79 Slit Web Stud 20,283,688.06 5,940.80 2,418.95 Dimpled Flange Stud 23,957,464.33 7,016.80 1,342.96 Aerogel Strip 19,825,529.59 5,806.62 2,553.14 Ceramic Coated Stud 23,225,568.24 6,802.44 1,557.32 Table E 2. Decreased cooling loads. Zone 2 Gainesville, FL. Wall Type Building cool load from wall conduction (Btu) Building cool load from wall conduction (kWh) Decreased cool load from wall conduction (kWh) Code Minimum 29,089,232.15 8,519.82 Rinker Hall 20,678,604.61 6,056.47 2,463.35 Ridged Flange Stud 23,317,362.55 6,829.32 1,690.50 Slit Web Stud 20,678,604.61 6,056.47 2,463.35 Dimpled Flange Stud 24,423,253.35 7,153.22 1,366.60 Aerogel Strip 19,825,529.59 5,806.62 2,713.21 Ceramic Coated Stud 23,225,568.24 6,802.44 1,717.38 Table E 3. Decreased cooling loads. Zone 3 Atlanta, GA. Wall Type Building cool load from wall conduction (Btu) Building cool load from wall conduction (kWh) Decreased cool load from wall conduction (kWh) Code Minimum 13,882,372.08 4,065.95 Rinker Hall 9,748,862.03 2,855.30 1,210.65 Ridged Flange Stud 11,346,349.46 3,323.18 742.77 Slit Web Stud 9,748,862.03 2,855.30 1,210.65 Dimpled Flange Stud 11,577,095.29 3,390.77 675.18 Aerogel Strip 9,524,134.79 2,789.48 1,276.47 Ceramic Coated Stud 11,120,329.43 3,256.99 808.96

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74 Table E 4. Decreased cooling loads. Zone 4 Seattle, WA. Wall Type Building cool load from wall conduction (Btu) Building cool load from wall conduction (kWh) Decreased cool load from wall conduction (kWh) Code Minimum 3,913,432.48 1,146.19 Rinker Hall 3,049,117.41 893.04 253.15 Ridged Flange Stud 3,405,412.29 997.40 148.79 Slit Web Stud 3,049,117.41 893.04 253.15 Dimpled Flange Stud 3,453,218.99 1,011.40 134.79 Aerogel Strip 2,994,142.69 876.94 269.25 Ceramic Coated Stud 3,359,529.15 983.96 162.23 Table E 5. Decreased cooling loads. Zone 5 Chicago, IL. Wall Type Building cool load from wall conduction (Btu) Building cool load from wall conduction (kWh) Decreased cool load from wall conduction (kWh) Code Minimum 5,535,741.81 1,621.34 Rinker Hall 3,723,013.86 1,090.42 530.92 Ridged Flange Stud 4,411,249.86 1,291.99 329.35 Slit Web Stud 3,723,013.86 1,090.42 530.92 Dimpled Flange Stud 4,511,267.81 1,321.29 300.05 Aerogel Strip 3,625,976.98 1,062.00 559.34 Ceramic Coated Stud 4,313,781.72 1,263.45 357.89 Table E 6. Decreased cooling loads. Zone 6 Helena, MT. Wall Type Building cool load from wall conduction (Btu) Building cool load from wall conduction (kWh) Decreased cool load from wall conduction (kWh) Code Minimum 942,765.41 276.12 Rinker Hall 405,972.92 118.90 157.22 Ridged Flange Stud 602,663.77 176.51 99.61 Slit Web Stud 405,972.92 118.90 157.22 Dimpled Flange Stud 629,384.59 184.34 91.78 Aerogel Strip 380,617.00 111.48 164.65 Ceramic Coated Stud 569,731.93 166.87 109.26

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75 Table E 7. Decreased cooling loads. Minot, ND. Wall Type Building cool load from wall conduction (Btu) Building cool load from wall conduction (kWh) Decreased cool load from wall conduction (kWh) Code Minimum 910,557.46 266.69 Rinker Hall 429,920.18 125.92 140.77 Ridged Flange Stud 598,161.94 175.19 91.50 Slit Web Stud 429,920.18 125.92 140.77 Dimpled Flange Stud 628,238.13 184.00 82.69 Aerogel Strip 405,894.74 118.88 147.81 Ceramic Coated Stud 572,621.14 167.71 98.98 Table E 8. Decreased cooling loads. Zone 8 Nome, AK. Wall Type Building cool load from wall conduction (Btu) Building cool load from wall conduction (kWh) Decreased cool load from wall conduction (kWh) Code Minimum (4,652,306.25) ( 1,362.59 ) Rinker Hall (3,512,765.16) ( 1,028.84 ) 333.76 Ridged Flange Stud (3,973,454.73) ( 1,163.77 ) 198.83 Slit Web Stud (3,512,765.16) ( 1,028.84 ) 333.76 Dimpled Flange Stud (4,037,323.83) ( 1,182.47 ) 180.12 Aerogel Strip (3,444,557.94) ( 1,008.86 ) 353.73 Ceramic Coated Stud (3,907,707.04) ( 1,144.51 ) 218.08

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76 APPENDIX F ANNUAL ENERGY SAVING S Table F 1. Annual Energy Savings. Zone 1 Miami, FL. Wall Type Total decreased load from wall conduction (kWh) Annual Energy Savings ($0.125 per kWh) Code Minimum Rinker Hall 4,144.13 $518.02 Ridged Flange Stud 2,530.37 $316.30 Slit Web Stud 4,144.13 $518.02 Dimpled Flange Stud 2,301.28 $287.66 Aerogel Strip 4,373.77 $546.72 Ceramic Coated Stud 2,668.28 $333.54 Table F 2. Annual Energy Savings. Zone 2 Gainesville, FL. Wall Type Total decreased load from wall conduction (kWh) Annual Energy Savings ($0.125 per kWh) Code Minimum Rinker Hall 4,159.33 $519.92 Ridged Flange Stud 2,683.41 $335.43 Slit Web Stud 4,159.33 $519.92 Dimpled Flange Stud 2,307.83 $288.48 Aerogel Strip 4,434.95 $554.37 Ceramic Coated Stud 2,729.46 $341.18 Table F 3. Annual Energy Savings. Zone 3 Atlanta, GA. Wall Type Total decreased load from wall conduction (kWh) Annual Energy Savings ($0.125 per kWh) Code Minimum Rinker Hall 6,164.88 $770.61 Ridged Flange Stud 3,764.47 $470.56 Slit Web Stud 6,164.88 $770.61 Dimpled Flange Stud 3,420.99 $427.62 Aerogel Strip 6,506.68 $813.33 Ceramic Coated Stud 4,105.41 $513.18

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77 Table F 4. Annual Energy Savings. Zone 4 Seattle, WA. Wall Type Total decreased load from wall conduction (kWh) Annual Energy Savings ($0.125 per kWh) Code Minimum Rinker Hall 8,362.74 $1,045.34 Ridged Flange Stud 5,091.40 $636.42 Slit Web Stud 8,362.74 $1,045.34 Dimpled Flange Stud 4,626.06 $578.26 Aerogel Strip 8,832.07 $1,104.01 Ceramic Coated Stud 5,557.23 $694.65 Table F 5. Annual Energy Savings. Zone 5 Chicago, IL. Wall Type Total decreased load from wall conduction (kWh) Annual Energy Savings ($0.125 per kWh) Code Minimum Rinker Hall 10,398.76 $1,299.85 Ridged Flange Stud 6,344.23 $793.03 Slit Web Stud 10,398.76 $1,299.85 Dimpled Flange Stud 5,766.13 $720.77 Aerogel Strip 10,979.35 $1,372.42 Ceramic Coated Stud 6,921.36 $865.17 Table F 6. Annual Energy Savings. Zone 6 Helena, MT. Wall Type Total decreased load from wall conduction (kWh) Annual Energy Savings ($0.125 per kWh) Code Minimum Rinker Hall 11,901.27 $1,487.66 Ridged Flange Stud 7,248.81 $906.10 Slit Web Stud 11,901.27 $1,487.66 Dimpled Flange Stud 6,588.24 $823.53 Aerogel Strip 12,567.60 $1,570.95 Ceramic Coated Stud 7,913.82 $989.23

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78 Table F 7. Annual Energy Savings. Zone 7 Minot, ND. Wall Type Total decreased load from wall conduction (kWh) Annual Energy Savings ($0.125 per kWh) Code Minimum Rinker Hall 13,793.52 $1,724.19 Ridged Flange Stud 8,412.39 $1,051.55 Slit Web Stud 13,793.52 $1,724.19 Dimpled Flange Stud 7,643.00 $955.37 Aerogel Strip 14,565.23 $1,820.65 Ceramic Coated Stud 9,179.83 $1,147.48 Table F 8. Annual Energy Savings. Zone 8 Nome, AK. Wall Type Total decreased load from wall conduction (kWh) Annual Energy Savings ($0.125 per kWh) Code Minimum Rinker Hall 20,358.44 $2,544.81 Ridged Flange Stud 12,391.89 $1,548.99 Slit Web Stud 20,358.44 $2,544.81 Dimpled Flange Stud 11,258.95 $1,407.37 Aerogel Strip 21,501.73 $2,687.72 Ceramic Coated Stud 13,526.12 $1,690.77

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79 AP PENDIX G LIFE CYCLE COST ANAL YSES

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127 LIST OF REFERENCES ASHRAE (2 009 ). Handook: Fundamentals. American Society of Heating, Refrigerating and Air Conditioning Engineers Atlanta, GA. ASHRAE. (2010). Standard 90.1 2010: Energy Standard for Buildings Except Low Rise Residential Building American Society of Heating, Refrigerating and Air Conditioning Engineers Atlanta, GA. Ben Nakhi A. E. (2003). Development of an integrated dyna mic thermal bridging assessment environment. Energy and Buildings, 35 375 382. Brock, L. (2005). Designing the Exterior Wall: An Architectural Guide John Wiley & Sons, Hoboken, NJ. C hristian J. E. & K osny J. (1996). Thermal performance and wall ratin gs. A SHRAE Journal American Society of Heating Refrigerating and Air Conditioning Engineers, 38 56 58 Clarke, J. A. (2001). Energy Simulation in Building Design Butterworh Heinemann, Woburn, MA. C oats P. (2007). Modeling and design approach for treatment of highly thermally conductive architectural elements in high performance buildings in mixed c limates. A SHRAE Journal American Society of Heating Refrigerating and Air Conditioning Engineers, 47 44 48. Code of Federal Regulations (2010). Titl e 10 Energy, Volume 3, Chapter 2 Department of Energy Part 434 Energy Code for New Commercial and Multi Family High Rise Residential Buildings. Department of Energy (DOE). (2010). Buildings Energy Data Book US Government Printing Office, Washingto n, DC. E lhajj N. (2006). Development of cost effective, energy e fficient steel framing: T her mal performance of slit web steel wall s tuds. Upper Marlboro, MD. Enermodal, (2001) Modeling two and three dimensional heat transfer t hrough composite wall and roof a ssemblies in hourly energy simulation p rograms 1145 RP ASHRAE, Atlanta, GA r chitect rethinks the s tud. Daily Journal of Commerce Portland, OR. March 17, 2008. H oglund T. & B urstrand H. (19 98). Slotted steel studs to reduce thermal bridges in insulated w alls. Thin Walled Structures Volume 32, Number 1, September 1998 pp. 81 109(29) H ugens P. & M ipenz B E. (2010). Thermal performance comparisons of timber stud and steel w alls. Green Being for Sustainable Building. August 2010.

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128 K osny J. & C hristian J. E. (1995). Thermal evaluation of several configurations of insulation and structural materials for some metal stud w alls. Energy and Buildings, 22 157 163. K osny J. & C hristian J. E. (1997). Metal stud wall systems: Thermal disaster, or modern wall systems with highly efficient thermal i nsulation? ASTM. Insulation Materials, Testing and Application, v. 3, 1997. K osny J. & Y arbrough D. (1998). Steel framed buildings: Impact s of wall detail configurations on the whole wall thermal p erformance. ASHRAE Transactions 1998, v.104 pt 2. K osny J (2001). Steel stud walls: Breaking a thermal b ridge. Home Energy July, 2001. K osny, J & Desjarlais A. (2001). Energy performance o f s teel stud walls: Steel framing can perform as well as w ood. Roofs + Walls October, 2001. K osny J. & Kossecka E. (2002). Multi dimensional heat transfer through c omplex b uilding envelope assemblies in hourly energy simulation p rograms. Energy and Buildings, 34 445 454. K osny J. & Y arbrough D. (2007). How the same wall can have several different r values: Relations between amount of framing and overall thermal performance in wood and steel framed w alls. Thermal Performance of the Exterior Envelopes of Buildings X, proceedings of ASHRAE THERM X, Clearwater, FL. K osny J. & Y arbrough D. (2007). Nano scale insulation at work: Thermal performance of thermally bridged wood and steel structures insulated with local aerogel i nsulation Thermal Performance of the Exterior Envelopes of Buildings X, proceedings of ASHRAE THERM X Kosny, J., Bi Steady state t hermal performance evaluation of steel framed wall assembly with local foam i nsulation. ASHRAE. Kossecka, E. & Kosny J (1996). Relations between structural and dynamic t hermal characteristics of b ui lding w alls. Proceedings of 1996 International Symposium of CIB W67 Energy and Mass Flows in the Life Cycle of Buildings Vienna, 4 10 August, pp. 627 632. Kossecka E. & Kosny J. ( 1997 ) odel of a complex thermal s tructure. Journal of Thermal Insulation and Building Envelopes vol. 20, January 1997. Kossecka, E. & Kosny, J. (2002 ). Influence of insulation configuration on hea ting and cooling loads in a continuously used building. Energy and Buildings, 34 321 331. K ossecka, E. & Kosny J. (2005). Three dimensional conduction z transfer function coefficients determined from the response factors. Energy and Buildings, 37 301 310.

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129 K ossecka E. & K osny J. (2008). box testing of building envelope assemblies: A simplified p ro cedure for estimation of minimum time of the t est. Journal of Testing and Evaluation, 36 242 249. McDermott, J. F. ( Proceedings of the 3rd International Specialty Conference on Cold Formed Steel Structures University of M issouri Rolla, Nov. 1975. Mumovic, D. & Santamouris, M. (2009 ). A Handbook of Sustainable Building Design & E ngineering MPG Books, Ltd, Bodmin, England development agenda for net zero energy, high performance green bu Brien S. (2006). building envelope: Maximizing insulation e ffecti veness through careful d esign. The Construction Specifier October 2006. Petrie, T. & Childs, P. (1997). T ynd all Air Force Base: P re coating monit oring and fresh coating r esult ORNL/CON 439/V1 Oak Ridge National Laboratory. Petrie, T. & Childs, P. (1997). T ynd all Air Force Base: Long term monitoring and m odeling. ORNL/CON 439/V2 Oak Ridge National Laboratory. Straube, J. F. & Burnett, E. F. F. (2005). Building Science for Building Enclos ures Building Science Press, Westford CT. Strzepek W.R. (1990). various combinations of insulating m aterials. Insulation Materials, Testing and A pplications, ASTM/STP 1030, 1990. dge National Laboratory, in press. Syed A. M. & Kosny J. (2006). value for wood and steel framed w alls. Journal of Building Physics, 30 163 180.

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130 BIOGRAPHICAL SKETCH Brian Kevin Bennett was born in 1968 in Perry, Florida. He is the third child of Olen and Evelyn Bennett He graduated from Gainesville High School in the spring of 1986 After graduating high school Kevin attended the University of Florida until December of 1998 when he joined the US Army f or a four 4 year enlistment. Kevin was stationed in Germany and served in the Gulf War. Kevin returned to the University of Florida in August of 1991 and received his Bachelor of Science from the M.E. Rinker, Sr. School of Building Construction in Decemb er of 1994 While in the industry, Kevin worked primarily on hospitality projects but has experience in the retail, theme park, assisted living, and office sectors. During his career Kevin has worked for several general contractors and has diverse experience in both pre construction and operations. Additionally, Kevin has experience in owner and architect representation. In May of degrees in construction management. He is currently enrolled in the M.E. Rinker, Sr. School of Building Construction and is expected to graduate in the summer of 2011. Kevin is divorced and has two sons. His older son, Kyle, was born in September of 2000 and his younger son, Michael, was born in July of 2002. Kevin currently reside s in both Gainesville, Florida and Orlando, Florida.