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Building enclosure design presentation 1

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Envelope Design Principles

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Building enclosure design presentation 1

  1. 1. Enclosure Design Training AIA Portland August 2016 Martin Houston AIA, CSI, LEED AP Walsh Construction Co. CLEAResult Energy Trust of Oregon
  2. 2. Enclosure Design Training • The role of the Building Enclosure in the creation of Low Energy Buildings • Critical Barriers (Control Layers) • The Thermal Control Layer • The Air Control Layer 2
  3. 3. Presentation Outline • Definitions • Control Layers • The Thermal Control Layer • The Air Control Layer 3
  4. 4. Definition: Water Vapor Water in it’s gaseous state 4
  5. 5. Definition: Water Vapor Water in it’s gaseous state 5
  6. 6. Definition: Water Vapor Diffusion The process by which water vapor spreads or moves through permeable materials caused by a difference in water vapor pressure. 6
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  8. 8. Definition: Vapor Permeability Permeability, rated in Perms, is a measure of the rate of transfer of water vapor through a material. The higher the number, the easier it is to pass water vapor through a material. 8
  9. 9. Vapor Permeability of Standard Building Materials 1. Polyethylene .06 2. XPS Rigid 1 3. OSB 2 4. Plywood 3.5 5. EPS Rigid 3.5 6. 15# Felt 6 7. 2 PSJTX 11 8. Tyvek CW 23 9. Cat5 18 10. Vaproshield 50/212 9
  10. 10. Definition: Condensation Condensation is the change in the phase of water from the gaseous phase into liquid droplets or solid grains . 10
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  12. 12. Definition: Dew Point • The dew point is the temperature to which a given parcel of air must be cooled, at constant barometric pressure, for water vapor to condense into water. 12
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  15. 15. Pop Quiz 1. How many of you know the difference between an air barrier, a weather resistive barrier and a vapor barrier? 2. How many materials do you need to have all three in one wall 15
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  18. 18. The Path to Low Energy Buildings 1 2 3 4 18 Basic Building Design Enclosure MEP On-site Renewable Energy
  19. 19. The Path to Low Energy Buildings 1 2 3 4 19 Basic Building Design Enclosure MEP On-site Renewable Energy Load Reduction
  20. 20. The Path to Low Energy Buildings 1 2 3 4 20 Basic Building Design Enclosure MEP On-site Renewable Energy Load Reduction Meeting loads as efficiently and cleanly as possible…
  21. 21. The Path to Low Energy Buildings 1 2 3 4 21 Basic Building Design Enclosure MEP On-site Renewable Energy Load Reduction
  22. 22. Enclosure – Key Attributes • Insulation • Airtightness • Optimized Glazing 22
  23. 23. Basic Building Design (BBD) • Low energy building design should focus first on a few basic building design concepts: – Building size & shape • As small as possible for the given program • As compact as possible for the given program, relative to climatic factors – Building orientation – Optimized glazing design 23
  24. 24. 24 E-W Orientation = 5%-6% Reduction in Annual Energy Use
  25. 25. Dwg: Building Shape 25 All contain about 8 volume units- What about surface area?
  26. 26. Enclosure Area to Volume Ratio
  27. 27. Enclosure Area to Volume Ratio
  28. 28. BBD • Optimized Glazing Design – i.e. windows sized, configured and oriented to optimize daylighting, views and solar gain – Window-to-wall ratio managed to avoid excessive heat loss while allowing for daylighting and views – Glazing systems designed to avoid excessive solar gain – i.e. glass coatings, shadings, etc. – Use well-insulated & airtight glazing systems 28
  29. 29. 29 Window to Wall Ratio
  30. 30. Window-to-Wall Ratio Assume: Window=U-0.33, Wall=R-15
  31. 31. Window-to-Wall Ratio: 10%
  32. 32. Window-to-Wall Ratio: 50%
  33. 33. Window-to-Wall Ratio: 90%
  34. 34. Critical Barriers • Water-Shedding Surface  Rain Penetration Control • Water-Resistive Barrier  Rain Penetration Control • Thermal Barrier  Thermal Control – Controls conductive and radiant heat flow • Air Barrier  Air Leakage Control – Controls air flow / convective heat flow • Vapor Barrier  Vapor Diffusion Control 34
  35. 35. Critical Barriers • Water-Shedding Surface  Rain Penetration Control • Water-Resistive Barrier  Rain Penetration Control • Thermal Barrier  Thermal Control – Controls conductive and radiant heat flow • Air Barrier  Air Leakage Control – Controls air flow / convective heat flow • Vapor Barrier  Vapor Diffusion Control 35
  36. 36. Critical Barriers Thermal Barrier Exterior Stucco Cladding Air Space Sheathing Paper Exterior Sheathing Insulated Stud Space Polyethylene Sheet Interior Gypsum Board Interior Critical Barriers: Vapor Barrier /Vapor Retarder Air Barrier Water Resistive Barrier Water Shedding Surface Exterior Interior Source: RDH Building Sciences
  37. 37. Continuity – A Key Principle • Continuous barriers are required to achieve effective thermal and moisture performance • Continuity of critical barriers must be provided, not just at field areas, but also at interface conditions – Transitions – Penetrations – Terminations 37
  38. 38. VAPOR BARRIER AIR BARRIER WATER-RESISTIVE BARRIER WATER SHEDDING SURFACE AIR BARRIER VAPOR BARRIER WATER-RESISTIVE BARRIER WATER SHEDDING SURFACE Continuity
  39. 39. Continuity – A Key Principle • Lack of continuity at critical barriers may result in: – Water leakage – Air leakage – Thermal bridging – Condensation 39
  40. 40. Continuity – A Key Principle • Lack of continuity at critical barriers may result in: – Water leakage – Air leakage – Thermal bridging – Condensation • Leading to: – Poor energy performance – Comfort problems – Durability problems 40
  41. 41. Design of Critical Barriers • Designer of the building enclosure should be able to trace the continuity of each critical barrier through the enclosure system • Begin with building sections / wall sections • Continue with foundation, wall and roof details • Ensure continuity of all five barriers 41
  42. 42. Tracing the Barriers 42
  43. 43. Thermal Barrier (TB) 43
  44. 44. Water-shedding Surface (WSS) 44
  45. 45. Water-resistive Barrier (WRB) 45
  46. 46. Air Barrier (AB) 46
  47. 47. Vapor Barrier (VB) 47
  48. 48. Durability - A Key Principle • If it doesn’t last very long, it’s not very sustainable • Selection and use of durable materials - suited to the application / exposure - is critical • Effective enclosure detailing for watertightness, airtightness and thermal resistance is essential to achieving both energy performance and long term durability 48
  49. 49. The Air Barrier • The air barrier is the system of materials that controls air leakage / convective heat flow through the building enclosure • The air barrier is not one material but instead is an integrated system of many different materials/components 49
  50. 50. The Problem of Air Leakage • Air leakage accounts for 20-40% of the heat loss through building enclosures… • Air leakage = higher energy costs • Air leakage = larger carbon footprint • Air leakage = reduced water penetration control • Air leakage = increased condensation risk • Air leakage = poor airflow control – Impacts reliability of ventilation system design 50
  51. 51. 51 Source: State of Wisconsin Minimium Requirements for the Building Envelope
  52. 52. Air Barrier - Definitions • Air barriers are defined by their air permeance • Air Barrier Association of America (ABAA) has taken lead position in developing and promulgating standards • Now incorporated in many codes - including WSEC • “Materials” – ≤ 0.04 cfm/sf @ 1.57 psf pressure differential – ASTM E 2178, Standard Test Method for Air Permeance of Building Materials 52
  53. 53. Air Barrier - Definitions • “Assemblies” – A collection of air barrier materials and air barrier components assembled together in a specific manner to create continuity (ABAA) – ≤ 0.04 cfm/sf @ 1.57 psf – ASTM E 2357, Standard Test Method for Determining Air Leakage of Air Barrier Assemblies 53
  54. 54. Air Barrier - Definitions • “System” – An air barrier system is a system of building assemblies within the building enclosure designed, installed, and integrated in such a manner as to stop the uncontrolled flow of air into and out of the building enclosure (ABAA) – A whole building air barrier is a system – ≤ 0.40 cfm/sf @ 1.57 psf – ASTM E 779, Standard Test Method for Determining Air Leakage Rates by Fan Pressurization – Alternate standard: ≤ 0.25 cfm/sf @ 1.57 psf (USACE) 54
  55. 55. Air Barrier - Materials • Exterior cladding • Sealants • Flashings (membrane flashing, metal flashing) • Windows • Doors (poor AB) • Housewraps (e.g. Tyvek) • Wall membranes (e.g. “peel & stick”) • Roof membranes • Drywall • Polyethylene sheet 55
  56. 56. Photo - Air Barrier 56
  57. 57. Air Barrier - Materials • Material selection criteria includes: – Air permeance – Vapor permeance – Water resistance (if serving as WRB also) – Cost – Constructability – Availability • Location / placement of air barrier relative to insulation location is major determinant 57
  58. 58. Air Barrier - Approaches • Interior Side – Airtight Drywall Approach – Sealed Polyethylene Approach • Exterior Side – Exterior Sheathing Approach – Sheathing Membrane Approach (“housewrap”) • Where cavity insulation approach is used • Vapor permeable 58
  59. 59. Air Barrier - Approaches • Exterior Side – Exterior Sheathing Approach – Sheathing Membrane Approach (“housewrap”) • Where cavity insulation approach is used • Vapor permeable – Sheathing Membrane Approach (“peel & stick”) • Where exterior insulation approach is used • Vapor impermeable 61
  60. 60. Air Barrier - Approaches • Exterior Side – Exterior Sheathing Approach – Sheathing Membrane Approach (“housewrap”) • Where cavity insulation approach is used • Vapor permeable – Sheathing Membrane Approach (“peel & stick”) • Where exterior insulation approach is used • Vapor impermeable – Sheathing Membrane Approach (fluid-applied) • Vapor permeability dependent on whether cavity insulation or exterior insulation approach is used 63
  61. 61. Air Barrier - Continuity • To design and construct a complete air barrier system for the building, continuity must be provided at interfaces between all materials and components… • Easier said than done! 65
  62. 62. Air Barrier - Continuity • Key Details for Air Barrier Continuity: – Wall to foundation – Roof to wall – Floor lines – Window and door perimeters – Other penetrations – Transitions between wall types – Transitions between cladding materials 66
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  64. 64. Airtightness & IAQ • Mechanical ventilation becomes increasingly important as building airtightness increases • Effectiveness - and efficiency - of ventilation system becomes more highly critical to ensuring overall building performance, including indoor air quality… – Dedicated fresh air delivery to each space – Controlled air flow between spaces – Controlled ventilation rates – Heat recovery from exhaust air 68
  65. 65. THE THERMAL BARRIER Can you say “yellow light”?
  66. 66. 70 THE THERMAL BARRIER
  67. 67. The Thermal Barrier • The thermal barrier is the system of materials that controls conductive and radiant heat flow through the building enclosure • Insulation - yes - but many other materials too… 71
  68. 68. Thermal Barrier Problems • Thermal Bridges • Insulation Material Selection • Insulation Installation Defects 72
  69. 69. 73 Get your thermal bridge on
  70. 70. 74 Thermal Bridging
  71. 71. Thermal Barrier Problems • Thermal Bridges • Insulation Material Selection • Insulation Installation Defects • Glazing Assemblies 75
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  74. 74. Thermal Barrier Problems • Thermal Bridges • Insulation Material Selection • Insulation Installation Defects • Glazing Assemblies 78
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  76. 76. Thermal Bridges • Exterior Wall Framing Members – Light gauge steel framing – Wood framing 80
  77. 77. R-Value Comparison 81 Source: Robert Bombino
  78. 78. Photo - Light Steel Frame Walls 82
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  80. 80. Thermal Bridges • Exterior Wall Framing Members – Light gauge steel framing – Wood framing • Regions of Framing “Build-up” – Exterior Wall Openings (e.g. headers, posts) – Exterior Wall Corners – Exterior Wall to Floor Intersections – Exterior Wall to Roof Intersections 84
  81. 81. Photo: Not so advanced framing…
  82. 82. Other Thermal Bridges • Window Frames (Aluminum & Steel) • Metal Subframing at Cladding Systems • Steel Ledger Angles at Cladding Systems • Projecting Slab Edges (Concrete) • Large Structural Framing Members (Steel) 86
  83. 83. Drawing – Straube report 87
  84. 84. Drawing – Straube report 88
  85. 85. Drawing – Straube report 89 Image courtesy of Mike Williams
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  89. 89. Design Overview Photo Credit: Casey Braunger
  90. 90. Aerial View from South Image courtesy of Ankrom Moisan Architects
  91. 91. First Floor Plan Image courtesy of Ankrom Moisan Architects
  92. 92. Enclosure Assemblies Images courtesy of Ankrom Moisan Architects
  93. 93. Shading Elements Balconies Eyebrows Image courtesy of William Wilson Architects
  94. 94. HVAC Design • Highly iterative process – Design work  modeling work  costing analysis  constructability review – Repeat… • Bidding / procurement • Coordinating the work…
  95. 95. HVAC Design • Highly iterative process – Design work  modeling work  costing analysis  constructability review – Repeat… • Bidding / procurement • Coordinating the work… ERV HEAT PUMP Heating & Partial Cooling Image courtesy of PAE Consulting Engineers
  96. 96. HVAC Design • Highly iterative process – Design work  modeling work  costing analysis  constructability review – Repeat… • Bidding / procurement • Coordinating the work… Mechanical Penthouse
  97. 97. HVAC Design • 3 HRV Zones • Cook ERV serves each zone
  98. 98. HVAC Design • Continuous 50cfm supply air per bedroom • Continuous exhaust at kitchen and bath • Electric cove heater in living room for user control & backup heat - Estimated at 20% of building heating load • No active cooling at apartments Image courtesy of PAE Consulting Engineers
  99. 99. R-39 R-40 R-40 R-41 R-48
  100. 100. Coordination Drawing at Typical Exterior Wall to Foundation
  101. 101. Coordination Drawing at Typical Exterior Wall to Roof
  102. 102. Balcony details
  103. 103. Balcony details

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