Building enclosure design presentation 1
- 1. Enclosure Design Training AIA Portland August 2016 Martin Houston AIA, CSI, LEED AP Walsh Construction Co. CLEAResult Energy Trust of Oregon
- 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. Presentation Outline • Definitions • Control Layers • The Thermal Control Layer • The Air Control Layer 3
- 4. Definition: Water Vapor Water in it’s gaseous state 4
- 5. Definition: Water Vapor Water in it’s gaseous state 5
- 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. 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. 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. 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. 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. 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. The Path to Low Energy Buildings 1 2 3 4 18 Basic Building Design Enclosure MEP On-site Renewable Energy
- 19. The Path to Low Energy Buildings 1 2 3 4 19 Basic Building Design Enclosure MEP On-site Renewable Energy Load Reduction
- 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. The Path to Low Energy Buildings 1 2 3 4 21 Basic Building Design Enclosure MEP On-site Renewable Energy Load Reduction
- 22. Enclosure – Key Attributes • Insulation • Airtightness • Optimized Glazing 22
- 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 E-W Orientation = 5%-6% Reduction in Annual Energy Use
- 25. Dwg: Building Shape 25 All contain about 8 volume units- What about surface area?
- 26. Enclosure Area to Volume Ratio
- 27. Enclosure Area to Volume Ratio
- 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 Window to Wall Ratio
- 30. Window-to-Wall Ratio Assume: Window=U-0.33, Wall=R-15
- 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. 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. 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. 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. VAPOR BARRIER AIR BARRIER WATER-RESISTIVE BARRIER WATER SHEDDING SURFACE AIR BARRIER VAPOR BARRIER WATER-RESISTIVE BARRIER WATER SHEDDING SURFACE Continuity
- 39. Continuity – A Key Principle • Lack of continuity at critical barriers may result in: – Water leakage – Air leakage – Thermal bridging – Condensation 39
- 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. 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
- 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. 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. 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 Source: State of Wisconsin Minimium Requirements for the Building Envelope
- 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. 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. 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. 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. Photo - Air Barrier 56
- 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. 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
- 61. 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
- 63. 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
- 65. 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
- 66. 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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- 68. 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
- 69. THE THERMAL BARRIER Can you say “yellow light”?
- 71. 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
- 72. Thermal Barrier Problems • Thermal Bridges • Insulation Material Selection • Insulation Installation Defects 72
- 73. 73 Get your thermal bridge on
- 75. Thermal Barrier Problems • Thermal Bridges • Insulation Material Selection • Insulation Installation Defects • Glazing Assemblies 75
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- 78. Thermal Barrier Problems • Thermal Bridges • Insulation Material Selection • Insulation Installation Defects • Glazing Assemblies 78
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- 80. Thermal Bridges • Exterior Wall Framing Members – Light gauge steel framing – Wood framing 80
- 81. R-Value Comparison 81 Source: Robert Bombino
- 82. Photo - Light Steel Frame Walls 82
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- 84. 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
- 85. Photo: Not so advanced framing…
- 86. 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
- 87. Drawing – Straube report 87
- 88. Drawing – Straube report 88
- 89. Drawing – Straube report 89 Image courtesy of Mike Williams
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- 93. Design Overview Photo Credit: Casey Braunger
- 94. Aerial View from South Image courtesy of Ankrom Moisan Architects
- 95. First Floor Plan Image courtesy of Ankrom Moisan Architects
- 96. Enclosure Assemblies Images courtesy of Ankrom Moisan Architects
- 97. Shading Elements Balconies Eyebrows Image courtesy of William Wilson Architects
- 98. HVAC Design • Highly iterative process – Design work modeling work costing analysis constructability review – Repeat… • Bidding / procurement • Coordinating the work…
- 99. 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
- 100. HVAC Design • Highly iterative process – Design work modeling work costing analysis constructability review – Repeat… • Bidding / procurement • Coordinating the work… Mechanical Penthouse
- 101. HVAC Design • 3 HRV Zones • Cook ERV serves each zone
- 102. 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
- 107. Coordination Drawing at Typical Exterior Wall to Foundation
- 112. Coordination Drawing at Typical Exterior Wall to Roof
- 123. Balcony details
- 124. Balcony details