Moving Towards More Energy Efficient Building Enclosures - Part 9 and Beyond

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Presentation from RCIC Edmonton - Moving towards more energy efficiency building enclosures - new NBC part 9.36 and beyond

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  • Mention Net Zero Retrofit Study
  • Moving Towards More Energy Efficient Building Enclosures - Part 9 and Beyond

    1. 1. Implications of the New NBC Section 9.36 Moving Towards More Energy Efficient Wood-Frame Building Enclosures Graham Finch, MASc, P.Eng Principal, Building Science Research Engineer RDH Building Engineering Ltd. Vancouver, BC RCIC 2013 Edmonton – April 30, 2013
    2. 2. Presentation Outline New Building Enclosure Energy Efficiency Requirements Under New 2012 NBC Section 9.36 Highly Insulated Wood-frame Enclosure Assemblies Building Enclosure Design Guide for Highly- Insulated Wood-frame Buildings
    3. 3. New Section 9.36 - Whole Building Energy Efficiency Requirements for Part 9 houses Reference to NECB 2011 for other buildings (Part 3) Building Enclosure (Envelope), HVAC, Hot-Water Components Prescriptive, Trade-off and Energy Modeling Paths for Compliance Effective R-values vs Nominal R- values New NBC Section 9.36 Energy Efficiency Requirements 2010 NBC Updated in December 2012 – New Section 9.36. Energy Efficiency
    4. 4. Nominal R-values = Rated R-values of insulation which do not include impacts of how they are installed For example R-20 batt insulation or R- 10 foam insulation Effective R-values or Real R-values = Calculated R-values of assemblies/details which include impacts of installation and thermal bridges For example nominal R-20 batts within steel studs 16” o.c. becoming ~R-9 effective, or in wood studs ~R-15 Nominal vs Effective R-values
    5. 5. Thermal bridging occurs when a conductive material (e.g. aluminum, steel, concrete, wood etc.) provides a path for heat to flow around insulation The bypassing “bridging” of the less conductive material significantly reduces its effectiveness as an insulator Examples: Wood framing (studs, plates) in insulated wall Steel framing in insulated wall Conductive cladding attachments through insulation (metal girts, clips, anchors, screws etc) Concrete slab edge (balcony, exposed slab edge) through a wall Window frames and windows themselves Thermal Bridging
    6. 6. Effective R-values account for thermal bridges and represent actual heat flow through enclosure assemblies and details Heat flow finds the path of least resistance Disproportionate amount of heat flow occurs through thermal bridges Often adding more/thicker insulation can’t help Required for almost all energy and building code calculations Energy code compliance has historically focused on assembly R-values – however more importance is being placed on details and interfaces & thermal bridges Airtightness also as important Why Thermal Bridging is Important
    7. 7. Increased emphasis on continuous insulation, higher effective R-values Minimum R-value Tables for Above & Below Grade Enclosures (Walls, Roofs, Floors) – dependent on whether HRV present in house (minor tradeoff allowance) Maximum U-value (minimum R-value) & Minimum Energy Rating (ER) Tables for Windows, Doors, Skylights Prescriptive airtightness requirements (no blower door yet) HVAC duct sealing/insulation, minimum equipment efficiency Domestic Hot Water, minimum equipment efficiency Energy modeling option & Trade-off options New NBC Section 9.36 Energy Efficiency Requirements
    8. 8. New NBC/NECB Climate Zone Divisions • >7000 HDD • 6000 to 6999 HDD • 5000 to 5999 HDD • 4000 to 4999 HDD • 3000 to 3999 HDD • < 3000 HDD
    9. 9. Wall, Roof & Window Requirements for Alberta (NBC 9.36) Climate Zone Wall - Above Grade: Minimum R-value (IP) Roof – Flat/Cathedral : Minimum R- value (IP) Roof – Attic: Minimum R-value (IP) Window: Max. U- value (IP) / Min. ER 8 21.9 28.5 59.2 0.25 / 29 7B 21.9 28.5 59.2 0.25 / 29 7A 17.5 28.5 59.2 0.28 / 25 6 17.5 26.5 49.2 0.28 / 25 WithoutaHRV Climate Zone Wall - Above Grade: Minimum R-value (IP) Roof – Flat/Cathedral : Minimum R- value (IP) Roof – Attic: Minimum R-value (IP) Window: Max. U- value (IP) / Min. ER 8 17.5 28.5 59.2 0.25 / 29 7B 17.5 28.5 59.2 0.25 / 29 7A 16.9 28.5 49.2 0.28 / 25 6 16.9 26.5 49.2 0.28 / 25 WithaHRV
    10. 10. Wall, Roof & Windows (NECB 2011/ASHRAE 90.1-2010) Climate Zone Wall – Above Grade: Minimum R-value (IP) Roof – Flat or Sloped: Minimum R-value (IP) Window: Max. U- value (IP) 8 31.0 40.0 0.28 7B 27.0 35.0 0.39 7A 27.0 35.0 0.39 6 23.0 31.0 0.39 NECB2011 ASHRAE90.1-2010– ResidentialBuilding Climate Zone Wall (Mass, Wood, Steel): Min R-value Roof (Attic, Cathedral/Flat) : Min R-value Window (Alum, PVC/fiberglass) : Max. U-value 8 19.2, 27.8, 27.0 47.6, 20.8 0.45, 0.35 7B 14.1, 19.6, 23.8 37.0, 20.8 0.45, 0.35 7A 14.1, 19.6, 23.8 37.0, 20.8 0.45, 0.35 6 12.5, 19.6, 15.6 37.0, 20.8 0.55, 0.35 *7A/7B combined in ASHRAE 90.1
    11. 11. Some guidance (Table A-9.36.2.6.(1)A provided for calculation of effective R-values of some assemblies (to help transition from nominal R-values) Sufficient for most wood-frame /ICF wall assemblies No provisions for cladding attachment/ thermal bridging Guidance: Effective R-values within NBC 9.36
    12. 12. Wall Assembly / Insulation Rated R- value Effective Wall R-value ** Studs at 16”, 25% F.F.* Studs at 24”, 22% F.F.* 2x4 w/ R-12 batts 10.7 - 2x4 w/ R-14 batts 11.5 - 2x6 w/ R-19 batts 15.5 16.1 2x6 w/ R-22 batts 16.6 17.4 2x6 w/ 2pcf sprayfoam (R-5/in, R-27.5) 18.3 19.3 2x6 w/ 2pcf sprayfoam (R-6/in, R-33) 18.6 19.8 *Studs at 16” o.c.=25% total Framing Factor (F.F.) and Studs at 24” o.c. =22% total framing factor. This includes typical framing arrangements of studs, sill and top plates, window headers, corners, built-up studs etc. ** All values calculated using three-dimensional thermal modeling calibrated to hot-box testing Typical Wood-frame Wall Assemblies – Effective R-values
    13. 13. Effective R-value targets above ~R-17 essentially means that standard practice of batt insulation in 2x6 stud frame wall is inadequate Shifts code minimum baseline wall assembly to: Insulated/Foam Sheathing Sprayfoam? Exterior/Split Rigid Insulation Double/Deep Stud Structurally Insulated Panels (SIPs) Insulated Concrete Forms (ICFs) Beyond 2x6 Framed Walls
    14. 14. Insulation Placement & Wall Design Considerations Interior Insulation Exterior Insulation Split Insulation
    15. 15. Getting to Higher R-values – Insulation Placement Baseline 2x6 w/ R-22 batts = R-16 effective Exterior Insulation – R-20 to R-40+ effective • Constraints: cladding attachment, wall thickness • Good for wood/steel/concrete Deep/Double Stud– R- 20 to R-40+ effective • Constraints wall thickness • Good for wood, wasted for steel Split Insulation– R-20 to R-40+ effective • Constraints: cladding attachment • Good for wood, palatable for steel
    16. 16. Insulation outboard of structure and control layers (air/vapor/water) Thermal mass at interior where useful Excellent performance in all climate zones Cladding Attachment biggest source of thermal loss/bridging Not the panacea, can still mess it up Exterior Insulated Walls Steel Stud Concrete Heavy Timber (CLT)
    17. 17. Key Considerations: Cladding Attachment Wall Thickness Heat Control: Exterior Insulation Air Control: Membrane on exterior of structure Vapor Control: Membrane on exterior of structure Water Control: Membrane on exterior of structure (possibly surface of insulation) Exterior Insulation Assemblies
    18. 18. Many Possible Strategies – Wide Range of Performance Cladding Attachment through Exterior Insulation
    19. 19. Minimizing Thermal Bridging through Exterior Insulation Longer cladding Fasteners directly through rigid insulation (up to 2” for light claddings) Long screws through vertical strapping and rigid insulation creates truss (8”+) – short cladding fasteners into vertical strapping Rigid shear block type connection through insulation, cladding to vertical strapping
    20. 20. Key Considerations - Split Insulation Assemblies Key Considerations: Exterior insulation type Cladding attachment Sequencing & detailing Heat Control: Exterior and stud space Insulation Air Control: House-wrap adhered/sheet/liquid membrane on sheathing, sealants/tapes etc. Often vapor permeable Vapor Control: Poly or VB paint at interior, plywood/OSB sheathing Water Control: Rainscreen cladding*, WRB membrane, surface of insulation
    21. 21. Split Insulation Assemblies – Exterior Insulation Selection Foam insulations (XPS, EPS, Polyiso, ccSPF) are vapor impermeable Is the vapor barrier on the wrong side? Does your wall have two vapor barriers? How much insulation should be put outside of the sheathing? – More the better, but room? Rigid mineral or glass fiber insulation are vapor permeable which can address these concerns Vapor permeability of WRB and air-barrier also important Risk is dependant on interior conditions (RH) and potential for air-leakage, and on exterior conditions (rain/RH) and potential for water leaks
    22. 22. Double 2x4/2x6 stud, Single Deep 2x10, 2x10, I-Joist etc… Common wood-frame wall assembly in many passive houses Lends itself well to pre-fabricated wall/roof assemblies Interior service wall – greater control over interior airtightness Higher risk for damage if sheathing gets wet (rainwater, air leakage, vapor diffusion) Double/Deep Stud Insulated
    23. 23. Key Considerations – Double Stud/Deep Stud Key Considerations: Air-sealing Rainwater management/detailing Heat Control: Double stud cavity fill insulation(s) Air Control: House-wrap/membrane on sheathing, poly, airtight drywall on interior, OSB/plywood at interior, tapes, sealants, sprayfoam. Airtightness on both sides of cavity recommended Vapor Control: Poly, VB paint or OSB/plywood at interior Water Control: Rainscreen cladding*, WRB at house-wrap/membrane, flashings etc.
    24. 24. Energy-Efficient Building Enclosure Design Guide for Wood-frame Multi-Unit Residential Buildings in Marine to Cold Climates Builds off of Previous Building Enclosure Design Guides & CMHC Best Practice Guides Focus on durable and highly insulated wood-frame assemblies to meet current and upcoming energy codes Guidance for taller and alternate wood-frame structures (ie post & beam, CLT) up to 6 stories Building Enclosure Design Guidance
    25. 25. Chapter 1: Introduction Context Chapter 2: Building and Energy Codes across North America Canadian Building and Energy Code Summaries & R-value requirements US Building and Energy Code Summaries & R-value requirements Performance Rating Systems & Green Building Programs What is in the Guide?
    26. 26. Chapter 3: Moisture, Air and Thermal Control Building as a System Climate Zones Interior Climate, HVAC Interaction Critical Barriers Control of Rainwater Penetration Control of Air Flow Controlling Condensation Construction Moisture Controlling Heat Flow and Insulation Whole Building Energy Efficiency Computer Simulation Considerations for Wood-frame Enclosures What is in the Guide?
    27. 27. Chapter 4: Energy Efficient Wall and Roof Assemblies Above Grade Wall Assemblies • Split Insulated, Double Stud/Deep Stud, Exterior Insulated • Infill Walls for Concrete Frame Below Grade Wall Assemblies • Interior and Exterior Insulated Roof Assemblies • Steep Slope & Low Slope Chapter 5: Detailing 2D CAD (colored) and 3D build-sequences for various typical enclosure details Chapter 6: Further Reading & References What is in the Guide?
    28. 28. Air Barrier Systems (Fundamentals, Materials, Performance, testing) Sealed Poly/Sheet Membranes Airtight drywall Sprayfoam Sealed-Sheathing Approaches › Unsupported sheet membranes › Supported sheet membranes with vertical strapping › Sandwiched membranes behind exterior insulation › Self-Adhered and liquid applied membranes Air Flow Control – Air Barrier Strategies
    29. 29. Control of Heat Flow Minimizing Conductive Losses, Minimizing Air Leakage Placement of Insulation within assemblies Wood framing factors Types of insulation, R-values and typical uses Thermal bridging and effective R-values Heat Flow Control & Insulation
    30. 30. Material selection & guidance Control Functions Critical Barriers Effective R-value Tables Energy Efficient Walls – Split Insulated Wood framing Nominal stud- space insulation [R-value (RSI)] Exterior insulation None [R-value (RSI)] R-4 (1 inch) [R-value (RSI)] R-8 (2 inches) [R-value (RSI)] R-12 (3 inches) [R-value (RSI)] R-16 (4 inches) [R-value (RSI)] R-20 (5 inches) [R-value (RSI)] R-24 (6 inches) [R-value (RSI)] 2x4 R-12 (2.1) 10.7 (1.9) 15.0 (2.6) 18.8 (3.3) 22.5 (4.0) 26.2 (4.6) 29.7 (5.2) 33.2 (5.8) R-14 (2.5) 11.5 (2.0) 15.8 (2.8) 19.6 (3.4) 23.2 (4.1) 27.0 (4.8) 30.5 (5.4) 34.0 (6.0) 2x6 R-19 (3.3) 15.5 (2.7) 19.8 (3.5) 23.7 (4.2) 27.3 (4.8) 31.0 (5.5) 34.5 (6.1) 38.0 (6.7) R-22 (3.9) 16.6 (2.9) 21.0 (3.7) 24.8 (4.4) 28.5 (5.0) 32.2 (5.7) 35.7 (6.3) 39.2 (6.9)
    31. 31. Material selection & guidance Control Functions Critical Barriers Effective R-value Tables Energy Efficient Walls – Double Stud/Deep Stud Wood framing Nominal fill insulation [R-value/inch (RSI/cm)] Gap width between stud walls No gap [R-value (RSI)] 1-inch [R-value (RSI)] 2-inches [R-value (RSI)] 3-inches [R-value (RSI)] 4-inches [R-value (RSI)] 5-inches [R-value (RSI)] 6-inches [R-value (RSI)] Double- stud 2x4 R-3.4/inch (0.24/cm) 19.1 (3.4) 22.9 (4.0) 26.5 (4.7) 30.0 (5.3) 33.4 (5.9) 36.9 (6.5) 40.3 (7.1) R-4.0/inch (0.28/cm) 20.5 (3.6) 25.1 (4.4) 29.4 (5.2) 33.4 (5.9) 37.4 (6.6) 41.5 (7.3) 45.4 (8.0)
    32. 32. Pitched-Roof, Exterior Insulated Assembly Materials & Control Functions Critical Barriers Effective R-values
    33. 33. Low-Slope Conventional Roof Assembly Materials & Control Functions Critical Barriers Effective R-values (Accounting for tapered insulation packages)
    34. 34. 2D CAD details (colored) provided for typical details for each wall assembly type (split insulated, double stud, exterior insulated) plus some for infill walls 3D sequence details provided for window interfacing (split insulated, double stud, exterior insulated) Detailing
    35. 35. Detailing – Colored 2D Details
    36. 36. Detailing – Wall to Roof Interfaces
    37. 37. Detailing – 2D Window Details
    38. 38. Detailing – 3D Window Installation Sequences
    39. 39. Graham Finch, MASc, P.Eng gfinch@rdhbe.com 604-873-1181 Building Enclosure Design Guide Available from FP Innovations: http://www.fpinnovations.ca/ResearchProgram/Advanced BuildingSystem/designing-energy-efficient-building- enclosures.pdf Discussion

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