Post on 02-Jul-2015
Implica(ons of the New NBC Sec(on 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
Presenta<on Outline
! New Building Enclosure Energy Efficiency Requirements Under New 2012 NBC Sec(on 9.36
! Highly Insulated Wood-‐frame Enclosure Assemblies
! Building Enclosure Design Guide for Highly-‐Insulated Wood-‐frame Buildings
! New Sec(on 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
! Prescrip(ve, Trade-‐off and Energy Modeling Paths for Compliance
! Effec(ve R-‐values vs Nominal R-‐values
New NBC Sec<on 9.36 Energy Efficiency Requirements
2010 NBC Updated in December 2012 – New Sec8on 9.36. Energy Efficiency
! Nominal R-‐values = Rated R-‐values of insula(on which do not include impacts of how they are installed ! For example R-‐20 ba\ insula(on or
R-‐10 foam insula(on ! Effec(ve R-‐values or Real R-‐values =
Calculated R-‐values of assemblies/details which include impacts of installa(on and thermal bridges ! For example nominal R-‐20 ba\s
within steel studs 16” o.c. becoming ~R-‐9 effec(ve, or in wood studs ~R-‐15
Nominal vs Effec<ve R-‐values
! Thermal bridging occurs when a conduc(ve material (e.g. aluminum, steel, concrete, wood etc.) provides a path for heat to flow around insula(on
! The bypassing “bridging” of the less conduc(ve material significantly reduces its effec(veness as an insulator
! Examples: ! Wood framing (studs, plates) in insulated wall ! Steel framing in insulated wall ! Conduc(ve cladding a\achments through insula(on
(metal girts, clips, anchors, screws etc) ! Concrete slab edge (balcony, exposed slab edge)
through a wall ! Window frames and windows themselves
Thermal Bridging
! Effec(ve R-‐values account for thermal bridges and represent actual heat flow through enclosure assemblies and details ! Heat flow finds the path of least resistance ! Dispropor(onate amount of heat flow
occurs through thermal bridges ! Ofen adding more/thicker insula(on can’t
help ! Required for almost all energy and building
code calcula(ons ! Energy code compliance has historically
focused on assembly R-‐values – however more importance is being placed on details and interfaces & thermal bridges
! Air(ghtness also as important
Why Thermal Bridging is Important
! Increased emphasis on con(nuous insula(on, higher effec(ve 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 Ra(ng (ER) Tables for Windows, Doors, Skylights
! Prescrip(ve air(ghtness requirements (no blower door yet) ! HVAC duct sealing/insula(on, minimum equipment
efficiency ! Domes(c Hot Water, minimum equipment efficiency ! Energy modeling op(on & Trade-‐off op(ons
New NBC Sec<on 9.36 Energy Efficiency Requirements
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
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 – AXc: 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
With
out a
HRV
Climate Zone
Wall -‐ Above Grade: Minimum R-‐value (IP)
Roof – Flat/Cathedral: Minimum R-‐value (IP)
Roof – AXc: 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
With
a HRV
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
NEC
B 2011
ASHR
AE 90.1-‐2010 –
Reside
n<al Building Climate
Zone Wall (Mass, Wood, Steel): Min R-‐value
Roof (AXc, 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
! Some guidance (Table A-‐9.36.2.6.(1)A provided for calcula(on of effec(ve R-‐values of some assemblies (to help transi(on from nominal R-‐values)
! Sufficient for most wood-‐frame /ICF wall assemblies
! No provisions for cladding a\achment/ thermal bridging
Guidance: Effec<ve R-‐values within NBC 9.36
Wall Assembly / Insula<on Rated R-‐value
Effec<ve Wall R-‐value **
Studs at 16”, 25% F.F.*
Studs at 24”, 22% F.F.*
2x4 w/ R-‐12 baes 10.7 -‐
2x4 w/ R-‐14 baes 11.5 -‐
2x6 w/ R-‐19 baes 15.5 16.1
2x6 w/ R-‐22 baes 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 – Effec<ve R-‐values
! Effec(ve R-‐value targets above ~R-‐17 essen(ally means that standard prac(ce of ba\ insula(on in 2x6 stud frame wall is inadequate
! Shifs code minimum baseline wall assembly to: ! Insulated/Foam Sheathing ! Sprayfoam? ! Exterior/Split Rigid Insula(on ! Double/Deep Stud ! Structurally Insulated Panels (SIPs) ! Insulated Concrete Forms (ICFs)
Beyond 2x6 Framed Walls
Insula<on Placement & Wall Design Considera<ons
Interior Insula(on
Exterior Insula(on
Split Insula(on
GeXng to Higher R-‐values – Insula<on Placement
Baseline 2x6 w/ R-‐22 ba\s = R-‐16 effec<ve
Exterior Insula(on – R-‐20 to R-‐40+ effec<ve • Constraints: cladding a\achment, wall thickness • Good for wood/steel/concrete
Deep/Double Stud– R-‐20 to R-‐40+ effec<ve • Constraints wall
thickness • Good for wood,
wasted for steel
Split Insula(on– R-‐20 to R-‐40+ effec<ve • Constraints: cladding
a\achment • Good for wood, palatable for
steel
! Insula(on outboard of structure and control layers (air/vapor/water) ! Thermal mass at interior where useful ! Excellent performance in all climate zones ! Cladding A\achment biggest source of thermal loss/bridging ! Not the panacea, can s(ll mess it up
Exterior Insulated Walls
Steel Stud Concrete Heavy Timber (CLT)
! Key Considera(ons: ! Cladding A\achment ! Wall Thickness
! Heat Control: Exterior Insula(on
! Air Control: Membrane on exterior of structure
! Vapor Control: Membrane on exterior of structure
! Water Control: Membrane on exterior of structure (possibly surface of insula(on)
Exterior Insula<on Assemblies
! Many Possible Strategies – Wide Range of Performance
Cladding Aeachment through Exterior Insula<on
Minimizing Thermal Bridging through Exterior Insula<on
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
Key Considera<ons -‐ Split Insula<on Assemblies
! Key Considera(ons: ! Exterior insula(on type ! Cladding a\achment ! Sequencing & detailing
! Heat Control: Exterior and stud space Insula(on
! Air Control: House-‐wrap adhered/sheet/liquid membrane on sheathing, sealants/tapes etc. Ofen vapor permeable
! Vapor Control: Poly or VB paint at interior, plywood/OSB sheathing
! Water Control: Rainscreen cladding*, WRB membrane, surface of insula(on
Split Insula<on Assemblies – Exterior Insula<on Selec<on
! Foam insula(ons (XPS, EPS, Polyiso, ccSPF) are vapor impermeable ! Is the vapor barrier on the wrong side? ! Does your wall have two vapor barriers? ! How much insula(on should be put outside
of the sheathing? – More the be\er, but room? ! Rigid mineral or glass fiber insula(on are
vapor permeable which can address these concerns
! Vapor permeability of WRB and air-‐barrier also important ! Risk is dependant on interior condi(ons (RH) and poten(al for
air-‐leakage, and on exterior condi(ons (rain/RH) and poten(al for water leaks
! 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 air(ghtness ! Higher risk for damage if sheathing gets wet (rainwater, air leakage,
vapor diffusion)
Double/Deep Stud Insulated
Key Considera<ons – Double Stud/Deep Stud
! Key Considera(ons: ! Air-‐sealing ! Rainwater management/detailing
! Heat Control: Double stud cavity fill insula(on(s)
! Air Control: House-‐wrap/membrane on sheathing, poly, air(ght drywall on interior, OSB/plywood at interior, tapes, sealants, sprayfoam. Air(ghtness 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.
! Energy-‐Efficient Building Enclosure Design Guide for Wood-‐frame Mul(-‐Unit Residen(al Buildings in Marine to Cold Climates
! Builds off of Previous Building Enclosure Design Guides & CMHC Best Prac(ce 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
! Chapter 1: Introduc(on ! 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 Ra(ng Systems & Green Building Programs
What is in the Guide?
! Chapter 3: Moisture, Air and Thermal Control ! Building as a System ! Climate Zones ! Interior Climate, HVAC Interac(on ! Cri(cal Barriers ! Control of Rainwater Penetra(on ! Control of Air Flow ! Controlling Condensa(on ! Construc(on Moisture ! Controlling Heat Flow and Insula(on ! Whole Building Energy Efficiency ! Computer Simula(on Considera(ons for Wood-‐frame Enclosures
What is in the Guide?
! 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?
! Air Barrier Systems (Fundamentals, Materials, Performance, tes(ng) ! Sealed Poly/Sheet Membranes ! Air(ght drywall ! Sprayfoam ! Sealed-‐Sheathing Approaches
› Unsupported sheet membranes › Supported sheet membranes with
ver(cal strapping › Sandwiched membranes behind
exterior insula(on › Self-‐Adhered and liquid applied
membranes
Air Flow Control – Air Barrier Strategies
! Control of Heat Flow ! Minimizing Conduc(ve
Losses, Minimizing Air Leakage
! Placement of Insula(on within assemblies
! Wood framing factors ! Types of insula(on,
R-‐values and typical uses ! Thermal bridging and
effec(ve R-‐values
Heat Flow Control & Insula<on
! Material selec(on & guidance
! Control Func(ons ! Cri(cal Barriers ! Effec(ve 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)
! Material selec(on & guidance
! Control Func(ons ! Cri(cal Barriers ! Effec(ve 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)
Pitched-‐Roof, Exterior Insulated Assembly
! Materials & Control Func(ons
! Cri(cal Barriers ! Effec(ve R-‐values
Low-‐Slope Conven<onal Roof Assembly
! Materials & Control Func(ons
! Cri(cal Barriers ! Effec(ve R-‐values
(Accoun(ng for tapered insula(on packages)
! 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
Detailing – Colored 2D Details
Detailing – Wall to Roof Interfaces
Detailing – 2D Window Details
Detailing – 3D Window Installa<on Sequences
! Graham Finch, MASc, P.Eng gfinch@rdhbe.com 604-‐873-‐1181
! Building Enclosure Design Guide Available from FP Innova(ons: h\p://www.fpinnova(ons.ca/ResearchProgram/AdvancedBuildingSystem/designing-‐energy-‐efficient-‐building-‐enclosures.pdf
Discussion