1 / 18

Building Envelope

Building Envelope. Outline. Structure of the Subsection Scope & Application of BE Requirements Insulation requirements Nominal vs effective Appendix Information Airtightness requirements Simple trade-off. Structure of the Subsection. 9.36.2. Building Envelope

carson
Download Presentation

Building Envelope

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Building Envelope

  2. Outline • Structure of the Subsection • Scope & Application of BE Requirements • Insulation requirements • Nominal vseffective • Appendix Information • Airtightness requirements • Simple trade-off

  3. Structure of the Subsection • 9.36.2. Building Envelope • 9.36.2.1. Scope and Application • 9.36.2.2. Determination of Thermal Characteristics & Areas • 9.36.2.3. Determination of Areas of Wall and Fenestration • 9.36.2.4. Calculation of Thermal Resistance for Assemblies • 9.36.2.5. Continuity of Insulation • 9.36.2.6. Above Ground Assemblies • 9.36.2.7. Windows, Doors and Skylights • 9.36.2.8. Below Ground Assemblies • 9.36.2.9. Required Level of Airtightness • 9.36.2.10. Construction of Air Barrier Details • 9.36.2.11. Simple Trade-offs for Building Envelope

  4. Scope and Application • Scope & Application of Building Envelope • Addresses heat transfer and air leakage • Applies between conditioned space and unconditioned space, exterior air or ground • Applies between conditioned space and adjoining storage garage, even if storage garage is heated • Testing R-values for materials and components • Calculating wall and fenestration areas • Calculating effective thermal resistanceof assemblies

  5. Continuity of Insulation • General Requirement • Insulation shall be installed continuous • Exceptions: • Structural members • Behind recessed heaters, ducts etc (min RSI 2.93) • Behind pipes, cables etc (min. RSI 2.93) • Window-wall interface (min. insulation value of window) • Joint between the foundation wall and the floor slab • Between foundation and masonry veneer (exterior insulation) • If continuity is broken • Overlap 4 times the width of the gap • Insulate 4 times the penetration on either side

  6. Required Thermal Characteristics • Opaque assemblies • Minimum effective thermal resistance (RSI = 1/U) for • Above ground assemblies: walls, attics, floors over unheated spaces, etc. • Below ground assemblies: foundation walls, floor slabs, heated slabs etc. • Two compliance options • R-values based on mechanical ventilation (no HRV) @ 2.5 ACH • R-values based on HRV @ 2.5 ACH • Windows, doors and skylights • Manufactured fenestration components: • Maximum overall thermal transmittance (U = 1/RSI), or • Minimum Energy Rating (ER) values (not for skylights) • Prescriptive specifications for site-built windows

  7. Code Requires Effective RSI Values • Above-ground Assemblies • Example: 2 x 6 construction - 16” on center • Code minimum effective value RSI 2.93 m²°C/W (R16.6) • Appendix: nominal insulation examples RSI 3.34 m²°C/W (R19) R6.9 R19 framing 23% 77% cavity

  8. Look-up Nominal Values • Above-ground requirements • Appendix – lookup tables

  9. Look-up Nominal Values • Above-ground requirements • Appendix – lookup tables

  10. Look-up Nominal Values • Above-ground requirements • Appendix – lookup tables

  11. Look-up Nominal Values • Above-ground requirements • Appendix – lookup tables

  12. Calculation of RSI Values • Above-ground assemblies – requirements (example) • Appendix – Calculation • Formula • Methods (isothermal/parallel) • Framing percentages (wood/metal) • Material values (MNECH97,IRC,ASHRAE) • Log walls (MNECH97) framing 23% 77% cavity

  13. Windows, Doors and Skylights • U-value – requirements for windows, doors and skylights • Energy Rating (ER) – requirements for windows and doors • Storm doors exempt • Exception for • 1 front door and attic/crawl space hatches: U = 2.6 W/m²K • Garage door RSI = 1.1 m²K/W

  14. Windows, Doors and Skylights • Prescriptive alternative for site-built windows • Intended for site-constructed or site assembled windows not tested to CSA A440.2 (NAFS) • Typically in custom-built homes or for specific situations where manufactured units are not available • Requirements are not intended for curtain wall construction

  15. Airtightness • Two compliance options • Prescriptive construction details • Considering different approaches (poly, ADA, exterior sheathing) • Addressing typical penetration and junctions • Using tested assemblies • Assembly required to conform to ULC S742 Air Barrier Assemblies • Limited reference: material used does not need to comply with ULC S741 Air barrier Materials • Provide junction details (manufacturers’ instructions)

  16. Airtightness • Prescriptive compliance path • General requirements • Compliance, exemptions, cross-references (9.25.3.) • Material values, continuity, sealants • Specific Construction Details • Electrical outlets and switches • Sill plates • Window-wall interface • Overhangs • Party wall details • Chimney and duct penetrations • ICF (top of the wall to attic ceiling)

  17. Simple Trade Off • Using “A over R” approach (MNECH97) • 3 Trade-off Options: • Opaque to opaque • Transparent to transparent • Limited to trades within same orientation • Opaque to transparent • Trade reduced window area for reduced attic insulation • Intended for factory constructed houses/buildings (max FDWR 15%) • Overall Limitations • Can’t reduce walls and attic roofs below 55% of required R-value • Can’t reduce other opaque assemblies below 60% of required R-values • Can’t be applied to heated assemblies • Can’t be applied to components and assemblies already exempted areas remain same

  18. Questions? www.nationalcodes.nrc.gc.ca Thank you

More Related