1. Maria Spinu, PhD, LEED AP DuPont Building Innovations Feb. 25, 2014

2. 1.Recent trends in NA energy codes and changes in wall assembly design 2.Introduction to moisture simulation tools 3.Climate specific moisture analysis using WUFI simulations I.Cold climates (cz 5-8) II.Warm-Hot Humid climates (cz 1A-4A) III.Marine climates (3C-5C) © E. I. DuPont de Nemours and Company 2013. All rights reserved

3. Section 1 Recent trends in NA energy codes and changes in wall assembly design © E. I. DuPont de Nemours and Company 2013. All rights reserved

4.  Air leakage control  Thermal Insulation  Minimize Wetting  Maximize Drying Potential Impact © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 1

5. Air Infiltration Requirements [cfm/ft 2 @ 0.3 in w.g., 75Pa] Materials (ASTM E2178) Assemblies (ASTM E2357 or E1677) Whole Building (ASTM E779) NBC (National Building Code of Canada, 1990) 0.004-- Massachusetts, Minnesota, New Hampshire, Georgia, Oregon, Washington, New York, etc… 0.004-- ASHRAE 90.1 (2010)0.0040.04-- USACE(2008); NAVFAC (2011)0.004--0.25 Washington State (2010)0.004--0.25 GSA (2010) USAF (2011)0.0040.040.40 ASHRAE189.1 (2009) IECC (2012) 0.0040.040.40 IgCC (2012)-- 0.25 or Abbreviations: ASHRAE – American Society of Heating, Refrigeration and air Conditioning Engineers; USACE - US Army Corps of Engineers; GSA - General Services Administration; NAVFAC - Naval Facilities Engineering Command; USAF- United States Air Force; IgCC – International Green Construction Code or AND or AND or © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 1

6. ● Vapor Permeable: >10 Perms 1 −The higher the Perms, the more vapor permeable the material, the higher the water vapor diffusion ● Vapor Retarders: ≤ 10 Perms ̶ Class I: 0.1 Perm or less ̶ Class II: 0.1< Perm≤ 1.0 ̶ Class III: 1.0 <Perm≤10 1 2009 /2012 International Building Code (IBC): Vapor Permeable materials must have a moisture vapor permeance rating of 10 perms or greater… using Procedure A of ASTM E96. © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 1

7. Climate Zone Min. R-Value: Non-Residential IECC Min. R-Value: Non-Residential ASHRAE 90.1 200620092012 20042007/20102013 1 R-13.0 R-13 + R-5ci R-13.0 2 R-13 + R-5ciR-13.0 R-13 + R-3.8c.i. 3 R-13.0 R-13 + R-3.8c.i. R-13 + R-7.5ciR-13.0 R-13 + R-3.8c.i. R-13 + R-5.0c.i. 4 R-13.0R-13 + R-7.5c.i. R-13.0R-13 + R-7.5c.i. 5 R-13 + R-3.8c.i. R-13 + R-7.5c.i. R-13 + R-3.8c.i. R-13 + R-7.5c.i.R-13 + R-10.0c.i. 6 R-13 + R-3.8c.i.R-13 + R-7.5c.i. R-13 + R-3.8c.i.R-13 + R-7.5c.i.R-13 + R-12.5c.i. 7 R-13 + R-7.5c.i. R-13 + R-12.5c.i. 8 R-13 + R-7.5c.i. R-13 + R-17.5c.i. c.i. = continuous insulation, uninterrupted by structural members © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 1

8. © E. I. DuPont de Nemours and Company 2013. All rights reserved

9. Source: 2009 ASHRAE Handbook-Fundamentals * 1997 ASHRAE Handbook-Fundamentals ● Mineral Wool Fiber Board ● Spray Polyurethane Foam (SPF) ● Polyisocyanurate ● EPS (Expanded Polystyrene) ● XPS (Extruded Polystyrene) © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 1

10. Non-insulated Conditioned Cavity No longer meets Energy Codes in most climates 2 Energy Codes Compliant, all climates Could meet Energy Codes (constructability/insulation thickness) 2 Except for climate zone 1, per ASHRAE 90.1-2010 Air/Water Barrier 1 Steel Framed Wall Design Vapor Barrier/Retarder* Air/Water Barrier * Climate specific code requirement © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 1

11. Section 2 Moisture simulation tools © E. I. DuPont de Nemours and Company 2013. All rights reserved

12. © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 2

13. >>1,000X 1X 100X 98% 2% 1 2 3 © E. I. DuPont de Nemours and Company 2014. All rights reserved WUFI can simulate impact of all moisture sources Dew Point analysis can only simulate impact of vapor diffusion SECTION 2

14. ● Dew Point analysis is based on vapor diffusion equations ONLY (remember, diffusion is the smallest source of moisture!) ● WUFI simulations use hourly data, not a single point ● Dew Point analysis assumes steady-state conditions (equilibrium conditions) – one point in time, while actual conditions change ● Dew Point analysis determines the dew point location in the assembly, at ONE POINT in time (coldest day of the year) ● WUFI simulations are based on vapor diffusion and liquid transport equations vs. © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 2

15. (Using Dow Software) Dew Point Temperature Actual Temperature Dew Point Location in the Wall Assembly, under equilibrium conditions © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 2

16. Construction details: e.g. orientation inclination, height, etc. Initial conditions: e.g. construction moisture Climate conditions: e.g. Temperature, RH, radiation, precipitation, wind speed & direction Material properties: e.g. Density, porosity, heat capacity, thermal conductivity, permeability http://www.ornl.gov/sci/btc/apps/moisture/ibpe_s of161.htm Developed by Fraunhofer Institute for Building Physics (IBP) and Oak Ridge National Laboratory (ORNL); coupled heat & moisture transport simulation models © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 2

17. © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 2

18. Section 3 WUFI Simulations – Climate Specific Moisture Analysis © E. I. DuPont de Nemours and Company 2013. All rights reserved

19. Same questions, climate & design specific solutions! http://www.energycodes.gov/implement/pdfs/color_map_climate_zones_Mar03.pdf © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 3

20. ●Exterior climate: Chicago, IL (cz 5A) ●Interior design parameters: 69.8 ± 1.8 o F; 50±10% RH (Medium moisture loads) ●Steel-framed, split insulation wall design: R-13 + R-7.5 ci– per IECC 2012 cz 5 ●Air /Water Barrier (WRB): 25 Perms (Vapor Permeable DuPont Tyvek WRB) ●Vapor Retarder*: Class I, II & III ●Exterior insulation: XPS, MW ●Short-wave Radiation Absorptivity for red brick (0.68) (solar driven moisture) ●Three-year simulation period Brick Exterior cladding 2” Air space/50 ACH Air & Water Barrier Vapor Retarder Code Compliant, Hybrid Wall Design * Class I, II or III Vapor Retarders required in cz 5-8 © E. I. DuPont de Nemours and Company 2014. All rights reserved Traditional Exulation ●Hybrid wall design compared with traditional and exulation walls SECTION 3

21. Class I: 0.1 perm or less Class II: 0.1 < perm ≤ 1.0 perm Class III: 1.0 < perm ≤10 perm © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 3

22. H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H Cooler Surfaces Interior Exterior Interior (Warm-humid) Exterior Cooler Surfaces Air Barrier H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H vs. © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 3

23. Climate: Chicago, IL (cz5) Wall Design: Hybrid, XPS ci GB Equilibrium Moisture Content © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 3

24. Climate: Chicago, IL (cz5) ; Wall Design: Hybrid, XPS ci Interior air Dew Point Compare steel stud ext. surface T with dew point T of exfiltration air © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 3

25. © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 3

26. Drying rates can be estimated by starting the simulation with wet exterior sheathing (e.g. 15.6 lb/ft 3 or 250 kg/m 3 ) and observing the drying curves of the wetted layer Stucco cladding Air & Water Barrier Vapor Retarder Wet Exterior GB © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 3

27. WRB: 25 & 0.1 Perms/VB 1 & 10 Perms R-13 R-7.5ci R-19 R-15 WRB: 25 Perms/ No VB © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 3

28. © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 3

29. XPS vs. MW; Chicago, IL; Hybrid Wall; 1Perm VB; Vapor Permeable WRB © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 3

30. 0.1 Perms WRB 25 Perms WRB Chicago, IL; Hybrid Wall; MW ci, 1Perm VB; 0.1Perms & 25 Perms WRB © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 3

31. © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 3

32. 10 mm airspace behind XPS, 20 ACH No airspace behind XPS, 0 ACH 3 mm (1/8”) airspace behind XPS, 20 ACH Venting behind cladding Venting would make it acceptable to use XPS c.i. Venting behind XPS XPS Chicago, 25 Perms WRB, 1 Perm VB © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 3

33. 1.8 mm = 1/16in WRB w/drainage channels allows draining and could provides some venting* * No experimental data are available at this time to confirm venting through the drainage channels of drainable WRB © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 3

34. Q1: What is the role of the beer caps on the XPS board? A1: To create an airspace between WRB/Air Barrier and the vapor impermeable insulation Board, in order to facilitate drying Q2: What else do you need in this airspace? A2: Venting! Q3: What can help create some venting in this airspace? A3: Un-taped joints for XPS or any vapor impermeable insulation board Picture: Maria Spinu Source: Joseph Lstiburek, PhD -- 2013 Summer Camp © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 3 XPS Board

35. © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 3

36. ●Exterior climate: cz 5A (Chicago, IL) ●Interior design parameters: 69.8 ± 1.8 o F; 50±10% RH (Medium moisture loads) ●CMU back-up wall: 2” MW ci ●Vapor Retarder: 10 Perms (Class III) ●Air/Water Barrier: 25 Perms & 0.1 Perms ●Short-wave Radiation Absorptivity for red brick (0.68) (solar driven moisture) ●Rainscreen wall design, 2” airspace, ventilated cladding (50ACH behind cladding) SECTION 3 Brick Wet CMU Air space WRB 10 Perms 2” MW Air & Water Barrier Vapor Barrier (25 & 0.1 Perms) © E. I. DuPont de Nemours and Company 2013. All rights reserved

37. SECTION 3 Year 1 Year 2 Year 3 0.1 Perms FA WRB 25 Perms FA WRB Chicago, IL; CMU Wall; MW ci; 0.1Perm & 25 Perms WRB; 10 Perms Vapor Retarder © E. I. DuPont de Nemours and Company 2013. All rights reserved

38. ● Moisture intrusion coupled with slow drying rates could lead to moisture damage and long term durability issues ● Drying rates are affected by: −Materials choices: need vapor permeable materials to allow drying −Venting behind cladding essential for effective drying rates −Venting behind vapor impermeable continuous insulation is also essential for drying © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 3

39. 1.Condensation Risks: What is the main risk of condensation, air leakage or vapor diffusion Vapor Retarders Class I, II or III are required by code, to minimize wintertime condensation due to vapor diffusion 2.Drying Rates: Factors affecting the drying rates Drying in cold climates require: −Vapor Permeable exterior layers (WRB, continuous insulation) −Venting behind cladding Continuous Air Barriers are critical to prevent condensation due to air leakage Vapor impermeable continuous insulation (ci): −Creates double vapor barriers leading to moisture accumulation and moisture damage −Venting behind vapor impermeable ci board is one way to allow some drying of incidental water intrusion © E. I. DuPont de Nemours and Company 2014. All rights reserved SECTION 3

41. This concludes the American Institute of Architects Continuing Education Systems Program Maria.spinu@dupont.com