Evaluating Moisture in Brick Masonry Walls Using WUFI and THERM By Pallavi Mantha, Steven Winter Associates, Inc

The thermal resistance provided by un-insulated brick walls (R-3 to R-5) is often insufficient for occupant thermal comfort and energy efficiency in most climates. Retrofits to brick buildings are usually conducted from the interior due to both financial and social pressure to preserve the exterior façade. This seminar will focus on the thermal and hygric behavior of brick masonry walls with interior retrofit strategies. Key inputs that affect results and a methodology to comply with failure criteria are discussed. Analysis and results from research conducted by SWA will be shared.

Transcript

1. © 2012 Steven Winter Associates, Inc. All rights reserved. Moisture in Brick Masonry Walls IBPSA NYC 2012
2. Pallavi Mantha Steven Winter Associates, Inc
3. © 2012 Steven Winter Associates, Inc. All rights reserved. BUILDING AMERICA National Labs + Research Teams • Reduce home energy use by 50% • Durable, Healthy & Comfortable Homes • Best Practice Research & Technologies PROGRAM GOALS: :
4. © 2012 Steven Winter Associates, Inc. All rights reserved. Our Research WUFI vs. ACTUAL MONITORED WALLS :Document boundary conditions :How do they perform? :Do they fail? Why? Compare:
5. © 2012 Steven Winter Associates, Inc. All rights reserved. PHASE I Establish Methodology Failure Criteria Simulations
6. © 2012 Steven Winter Associates, Inc. All rights reserved. 500 WUFI Simulations 04 Climate Zones 4, 5, 6 & 7 03 Moisture Regimes A-moist, B-dry and C-marine
7. © 2012 Steven Winter Associates, Inc. All rights reserved. 78 IECC WALLS + HYBRID INSULATION 16 R-40 & R-60 WALLS 06 BRICK WALLS WITH INTERIOR INSULATION
8. © 2012 Steven Winter Associates, Inc. All rights reserved. 78 IECC WALLS + HYBRID INSULATION 16 R-40 & R-60 WALLS 06 BRICK WALLS WITH INTERIOR INSULATION
9. © 2012 Steven Winter Associates, Inc. All rights reserved. PHASE II Monitor Wall Assemblies Calibrate Models Compare Actual vs. Simulated
10. © 2012 Steven Winter Associates, Inc. All rights reserved. OVERVIEW: SOFTWARES + STANDARDS MATERIAL PROPERTIES MODEL SET-UP FAILURE CRITERIA + COMPLIANCE
11. © 2012 Steven Winter Associates, Inc. All rights reserved. OVERVIEW: SOFTWARES + STANDARDS MATERIAL PROPERTIES MODEL SET-UP FAILURE CRITERIA + COMPLIANCE
12. © 2012 Steven Winter Associates, Inc. All rights reserved. WUFI + THERM Transient Moisture and Heat transport Model 1D, 2D, PLUS Heat Transfer Model 2D IBP + ORNL LBNL
13. © 2012 Steven Winter Associates, Inc. All rights reserved. ASHRAE STANDARD 160: SETS CRITERIA FOR • Analytical Procedures • Inputs • Evaluation and Outputs
14. © 2012 Steven Winter Associates, Inc. All rights reserved. 30-DAY RUNNING AVERAGE T = Surface Temperature RH = Surface Relative Humidity ASHRAE STANDARD 160: RH < 80% when 41 >T (oF)< 104
15. © 2012 Steven Winter Associates, Inc. All rights reserved. DOES NOT APPLY TO EXTERIOR SURFACES ASHRAE STANDARD 160: Naturally/chemically mold resistant materials may be exempt! (Case by Case)
16. © 2012 Steven Winter Associates, Inc. All rights reserved. INITIAL CONDITIONS ASHRAE STANDARD 160: 2 x 90% RH for concrete 2 x 80% RH for all other materials NEW CONSTRUCTION [NC] with wet construction materials EXISTING & NC* *with dry construction materials 90% RH for concrete 80% RH for all other materials T = 68 oF
17. © 2012 Steven Winter Associates, Inc. All rights reserved. OVERVIEW: SOFTWARES + STANDARDS MATERIAL PROPERTIES MODEL SET-UP FAILURE CRITERIA + COMPLIANCE
18. © 2012 Steven Winter Associates, Inc. All rights reserved. NEW OR OLD, GET THAT BRICK TESTED Calibrate WUFI to match tested material properties
19. © 2012 Steven Winter Associates, Inc. All rights reserved. 8 Brick Varieties 80 100 120 140 Brick Old Buff Matt Clay Brick Red Matt Clay Brick Calcium Silicate Brick Solid Brick Masonry Solid Brick Extruded Solid Brick Historical Solid Brick Hand Formed Density [lb/ft3] 0 0.2 0.4 Thermal Conductivity [Btu/h ft oF] 0 10 20 Permeability [Perm in] From WUFI Database
20. © 2012 Steven Winter Associates, Inc. All rights reserved. Face Brick Selection 80 100 120 140 Brick Old Buff Matt Clay Brick Red Matt Clay Brick Calcium Silicate Brick Solid Brick Masonry Solid Brick Extruded Solid Brick Historical Solid Brick Hand Formed Density [lb/ft3] 0 0.2 0.4 Thermal Conductivity [Btu/h ft oF] 0 10 20 Permeability [Perm in] 120.8 0.28 0.94 From WUFI Database
21. © 2012 Steven Winter Associates, Inc. All rights reserved. Fill Brick Selection 80 100 120 140 Brick Old Buff Matt Clay Brick Red Matt Clay Brick Calcium Silicate Brick Solid Brick Masonry Solid Brick Extruded Solid Brick Historical Solid Brick Hand Formed Density [lb/ft3] 0 0.2 0.4 Thermal Conductivity [Btu/h ft oF] 0 10 20 Permeability [Perm in] 103 0.34 13.5 From WUFI Database
22. © 2012 Steven Winter Associates, Inc. All rights reserved. Brick Properties 120.8 103 80 100 120 140 Red Matt Clay Brick Solid Brick Extruded Density [lb/ft3] 6% 37% 0% 20% 40% Free Saturation Wf [Vol-%] 5% 33% 0% 20% 40% Critical Saturation W90 [Vol-%] From WUFI Database Fill Brick Face Brick
23. © 2012 Steven Winter Associates, Inc. All rights reserved. OVERVIEW: SOFTWARES + STANDARDS MATERIAL PROPERTIES MODEL SET-UP FAILURE CRITERIA + COMPLIANCE
24. © 2012 Steven Winter Associates, Inc. All rights reserved. 12” thick / 3 wythe 1 Wythe Face Brick A 2 Wythes Fill Brick OUT IN + •High Density •Low Permeability •Med. Density •High Permeability B 3 Wythes Fill Brick •Med. Density •High Permeability Simulation Cases
25. © 2012 Steven Winter Associates, Inc. All rights reserved. CASE 1 Uninsulated CASE 2 1” Air + R-13 FGB CASE 3 1” SPF + R-13 FGB Simulation Cases FGB = Fiberglass Batts SPF: Spray Foam
26. © 2012 Steven Winter Associates, Inc. All rights reserved. 12” thick / 3 wythe All headers? Header and Stretcher? Which Section of The Wall to Model?
27. © 2012 Steven Winter Associates, Inc. All rights reserved. Face/ Fill Brick Fill Brick 1” Air Gap / SPF Cavity Insulation OUT Mortar Joint Interior Gyp. Class III Vapor Retarder IN
28. © 2012 Steven Winter Associates, Inc. All rights reserved. Face/ Fill Brick Fill Brick 1” Air Gap / SPF Cavity Insulation OUT Mortar Joint Interior Gyp. Class III Vapor Retarder Nashville, TN Climate: 4A ASHRAE 160 Conditions: Heat T: 70oF Cool T: 75oF ACH: 0.2 [1/h] Moisture Generation Rate: 1.3 lb/h IN
29. © 2012 Steven Winter Associates, Inc. All rights reserved. Face/ Fill Brick Fill Brick 1” Air Gap / SPF Cavity Insulation OUT Mortar Joint Interior Gyp. Class III Vapor Retarder Nashville, TN Climate: 4A ASHRAE 160 Conditions: Heat T: 70oF Cool T: 75oF ACH: 0.2 [1/h] Moisture Generation Rate: 1.3 lb/h IN Monitoring Positions
30. © 2012 Steven Winter Associates, Inc. All rights reserved. SIMULATION RUN TIME INITIAL CONDITIONS [ASHRAE 160] : 03 Years [typical] : 10 Years [to assess brick drying time] : 80% RH : 68 oF T T = Temperature RH = Relative Humidity For Existing Buildings
31. © 2012 Steven Winter Associates, Inc. All rights reserved. OVERVIEW: SOFTWARES + STANDARDS MATERIAL PROPERTIES MODEL SET-UP FAILURE CRITERIA + COMPLIANCE
32. © 2012 Steven Winter Associates, Inc. All rights reserved. How Does Interior Insulation Affect The Brick Wall? WALL TEMPERATURE DRYING CAPACITY RISK OF FAILURE DROPS DROPS RISES
33. © 2012 Steven Winter Associates, Inc. All rights reserved. Failure Criteria MOISTURE CONTENT DRYING TIME MOLD GROWTH [ASHRAE] CONDENSATION POTENTIAL FREEZE-THAW
34. © 2012 Steven Winter Associates, Inc. All rights reserved. MOLD GROWTH POTENTIAL [ASHRAE] T and RH at Potential Condensation Surfaces CONDENSATION POTENTIAL Interior Air T and RH MOISTURE CONTENT + DRYING TIME Moisture Content in Brick [ Vol-%] FAILURE CRITERIA WUFI OUTPUT FILES FROST DAMAGE T at Outer Wythe
35. © 2012 Steven Winter Associates, Inc. All rights reserved. Failure Criteria MOISTURE CONTENT DRYING TIME MOLD GROWTH [ASHRAE] CONDENSATION POTENTIAL FREEZE-THAW
36. © 2012 Steven Winter Associates, Inc. All rights reserved. Wythe 1 0 5 10 15 20 MAX. MOISTURE CONTENT 3 Fill bricks 1 Face + 2 Fill bricks Maximum Moisture Content in Vol-% 1” SPF + R-13 FGB 1” AIR + R-13 FGB UNINSULATED Wythe 2 Wythe 3 1” SPF + R-13 FGB 1” AIR + R-13 FGB UNINSULATED
37. © 2012 Steven Winter Associates, Inc. All rights reserved. Failure Criteria MOISTURE CONTENT DRYING TIME MOLD GROWTH [ASHRAE] CONDENSATION POTENTIAL FREEZE-THAW
38. © 2012 Steven Winter Associates, Inc. All rights reserved. Brick Drying Time [Years] 1 Face + 2 Fill bricks 0.0 0.5 1.0 1.5 2.0 0.0 0.5 1.0 1.5 2.0 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 Mean Moisture Content [Vol-%] Uninsulated 1” Air + FGB 1” SPF + FGB Drying Time 1 Face + 2 Fill bricks
39. © 2012 Steven Winter Associates, Inc. All rights reserved. Brick Drying Time [Years] 3 Fill bricks Mean Moisture Content [Vol-%] Uninsulated 1” Air + FGB 1” SPF + FGB Drying Time 3 Fill bricks 0 2 4 6 8 0 2 4 6 8 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022
40. © 2012 Steven Winter Associates, Inc. All rights reserved. Failure Criteria MOISTURE CONTENT DRYING TIME MOLD GROWTH [ASHRAE] CONDENSATION POTENTIAL FREEZE-THAW
41. © 2012 Steven Winter Associates, Inc. All rights reserved. 3% 45% 38% 16% 60% 44% 0% 20% 40% 60% 80% MOLD GROWTH POTENTIAL: ALL CASES 3 Fill bricks 1 Face + 2 Fill bricks ASHRAE Criteria: % Failure Over 3 Year Period 1” SPF + R-13 FGB 1” AIR + R-13 FGB UNINSULATED 1” SPF + R-13 FGB 1” AIR + R-13 FGB UNINSULATED
42. © 2012 Steven Winter Associates, Inc. All rights reserved. Failure Criteria MOISTURE CONTENT DRYING TIME MOLD GROWTH [ASHRAE] CONDENSATION POTENTIAL FREEZE-THAW
43. © 2012 Steven Winter Associates, Inc. All rights reserved. POTENTIAL CONDENSATION PLANES Uninsulated 1” Air + R-13 FGB 1” SPF + R-13 FGB
44. © 2012 Steven Winter Associates, Inc. All rights reserved. CONDENSATION BY: 01: DIFFUSION 02: AIR-LEAKAGE
45. © 2012 Steven Winter Associates, Inc. All rights reserved. CONDENSATION BY DIFFUSION 1” Air + R-13 FGB Diffusion Avg. Dew point 28 F
46. © 2012 Steven Winter Associates, Inc. All rights reserved. CONDENSATION BY AIR LEAKAGE Avg. Dew point 51 F 1” Air + R-13 FGB Air Leakage Diffusion Avg. Dew point 28 F
47. © 2012 Steven Winter Associates, Inc. All rights reserved. 2% 23% 9% 3% 27% 11% 0% 10% 20% 30% 40% 50% CONDENSATION POTENTIAL: WUFI 3 Fill bricks 1 Face + 2 Fill bricks % of 3 Years when Condensing Surface Dew Point < Interior Dew Point 1” SPF + R-13 FGB 1” AIR + R-13 FGB UNINSULATED 1” SPF + R-13 FGB 1” AIR + R-13 FGB UNINSULATED
48. © 2012 Steven Winter Associates, Inc. All rights reserved. COLD OUT WARM IN Uninsulated 1” Air + R-13 FGB 1” SPF + R-13 FGB CONDENSATION POTENTIAL: THERM
49. © 2012 Steven Winter Associates, Inc. All rights reserved. Failure Criteria MOISTURE CONTENT DRYING TIME MOLD GROWTH [ASHRAE] CONDENSATION POTENTIAL FREEZE-THAW
50. © 2012 Steven Winter Associates, Inc. All rights reserved. FREEZE-THAW DAMAGE Moisture in Brick is GREATER than Critical Moisture Content Occurs ONLY when: Critical Moisture Content [W90 ] = 90% of Free Saturation [Wf ]
51. © 2012 Steven Winter Associates, Inc. All rights reserved. Time [Years] 1 Face + 2 Fill bricks Moisture Content [lb/ft3] Temperature [oF] FREEZE-THAW DAMAGE
52. SEP 20th @ SUPERSTRUCTURES, NYC Where Should I Put My Vapor Barrier: How To Use WUFI and THERM for Hygrothermal Modeling Upcoming Seminar: bit.ly/RKeiDw SimBuild 2012 Paper: bit.ly/Phf1X0 Our Technical Report: Can’t get enough?
53. © 2012 Steven Winter Associates, Inc. All rights reserved. Thank You pmantha@swinter.com www.swinter.com