performance issues related to energy retrofitting old ... · old brownstone buildings stanley d....
TRANSCRIPT
10/9/2012
1
Performance Issues Related
to Energy Retrofitting
Old Brownstone Buildings
Stanley D. Gatland II
CertainTeed Corporation
7777thththth Annual North American Passive House ConferenceAnnual North American Passive House ConferenceAnnual North American Passive House ConferenceAnnual North American Passive House ConferenceSeptember 27September 27September 27September 27----30, 2012 Denver CO30, 2012 Denver CO30, 2012 Denver CO30, 2012 Denver CO
Session Learning Objectives:
• Identify issues related to energy retrofits of old
masonry buildings
• Understand how to effectively manage air flow
• Understand the impact of energy retrofits on
indoor air quality
• Understand the concept of hygrothermal analysis
through several examples in Chicago, Illinois
7777thththth Annual North American Passive House ConferenceAnnual North American Passive House ConferenceAnnual North American Passive House ConferenceAnnual North American Passive House ConferenceSeptember 27September 27September 27September 27----30, 2012 Denver CO30, 2012 Denver CO30, 2012 Denver CO30, 2012 Denver CO
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Climate
Insulation
Air Tightness
Vapor Control
Cladding Design
Cladding
Substrate
Less Risk
Dry
Less
Less
Dynamic
Drain & Vent
Non-Absorptive
Non-Absorptive
More Risk
Wet
More
More
Restrictive
Face Sealed
Absorptive
Absorptive
Moisture Balance Risk Analysis
for Low-Energy Wall Designs
Original concept presented by Mark Williamswith Williams Building Diagnostics, Ltd
Traditional Residential Wall Assembly
• Single or double wythe masonry facades
• Masonry provides building structure
• A lot of air leakage
• Little to no insulation
• Energy retrofits are limited to the inside of the building – exterior façade is the a desired feature
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3
Visible Moisture Damage
• Condensation
and staining
• Mold, mildew and decay
• Freeze-thaw damage
• Corrosion of metals
• Visual appearance, i.e.
buckling of wood siding, efflorescence of brick and mortar, paint failure
Efflorescence of Brick Surface Due
to the Migration of Mortar Salts
Ice Damming due to Air Exfiltration
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Managing Air Flow
Three Types of Pressure Differentials
Mechanical Pressure
Wind Pressure
Stack Pressure
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Wind Effect
• Wind pressure has a significant effect on buildings and creates a high, positive pressure on the upwind side and a low, negative pressure on the downwind side
• Wind greatly influences the impact of rain on building surfaces
Wind Direction & Speed Vary with Geographic Location and Season
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Rain Load Changes with Geographic Location and Building Envelope Orientation
Weather File Analyzer Software Available
• Software is available through the U.S. Department of Energy to evaluate the impact of wind driven precipitation in many localities throughout North America
• For Weather File Analyzer software contact Oak Ridge National Laboratory
www.ornl.gov/sci/roofs+walls
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Stack Effect
Stack effect damage of brick façade at top of building
• Stack pressure occurs when atmospheric pressure differences exist between the top and bottom of a building due to temperature differences
• The stack effect causes infiltration at the bottom and exfiltration at the top of buildings during the heating season
• In warm southern climates the stack effect is lessened due to the short heating season
30 Quarts30 Quarts
100X More Moisture by Air Transport than by Diffusion100X More Moisture by Air Transport than by Diffusion
Vapor DiffusionVapor Diffusion
4 x 8 Sheet ofGypsum Board
1/3 Quart1/3 Quart
Air Transport Air Transport
1 in2 Hole
Moisture is Largest Indoor Air Contaminant!
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Mechanical Effect
• Mechanical pressure is
caused by HVAC system
pressurization
• Many systems are
designed to create a
slight positive pressure in
the building to reduce the
potential for air infiltration
Ventilation Effect
• Negative pressures due to mechanical and natural
ventilation
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Air Barrier Systems
All joints, seams and penetrations
Site-built windows, doors and skylights
Openings between windows and doors
Utility penetrations
Dropped ceilings or chases
Knee walls
Walls and ceilings separating a garage from conditioned spaces
Behind tubs and showers on exterior walls
Common walls between dwelling units
Attic access openings
Rim joist junction
Other sources of infiltration
Specific requirements for fireplaces, fenestrations & recessed lighting
2012 IECC Air Sealing Requirements
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Compartmentalize to Control Air Flow
• Isolate connecting spaces to minimize the stack effect impact
• Disconnect building spaces between:
– Foundation and occupied spaces
– Roof and occupied spaces
– Floors– Rooms– Connecting corridors
• Isolate continuous vertical paths between floors
Stairwell
Utility Shaft
Moisture Sources
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11
Construction and Ground Moisture
• Concrete requires large
amounts of water
• Concrete assemblies dry
out over years
• Use vapor barriers under
concrete slabs
• Install proper footing drainage at perimeter
• Direct rainwater run off away from the building
Residential Moisture Generation
0
20
40
60
80
100
120
Soil Wood
Storage
Unvented
Furnace
Gas
Water
Heater
Four
People
Clothes
Drying
Cooking
Cleaning
Bathing House
Plants (5)
• Pints per day
• Pints per 1000 cubic feet
• Pints per load, meal or shower
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Dangers of Moisture Storage Claddings
and Air Conditioning
• Inward vapor drive due to solar
exposure is 400x greater with
moisture storage claddings
than non-storage systems
• Air conditioning creates cold
surfaces in building cavities
with temperatures below the
dew point
• Condensation will occur on the
back side of low permeance
vapor retarders, like
polyethylene and FSK facings
Hygrothermal Analysis Examples
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• Hygrothermal analysis predicts the impact of transient heat and moisture transfer on building envelopes over time
• Used on planned construction projects and existing buildings with moisture problems
• Specialized software helps the user visualize:– Surface condensation and mold growth potential
– Wetting and drying potential of the building envelope
– Moisture content of building components
• Helps building designers evaluate potential pre-construction moisture risks
• Post-construction, helps analyze and solve moisture problems
• ANSI/ASHRAE Standard 160-2009, “Criteria for Moisture-Control Design Analysis in Buildings
Hygrothermal Analysis of Building Envelopes
Water FilmWater Film
Capillary suction, caused by water
surface tension, draws water into
porous material and tiny cracks
Create capillary breaks to
protect building materials from
absorbing moisture
CavityCavity
Water FilmWater Film
Break Capillary Flow of Moisture
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Water vapor will move from areas of high vapor pressure to areas of low vapor pressure through building materials
Water Vapor Diffusion
• Test method for determining the
water vapor permeance of
building materials
• Building codes evaluate materials
using the standard dry cup
method, aka Method A or the
Desiccant Method
• Some exterior building materials
are evaluated using the standard
wet cup method, aka Method B or
the Water Method
ASTM E 96 Water Vapor Diffusion Testing
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Water Vapor Permeanceof Common Interior Wall Materials
0.01
0.1
1
10
100
0 10 20 30 40 50 60 70 80 90 100
Mean Relative Humidity (%)
Wate
r V
ap
or
Perm
ean
ce (
perm
)
Plain Gypsum Board
Primed Gypsum Board
Painted Gypsum Board
2 mil Nylon Film
Asphalt Coated Kraft Paper
6 mil Polyethylene Film
Mean Relative Humidity (%)
Wate
r vap
or
Perm
ean
ce
(Perm
s)
0
10
20
30
40
0 20 40 60 80 100
50
60
Glass Mat Gypsum Substrate
Gypsum Sheathing BoardExterior Cement Board
Recycled Paper Board
Oriented Strand Board
15 # Felt
Brick, 5/8”
70
80
Source: Oak Ridge National Laboratory (Wilkes)
Water Vapor Permeance
of Common Exterior Wall Materials
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Vapor Retarder Requirements
• Vapor retarder should be placed at the interior
• Avoid low permeance vapor retarders, such as polyethylene film or aluminum foil in:– Climates with high summer
moisture loads– Walls with moisture storage
claddings– Walls with low permeability
exterior sheathings
• IECC requires Class I or II vapor retarder in Climate Zones 4C, 5, 6, 7 and 8
• SVR works in all North American climate zones
Vapor Retarder Categories
PermPerm
Latex Primed and Painted Gyp. Bd. – 1 & 2 Coats (3 - 35)
Latex Primed Gypsum Board - 1 Coat (22 - 66)
Plain Gypsum Board (45 - 85)
6 mil Polyethylene (0.05 - 0.06)
Asphalt Coated Kraft Paper (0.3 - 3)
2 mil polyamide film (0.8 - 36)
11
Vapor Retarder
(Class II)
Vapor Retarder
(Class II)
Vapor Barrier
(Class I )
Vapor Barrier
(Class I )
0.10.10.010.01 1010
Semi-permeable
(Class III)
Semi-permeable
(Class III) PermeablePermeable100100PermPerm
Latex Primed and Painted Gyp. Bd. – 1 & 2 Coats (3 - 35)
Latex Primed Gypsum Board - 1 Coat (22 - 66)
Plain Gypsum Board (45 - 85)
6 mil Polyethylene (0.05 - 0.06)
Asphalt Coated Kraft Paper (0.3 - 3)
2 mil polyamide film (0.8 - 36)
11
Vapor Retarder
(Class II)
Vapor Retarder
(Class II)
Vapor Barrier
(Class I )
Vapor Barrier
(Class I )
0.10.10.010.01 1010
Semi-permeable
(Class III)
Semi-permeable
(Class III) PermeablePermeable100100
Traditionally vapor retarders are defined by building codes as having a standard dry cup water vapor permeance of 1 perm or less
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ASHRAE Isothermal Planes Method
==U =U =11
RT
RT
11
11.6111.61= 0.09 Btu/hr ft2 °F= 0.09 Btu/hr ft2 °F
Thermal Resistances R
Outside Air Film 0.17
4” Brick 0.98
4” Concrete Block 0.63
2” Fiber Glass Insulation 8.70
½” Gypsum Board 0.45
Inside Air Film 0.68
Total Resistance (RT) 11.61
Thermal Resistances R
Outside Air Film 0.17
4” Brick 0.98
4” Concrete Block 0.63
2” Fiber Glass Insulation 8.70
½” Gypsum Board 0.45
Inside Air Film 0.68
Total Resistance (RT) 11.61
Outside Air Film4” Brick
4” Concrete
Block
2” Fiber Glass
Insulation
Gypsum
Board
Inside Air
Film
Double Wythe Brick Wall
with Interior Insulation Layer
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Marine 4C
Pacific NW
Marine 4C
Pacific NW
Cold & Dry
5B, 6B
Cold & Dry
5B, 6B
Mixed & Humid
3A, 4A
Mixed & Humid
3A, 4A
Hot & Humid 1A, 2A, 3AHot & Humid 1A, 2A, 3A
Cold & Humid
5A, 6A
Cold & Humid
5A, 6A
Extreme
Cold & Humid 7A
Extreme
Cold & Humid 7A
Mixed & Dry
3B, 4B
Mixed & Dry
3B, 4B
Hot & Dry 2B, 3BHot & Dry 2B, 3B
Cold & Dry
5B, 6B
Cold & Dry
5B, 6B
Extreme
Cold & Humid 7A
Extreme
Cold & Humid 7A
Original concept was developed through funding by the US Dept. of Energy’s Building America Program
Continental US Climate Zone Descriptionswith 2012 IECC Climate Zone Designations
Chicago, Illinois – Cold & Humid CZ 5A
High Density Fiberglass Board
Seasonal Wetting & Drying
Interior Brick SurfaceRelative Humidity
FiberglassBoard
Double-Wythe Brick WallChicago, Illinois
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Extruded Polystyrene
Seasonal Wetting – Limited Drying
Interior Brick SurfaceRelative Humidity
XPSBoard
Double-Wythe Brick WallChicago, Illinois
Fiberglass Board with SVR
Controlled Seasonal Wetting & Drying
Interior Brick SurfaceRelative Humidity
FiberglassBoard
Double-Wythe Brick WallChicago, Illinois
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Simple Cool Roof Analysis
Cool Roofs do the following:
• Reflect more of the sun’s energy back into the atmosphere using high solar reflectance coatings or pigments (SR > 0.70)
• Release more absorbed heat back into the atmosphere using high thermal emittance coatings or pigments (TE > 0.75)
• Keep building’s cooler by reducing roof surface temperature
• Colder surfaces mean a greater potential for surface condensation and moisture accumulation
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Cold-Humid ClimateChicago, IL
Roof Surface Comparison
• Black roof surfaces can reach peak temperatures of 190ºF on a hot, sunny summer day
• Highly reflective white surfaces can reduce peak temperatures by as much as 70ºF
White Reflective Roof
Black Roof
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Simple Cool Roof AnalysisChicago, IL
• Simple roof without an insulation layer
• White roof–SR = 0.70
–TE = 0.75
• Black roof
–SR = 0.10
–TE = 0.90
Plywood Decking Moisture Content
0
5
10
15
20
25
30
35
10/1/0
0
2/1/
01
6/1/
01
10/1
/01
2/1/
02
6/1/
02
10/1/0
2
2/1/
03
6/1/
03
10/1/0
3
Date (m/d/y)M
ois
ture
Co
nte
nt
(%)
White
Black
Simple Cool Roof AnalysisChicago, IL
• Black roof’s plywood decking moisture content peaks at 20%
• White roof’s plywood decking moisture content peaks at 30%
• Both stable wetting and drying cycles
• Very important to create air tight insulated assemblies with cool roofs
Plywood Decking Moisture Content
0
5
10
15
20
25
30
35
10/1/0
0
2/1/
01
6/1/
01
10/1
/01
2/1/
02
6/1/
02
10/1/0
2
2/1/
03
6/1/
03
10/1/0
3
Date (m/d/y)
Mo
istu
re C
on
ten
t (%
)
White
Black
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Good References
• Straube & Schumacher - Interior Insulation Retrofits of Load Bearing Masonry Walls in Cold Climates, Building Science Digest 114, Building Science Corporation, 2007
• Goldberg, Huelman & Gatland II, Universal Building Envelope Hygrothermal Performance Standard for Successful Net-Zero Energy Building Design, Buildings XI Conference, 2010
Question & Answer Session
Thank you for your attention!