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Phoenix Convention Center • Phoenix, Arizona
Air Barrier Technologies
Energy Technologies Windows and Building Envelope Technologies
Diana Hun, PhDOak Ridge National Laboratory
August 12, 2015
Energy Exchange: Federal Sustainability for the Next Decade2
Air Leakage
Accounts for 10% of energy used in buildings
Office of Energy Efficiency and Renewable Energy, Building Energy Data Book
Transportation28 Quads
Industrial30 Quads
Buildings40 Quads
Air Leakage4 Quads
US Primary Energy Consumption98 Quads
Energy Exchange: Federal Sustainability for the Next Decade3
Air Sealing in Commercial Buildings
• ~800 TBtu staged energy savings in 2030 from maximum adoption• 2.5 years staged payback
Air-Sealing Systems (C)
(R) Residential (C) Commercial
Windows and Building Envelope Research and Development: Roadmap for Emerging Technologies (DOE 2014)
Energy Exchange: Federal Sustainability for the Next Decade4
• Air barrier (ASTM E2178, E2357, E779)– Controls airflow– Degree of water vapor control varies
• Water vapor retarder (ASTM E96)– Controls water vapor flow– Class I: < 0.1 perm foil-faced isocyanurate– Class II: 0.1 < perm 1 1” extruded polystyrene– Class III: 1 < perm 10 latex paint
• Water-resistive barrier (aka weather barrier; ASTM E331) – Controls water flow
Definitions
Energy Exchange: Federal Sustainability for the Next Decade5
• Low air permeance– Varies with building code/standard
• Continuous over the entire building envelope– Seal gaps around penetrations (install before cladding)– Seal wall-to-roof joint– Seal wall-to-foundation joint
• Withstands forces during and after construction
• Durable over expected lifetime of building
Air Barrier System Requirements
Energy Exchange: Federal Sustainability for the Next Decade6
• PBS-P100: Facilities standards for the Public Buildings Service– Baseline < 2 L/s/m2 @ 75 Pa– Tier 1 < 1.25 L/s/m2 @ 75 Pa– Tier 2 < 0.75 L/s/m2 @ 75 Pa– Tier 3 < 0.5 L/s/m2 @ 75 Pa
• IECC 2012 options– Material < 0.02 L/s/m2 @ 75 Pa (ASTM E2178)
– Assembly < 0.2 L/s/m2 @ 75 Pa (ASTM E2357)
– Envelope < 2 L/s/m2 @ 75 Pa
• Army Corp of Engineers– Envelope < 1.25 L/s/m2 @ 75 Pa
Air Permeance Requirements
Blower door test (ASTM E779/E1827)
Blower door test (ASTM E779/E1827)
Blower door test (ASTM E779/E1827)
Energy Exchange: Federal Sustainability for the Next Decade7
Air Barrier Effects
Emmerich and Persily 2014
Num
ber o
f Bui
ldin
gs
0.7
>13.
9
13.9
13.2
12.5
11.8
11.1
10.49.7
9.0
8.3
7.6
6.9
6.3
5.6
4.9
4.2
3.5
2.8
2.1
1.4
Envelope Leakage at 75 Pa (L/s/m2)
Buildings with air barriers Buildings without air barriers
50
45
40
35
30
25
20
15
10
5
0
Energy Exchange: Federal Sustainability for the Next Decade8
Air Barrier Types for Commercial Buildings
Energy Exchange: Federal Sustainability for the Next Decade9
• Similarities– Can serve as air and water barrier, and drainage plane– Many manufacturers require installation training
• Differences– Material cost– Installation
• Procedure, training, workmanship skills, time, cost• Temperature• Location: interior or exterior side of wall cavity
– Vapor permeance– Thermal resistance
Overall Comparison
Energy Exchange: Federal Sustainability for the Next Decade10
• Most products have high vapor permeance (5 to 50 perms)
• Require screws with 2” caps • Joints are typically sealed with tape– Should be rolled– Priming may be required on concrete, masonry and fiber faced gypsum board
Mechanically-Fastened Membranes
Fasteners with 2” caps
Energy Exchange: Federal Sustainability for the Next Decade11
• Moderate vapor permeance (0.1 to 1 perm)
• Reduce thermal bridging when on outer side of wall cavity• Can replace the exterior sheathing• Requires screws with 2” caps • Joints are typically sealed with tape– Should be rolled
Insulating Sheathings
Foil-faced polyisocyanurate boards Extruded polystyrene boards Fasteners with 2” caps
Energy Exchange: Federal Sustainability for the Next Decade12
• Available with low and high vapor permeance (0.03 to 30 perms)
• Asphalt-based membranes require substrates to be primed – Primer must cure before membrane installation
• Some non-asphalt-based membranes do not require priming• Low temperature products available• Membrane should be rolled
Self-Adhered Membranes
Priming before installation of asphalt-based membrane Primer-less self-adhered membrane
Energy Exchange: Federal Sustainability for the Next Decade13
• Available with low and high vapor permeance (0.1 to 30 perms)
• Relatively fast installation with roller or sprayer• May require personal protective equipment• Low VOC products available• Low temperature products available• Potential concerns
– Overspray– Minimum thickness
Fluid-Applied Membranes
Energy Exchange: Federal Sustainability for the Next Decade14
Closed-cell spray polyurethane foam (SPF) • Moderate vapor permeance• Reduces thermal bridging when on outer side of wall cavity• Relatively fast installation• Installers must wear personal protective equipment• Adequate ventilation should be provided during installation• Building should not be occupied during installation• Overspray and non-uniform thickness are potential concerns
Spray-Applied Foam
Energy Exchange: Federal Sustainability for the Next Decade16
Reduce Labor and Installation Time
Installed with gun and putty knife or spreader Spray applied
Liquid Flashings
Primer-Less Self-Adhered Membranes
Energy Exchange: Federal Sustainability for the Next Decade18
• Develop suite of wall retrofit solutions• Exceed ASHRAE 90.1-2010• Suitable for masonry construction
– Common in northeast– Preserve existing façade– Interior retrofit
• 10 to 15 years payback time• Evaluations based on
– Simulations– Lab tests – Field tests
Objectives
Brick façade
2” Air gap
8” CMU
R11 fiberglass insulation between steel studs
Drywall
Energy Exchange: Federal Sustainability for the Next Decade19
Retrofit Scenarios
Solution criteria Scenario Potential retrofitCost effectiveRetain existing wall 1 2” foam board over existing wall
Semi-cost effectiveRemove existing insulation
2 6” open-cell SPF within stud cavity
3 5” closed-cell SPF within stud cavity
Energy efficientRemove existing insulation and studs
4 3.5” cellulose + 2.5” cont. cellulose
5 2” closed-cell SPF + 1.5” cont. closed-cell SPF
6 3.5” cellulose + 2” cont. closed-cell SFP
7 3.5” cellulose + 1.5” cont. closed-cell SPF
8 2.5” foam board w/ air barrier
9 2.5” foam board w/o air barrier
Energy Exchange: Federal Sustainability for the Next Decade20
Evaluation Parameters
Relevant parameters per panel of industry experts
Level of importance per panel of industry experts Data
Cost-effectiveness 35% Cost analysis
Moisture management/durability 20% Simulations
Thermal performance 18% Simulations
Air leakage 12% Literature
Disruptiveness/Constructability 9% Industry assumptions
Indoor air quality 6% Simulations
Energy Exchange: Federal Sustainability for the Next Decade21
Selected Retrofit Scenarios
Solution criteria Scenario Potential retrofitCost effectiveRetain existing wall 1 2” foam board over existing wall
Semi-cost effectiveRemove existing insulation
2 6” open-cell SPF within stud cavity
3 5” closed-cell SPF within stud cavity
Energy efficientRemove existing insulation and studs
4 3.5” cellulose + 2.5” cont. cellulose
5 2” closed-cell SPF + 1.5” cont. closed-cell SPF
6 3.5” cellulose + 2” cont. closed-cell SFP
7 3.5” cellulose + 1.5” cont. closed-cell SPF
8 2.5” foam board w/ air barrier
9 2.5” foam board w/o air barrier
Energy Exchange: Federal Sustainability for the Next Decade22
• ORNL’s Flexible Research Platform• Monitoring– Building envelope– HVAC
• Calibrated model• Retrofit– Two rooms with each of the solutions– Collect data for 1 year – Improve simulation results– Issue guidelines in April 2016
Field Evaluation
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