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9th Annual CNY Engineering Expo
Holiday Inn, Liverpool, NY Monday 12 November 2012
James A. D’Aloisio, P.E., SECB, LEED AP BD+C, GPRO: O&M
BUILDING STRUCTURES & THERMAL BRIDGING
Klepper, Hahn & Hyatt Structural Engineering
315.446.9201 Landscape [email protected] Building Envelope Systems
BUILDING STRUCTURES & THERMAL BRIDGING 2 OF 48
FOR THE NEXT HOUR….
Journey to the Thermal Bridge
Why consider thermal bridging?
Basics of heat transfer and thermal bridging
Thermal Bridging Solution Strategies
Geometric Separation
Intermittent Bridging Elements
Stainless Steel Bridging Elements
Nonconductive Thermal Shims
Manufactured Structural Thermal Break Assemblies
Summary, Recommendations and Questions
BUILDING STRUCTURES & THERMAL BRIDGING 4 OF 48
COMPARISON OF COSTS BETWEEN BUILDINGS
Cu
mu
lati
ve C
ost
(Cu
rre
nt
$)
Building Life (Years) 0 25 50 75 100
Conventional building
Energy efficient building
Sustainable building
Sustainable building with
revenue from excess power generation
BUILDING STRUCTURES & THERMAL BRIDGING 5 OF 48
MY JOURNEY TO THE THERMAL BRIDGE
Wall Detail ca. 1960
The area of the steel
that is bridging the
insulation is about
1% of the wall area.
What’s the reduction
in the insulation’s
R- value?
BUILDING STRUCTURES & THERMAL BRIDGING 6 OF 48
THERMAL BRIDGING….
Is conductive heat transfer through thermally
conductive materials across a building envelope
Is responsible for energy loss as well as potential
for condensation and reduced occupant comfort
Occurs with structural steel, cold formed steel,
concrete, masonry, wood, and other materials
Has not commonly been addressed by structural
engineers in the U.S. - until recently
Can be minimized if properly detailed
BUILDING STRUCTURES & THERMAL BRIDGING 7 OF 48
BASICS OF HEAT TRANSFER
Types of Heat Transfer
Conduction
Convection
Radiation
BUILDING STRUCTURES & THERMAL BRIDGING 8 OF 48
MATERIAL
(per inch)
R-Value
ft²·°F·h/Btu
U-Factor
Btu/ft²·°F·h
Silica Aerogel R-10 0.1
Expanded Polystyrene R-3.8 to R-4.2 0.26 to 0.29
Cellulose R-3.0 to 3.8 0.33 to 0.26
Hardwood (most) R-0.71 1.4
Concrete, normal weight R-0.08 12
Stainless Steel R-0.009 110
Carbon Steel R-0.0031 320
CONDUCTIVE HEAT TRANSFER
U–Factor – A material’s thermal transmission
R-Value – A material’s resistance to heat flow
R = 1 U
BUILDING STRUCTURES & THERMAL BRIDGING 9 OF 48
CONDUCTIVE HEAT TRANSFER PATHS
Series
Add up R-values along
the path of heat flow
Parallel
Heat chooses path of
least resistance
BUILDING STRUCTURES & THERMAL BRIDGING 13 OF 48
THERMAL BRIDGING AND CONDENSATION
Steel Beam
Concrete Balcony
BUILDING STRUCTURES & THERMAL BRIDGING 14 OF 48
OTHER COUNTRIES AND THERMAL BRIDGING
All European Union countries
have new energy codes
Based on limiting carbon
emissions of buildings for
Kyoto Protocol
Set limits of thermal bridging,
varying with building types
BUILDING STRUCTURES & THERMAL BRIDGING 15 OF 48
MODERN STEEL CONSTRUCTION INSERT -
THERMAL STEEL BRIDGING
Thermal Steel Bridging
Task Committee
A joint venture between ASCE’s
Structural Engineering Institute
and AISC
BUILDING STRUCTURES & THERMAL BRIDGING 16 OF 48
COLD-FORMED STEEL FRAMING
Use continuous rigid
insulation past studs
BUILDING STRUCTURES & THERMAL BRIDGING 18 OF 48
GEOMETRIC SEPARATION
Original Detail Modified Detail
BUILDING STRUCTURES & THERMAL BRIDGING 19 OF 48
GEOMETRIC SEPARATION
Original Detail Modified Detail
BUILDING STRUCTURES & THERMAL BRIDGING 20 OF 48
GEOMETRIC SEPARATION
Reduce or eliminate
penetrations through
insulated building
envelope
BUILDING STRUCTURES & THERMAL BRIDGING 21 OF 48
INTERMITTENT BUILDING ELEMENTS
Original Detail:
Continuous angle
supporting wood
roof blocking
Modified Detail:
Clip angle, 6”
long, 24” o.c.
supporting wood
roof blocking
BUILDING STRUCTURES & THERMAL BRIDGING 22 OF 48
INTERMITTENT BUILDING ELEMENTS
Original Detail Modified Detail
BUILDING STRUCTURES & THERMAL BRIDGING 23 OF 48
INTERMITTENT BUILDING ELEMENTS
New concept
for brick shelf
angle support
BUILDING STRUCTURES & THERMAL BRIDGING 24 OF 48
STAINLESS STEEL BRIDGING ELEMENTS
Original Detail Modified Detail
BUILDING STRUCTURES & THERMAL BRIDGING 25 OF 48
STAINLESS STEEL BRIDGING ELEMENTS
Original Detail Modified Detail
BUILDING STRUCTURES & THERMAL BRIDGING 26 OF 48
STAINLESS STEEL BRIDGING ELEMENTS
Proprietary
system for
brick shelf
angle support
Comes in both
galvanized &
stainless steel
BUILDING STRUCTURES & THERMAL BRIDGING 27 OF 48
NONCONDUCTIVE THERMAL SHIMS
Original Detail:
Base plate of
steel post in
contact with
interior steel
support beam
Modified Detail:
½” thermoplastic
shim plate
between base
plate and beam
BUILDING STRUCTURES & THERMAL BRIDGING 28 OF 48
NONCONDUCTIVE THERMAL SHIMS
Original Detail Modified Detail
BUILDING STRUCTURES & THERMAL BRIDGING 29 OF 48
NONCONDUCTIVE THERMAL SHIMS
High School, Upstate NY
Only supporting 24
inches of brick
BUILDING STRUCTURES & THERMAL BRIDGING 30 OF 48
MANUFACTURED STRUCTURAL
THERMAL BREAK ASSEMBLIES (MSTBA’S)
Original Detail:
Steel cantilever
beam attached
directly to interior
steel support
Modified Detail:
MSTBA between
cantilever beam
and interior steel
support
BUILDING STRUCTURES & THERMAL BRIDGING 31 OF 48
MANUFACTURED STRUCTURAL
THERMAL BREAK ASSEMBLIES (MSTBA’S)
Original Detail Modified Detail
BUILDING STRUCTURES & THERMAL BRIDGING 32 OF 48
MANUFACTURED STRUCTURAL
THERMAL BREAK ASSEMBLIES (MSTBA’S)
Outside
Temperature
-10°C
+14°F
Outside
Temperature
-10°C
+14 F
+20°C
+68 ° F
+20°C
+68 °F
Room
Temperature
+15.1°C
+59.2° F
Room
Temperature
+10.6°C
+51.9°F
BELOW
DEW
POINT!
Without Thermal Break Thermal Break Technology
68
61
54
46
40
32
25
18
10
3
-4
Grad F
Dew point < 55°F
13°C
BUILDING STRUCTURES & THERMAL BRIDGING 33 OF 48
MANUFACTURED STRUCTURAL
THERMAL BREAK ASSEMBLIES (MSTBA’S)
Concrete
to Concrete
Steel to Steel
BUILDING STRUCTURES & THERMAL BRIDGING 39 OF 48
STEEL-TO-STEEL MSTBA’S
Tension
Insulation Spacer
Compression + Shear
BUILDING STRUCTURES & THERMAL BRIDGING 42 OF 48
NORTH AMERICAN CASE STUDIES - MSTBA’S
UNIVERSITY OF CALGARY STUDENT RESIDENCE
BUILDING STRUCTURES & THERMAL BRIDGING 43 OF 48
NORTH AMERICAN CASE STUDIES - MSTBA’S
INDIANAPOLIS
MUSEUM OF
ART - PAVILION
BUILDING STRUCTURES & THERMAL BRIDGING 44 OF 48
NORTH AMERICAN CASE STUDIES - MSTBA’S
SYRACUSE UNIVERSITY
MANLEY FIELDHOUSE
ICE STORAGE ADDITION - 2012
BUILDING STRUCTURES & THERMAL BRIDGING 46 OF 48
RECOMMENDATIONS
Minimize cross-sectional area of bridging elements, where structurally possible
Minimize conditions of continuous bridging, substituting intermittent bridges
Use stainless steel when feasible
Work with architects to develop envelope details
Consider currently available and reliable products
Look for upcoming new information and research
Consider thermal bridging in your design practice
BUILDING STRUCTURES & THERMAL BRIDGING 47 OF 48
WHAT’S AHEAD?
Research on steel connection assemblies with FRP “shims” – sponsored by Pankow Foundation, AISC, FRP manufacturers
More product info from MSTBA manufacturers
Improved energy modeling and envelope requirements in building codes, including IgCC
Awareness of carbon emissions and GWP gases?
More practitioner info - Thermal Bridging Task Committee to develop detailing guidebook
Increased practitioner awareness and experience
BUILDING STRUCTURES & THERMAL BRIDGING 48 OF 48
QUIZ
1 - Name three strategies to minimize thermal
bridging in buildings.
2 - Put in order of decreasing thermal
conductivity the following three materials:
Carbon steel, aluminum, stainless steel.
3 - Name three problems that thermal
bridging in buildings can cause.
Thank you for listening! Questions?
BUILDING STRUCTURES & THERMAL BRIDGING
Klepper, Hahn & Hyatt Structural Engineering
315.446.9201 Landscape [email protected] Building Envelope Systems
CNY Engineering Expo Monday 12 November 2012
James A. D’Aloisio, P.E., SECB, LEED AP BD+C, GPRO: O&M