Transcript Energy Codes - Madison Local Schools

Energy Codes and the
Building Envelope
Goal of Energy Efficient Design
Conserve
Natural
Resources
Reduce
Costs
Create Healthier
Living Spaces
Save the
Environment
Preserve
Ozone Layer
A Few Acronyms
ASHREA = American Society of Heating,
Refrigerating, and Air-Conditioning
Engineers
ICC = International Code Council
IECC = International Energy Conservation
Code
Codes, Standards, and Model Codes
Code
Standard
Model
Code
• Specifies how the building must be constructed
• Example: Indiana State Building Code
• Describes how a building should be constructed
• Example: ASHRAE
• Recommendation for a code that may be adopted by a
state or local jurisdiction
• Often adopted and modified by local jurisdictions
• Examples: IBC, IECC
Commercial Energy Usage
• Office, retail, and service buildings are the
largest consumers of energy in the United
States
• About half of this energy is consumed by
lighting
• Energy Codes and Standards set a
minimum level of energy performance with
which the building must comply
Commercial Energy Codes
Commercial energy codes apply to all
buildings EXCEPT:
• One- and two-family residential
buildings
• Multi-unit residential buildings three
stories or less in height
Energy Codes
• Codes and standards may be enforced at
the state, local, or jurisdictional level
• Voluntary Energy-Efficiency Programs
–
–
–
–
Home Energy Rating System (HERS)
ENERGY STAR
Good Cents
LEED
Commercial Energy Codes
• A few states have adopted the
most recent versions (dark
green)
• Some states have no statewide
energy code (white)
• Most have adopted an older
version of ASHRAE/IECC but
will typically update as code
requirements periodically
change
Most recent standard/model code is
ASHRAE 90.1-2007/2009 IECC
Courtesy US DOE
We’ll Look at
• ASHRAE/IESNA Standard 90.1-2007
• Chapter 5 of the IECC General
Prescriptive Approach
• Use for ≤ 40% of gross wall area in vertical
fenestration
• Use for ≤ 3% of gross roof area in skylights
2009 IECC Climate Zones
Keystone
Library
Code requirements are based on climate zones
Commercial Energy Codes
Lighting
Building Envelope
COMMERCIAL
Mechanical
Service Water
Heating
What is a Building Envelope?
• Roof/ceiling
• Exterior walls
• Vertical fenestration (glazing) and
skylights
• Lowest floor
• Slab edge
• Below grade walls
Building Envelope
Sealing
Vapor Barrier
Insulation
Fenestration
• Filling small spaces in building envelope
with a soft waterproof material
• Membrane that restricts the movement
of moisture
• Material used to reduce the transmission
of heat
• Glass used in the building envelope
Sealing Requirements
• All fenestration, openings, joints, and
seams in the building envelope must be
sealed with one of the following
– Caulk
– Gasket
– Tape
– Moisture vapor-permeable wrapping material
Insulation Requirements
Building Envelope Requirements for Climate Zone 5
Roof Insulation Requirement
Keystone Library
Insulation entirely above deck: R-20 c.i.
Where c.i. = continuous insulation
SURFACING
INSULATION
METAL DECK
STEEL
OPEN WEB
JOIST
Wall Insulation Requirement
Keystone Library
Mass wall above grade: R-11.4 c.i.
BRICK
AIR GAP
What types and
thicknesses of
insulation would
meet the code in
this application?
R-11.4 INSULATION
8” CMU
Floor Insulation Requirements
Keystone Library
Mass floor (slab-on-grade) unheated: no requirement
Note: When required, this perimeter insulation must be
placed around the exterior edge of the slab.
Accepted perimeter insulation configurations
Opaque Door Requirements
Keystone Library
• Opaque doors have < 50% glass area
• Door type
– Swinging door: U-0.700 (or less)
– Overhead door: U-0.500 (or less)
Reminder: U-Factor
The rate of heat loss
through the window
The lower the U-factor, the
less heat is lost
Reciprocal of R-value (1/R)
Fenestration
• All areas (including the frames) in the
building envelope that let in light
– Examples include windows, plastic panels,
clerestories, skylights, glass doors that are
more than one-half glass, and glass block
walls
• A skylight is a fenestration surface having
a slope of less than 60 degrees from the
horizontal plane
Fenestration Requirements
• Fenestration selection is
often strongly influenced
by energy codes
• U-Factor and Solar Heat
Gain Coefficient may be
specified in codes
Wonder Window,
Co.
Fenestration Requirements
Keystone Library
Fenestration area must be less than 40%
maximum of above grade wall area
Building Envelope Requirements for Climate Zone 5
Fenestration Requirements
Definitions
Curtain Wall – Fenestration products used to create
an external non-load bearing wall that is designed to
separate the exterior and interior environments
Storefront – A nonresidential system of doors and
windows mulled as a composite fenestration structure
that has been designed to withstand heavy use
Entrance Door – Fenestration products used for
ingress, egress, and access in nonresidential buildings,
including but not limited to, exterior entrances that utilize
latching hardware and automatic closers that contain
over 50% glass specifically designed to withstand heavy
use and possible abuse
Solar Heat Gain Coefficient
(SHGC)
The fraction of incident solar radiation
admitted through a window
Expressed as a number between 0 and 1
The lower a window's solar heat gain coefficient, the less
solar heat it transmits
Overhangs and Fenestration
Requirements
• Overhangs can
decrease requirement
for SHGC (in some
climates)
• Calculate the
Projection Factor, PF
A
PF 
B
Solar Heat Gain Coefficient
(SHGC)
• Southern climates with high cooling loads
– SHGC is more important than the U-factor in
promoting energy efficiency
– Choose lowest SHGC possible
• Northern climates with insignificant
cooling loads
– Choose highest SHGC to promote solar heat
gain during cold weather
SHGC Requirements
Keystone Project
• If
PF  0.25 : U-0.40 or less
• Otherwise: no requirement
Vestibule Requirements
A small entrance area between the outer
door and the interior door
Self Closing Doors
Vestibule
Exterior Doors
Conditioned
Space  3000 FT2
DOE
• Required at entrance leading to
spaces ≥ 3000 ft2
• Doors must have self-closing
devices
• Exceptions:
−Buildings in climate zone 1
−Doors from guest room or
dwelling
−Doors for vehicles, material
handling, and adjacent
personnel doors
Resources
Barlett, R., Halverson, M.A., & Shankle, D. L. (year). Understanding building
energy codes and standards. Publication no. PNNL-14235: U. S.
Efficient Windows Collaborative. (n.d.). Retrieved December 15, 2009, from
http://www.efficientwindows.org/
Department of Energy. (n.d). Building energy codes program. Retrieved
December 15, 2009, from http://www.energycodes.gov/implement/
International Code Council (2009). International energy conservation code and
ANSI/ASHRAE/IESNA standard 90.1 2007 energy standard for buildings
except low rise residential buildings. Country Club Hills, IL: Author.