Energy Code Compliance: Wood-Frame Buildings and the IECC Presented 4 March 2015 by Andrew Klein, P.E. Disclaimer: This presentation was developed by a third party and is not funded by WoodWorks or the Softwood Lumber Board.
Copyright Materials This presentation is protected by US and International Copyright laws. Reproduction, distribution, display and use of the presentation without written permission of the speaker is prohibited. A S Klein Engineering, PLLC 2014
The Wood Products Council is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES), Provider #G516. Credit(s) earned on completion of this course will be reported to AIA CES for AIA members. Certificates of Completion for both AIA members and non-aia members are available upon request. This course is registered with AIA CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.
Course Description This presentation focuses on the challenges of meeting 2012 International Energy Conservation Code (IECC) requirements in modern wood-frame buildings, as well as related design considerations. Topics will include the code s scope, content and significant changes since the 2009 edition. Compliance path options will also be discussed in the context of specific building systems and features.
Learning Objectives 1. Discuss the scope, purpose and requirements of the 2012 International Energy Conservation Code (IECC) to aid designers in their understanding of minimum efficiency requirements affecting energy consumption and environmental performance improvement of buildings 2. Identify significant changes between the 2009 and 2012 IECC 3. Consider the various paths of compliance with the IECC when designing a wood-frame building bridging the gap between code and application 4. Identify solutions to common design and construction issues related to energy code requirements
Purpose of the IECC Model code Developed by ICC Local governments adopt Add amendments 47 States, DC, PR & VI
Development of the IECC Model Code developed by ICC Updated on a three-year cycle Consensus process Public Development Process
IECC Climate Zones Climate Zone IECC classifies each geographic location 1-8 Based on historical: Heating and cooling climate patterns Amount of precipitation Higher CZs Northern Lower CZs Southern
Scope of the IECC The 2012 IECC is split into two sections: Residential section Commercial section Code IECC Oregon Residential 1 & 2 Family Detached Townhouses R-2, R-3 & R-4 Buildings 3 Stories above Grade R-3 Buildings Reg. under IRC
Scope of the IECC Commercial buildings containing residential occupancies Singled-out in Section C402 More stringent building envelope requirements
Application of the IECC New construction Some additions, alterations, renovations and repairs C101.4.3 lists 8 exemptions
Application of the IECC IECC regulates: Building envelope Lighting systems Mechanical systems Space-conditioning Service water heating Change in occupancy that increases fossil fuels use Addition of space conditioning to nonconditioned space Full Compliance Almost any change in occupancy or use Lighting Requirements Historic buildings are exempt (C101.4.2)
Paths of Compliance 1. Prescriptive 2. Performance 3. ASHRAE 90.1 4. Above-Code Programs Mandatory Sections Air leakage (C402.4) Mechanical (C403.2 & C404) Electrical power & lighting (C405) ASHRAE 90.1 has its own mandatory sections
Prescriptive Path Simplest for small-to-moderately sized buildings All components meet a prescribed set of requirements On an Individual basis Building envelope (C402) HVAC (C403) Water heating (C404) Lighting & electrical (C405)
Prescriptive Path 2015 IECC Section Option 1 Option 2 Option 3 C402.1.1 C402.1.2 R-value U-factor Alt. C402 Building Envelope C403 Building Mechanical Systems C404 Service Water Heating C405 Electrical Power & Lighting C406 Additional Energy Package C403.3 Simple Mandatory Provisions Building Area Method C406.2 Efficient HVAC C403.3 Complex Space-by-Space Method C406.3 Efficient Lighting Component performance alternative C406.4 Onsite Renewables
Total Building Performance Path C 4 0 7 Mandatory sections: required to be met
ASHRAE 90.1 Alternative Prescriptive and performance-based compliance paths Chapter Option 1 Option 2 5 Building Envelope Prescriptive BE BE Trade-off 6 Heating, Ventilation, and A/C 7 Service Water Heating 6.3 Simplified Approach Mandatory & Prescrip. 6.4 & 6.5 Mandatory & Prescrip. 8 Power Mandatory 9 Lighting 9.5 BA method 9.6 SbS method
Above-Code Programs C102.1.1 Alternate Means Subject to approval Full compliance & accreditation Mandatory sections are required to be met
Significant Differences: IECC vs ASHRAE IECC More Stringent: Economizers Fan Motors Add l Eff Package (C406) ASHRAE More Stringent: Prescriptive Lighting Power Limits (Section 9) HVAC Commissioning 480,000 Btu/h cooling 50,000 ft 2
Significant Differences Between Paths ASHRAE 90.1 Window-to-wall ratio up to 40% Skylight roof area up to 5% Fenestration area of S façade > E or W The 2012 IECC Window-to-wall ratio up to 30% Skylight roof area up to 3% With exceptions How wall is defined further limits IECC area
IECC: Significant Differences Between Paths 40 ft Above-Grade Wall Area 1200 ft 2 Fenestration Area: 20% 8 ft x 5 ft Total Window Area: 240 ft 2 30 ft ASHRAE: 40 ft Gross Wall Area 1600 ft 2 Fenestration Area: 15% Below Grade 10 ft
Significant Changes in the 2012 IECC Tightened thermal envelope (C402) 30% vertical fenestration area (C402.3.1) Continuous air barrier (C402.4.1) Add l efficiency package option (C406) Commissioning (C408)
Ceilings > 15 ft Significant Changes in the 2012 IECC Section C402.3.2, Minimum skylight fenestration area Directly Under Roof Enclosed spaces greater than 10,000 ft 2 of certain uses
Common Design Considerations Integrated systems and components Occupant Comfort Safety Aesthetics Overall energy performance
Building Envelope Tradeoff
Building Envelope Tradeoff
Building Envelope Tradeoff Table C402.3 Thermal performance requirements of fenestration Other than opaque doors Area-weighted average U-factors are permitted to satisfy the requirements of each product category listed Entrance doors are allowed a higher U-factor
Building Envelope Tradeoff (2015 IECC) C402.1.5 Component performance alternative. Building envelope values and fenestration areas determined in accordance with Equation 4-2 shall be permitted in lieu of compliance with the U-, F- and C-factors in Tables C402.1.3 and C402.1.4 and the maximum allowable fenestration areas in Section C402.4.1. A + B + C + D + E Zero (Equation 4-2) Where: A = Sum of the (UA Dif) values B = Sum of the (FL Dif) values C = Sum of the (CA Dif) values D = (DA UV) - (DA U Wall ), but not less than zero E = (EA US) - (EA U Roof ), but not less than zero
Building Envelope Air Leakage (C402.4) Continuous air barrier Recessed lights 2.0 cfm tested iaw ASTM E 283 Fenestration assembles IECC Table C402.4.3 Fenestration Assembly Maximum Rate (CFM/ft 2 ) Windows 0.20 Sliding Doors 0.20 Swinging Doors 0.20 Skylights w/ cond. weepage openings 0.30 Skylights all others 0.20 Curtain walls 0.06 Storefront glazing 0.06 Glazed swinging entrance doors 1.00 Revolving doors 1.00 Test Procedure AAMA/WDMA/ CSA101/I.S.2/A440 or NFRC 400 NFRC 400 or ASTM E 283 Garage doors 0.40 ANSI/DASMA 105, Rolling doors 1.00 NFRC 400, or ASTM E 283
Building Envelope Air Leakage Materials -> air permeability 0.004 cfm/ft 2 15 materials listed Assemblies -> air leakage rate 0.04 cfm/ft 2 2 assemblies listed Full building test -> air leakage rate 0.40 cfm/ft 2 ASHRAE 90.1 has similar mandatory requirements
Semi-Heated Spaces Space 2012 IECC ASHRAE 90.1 All Climate Zones Climate Zones 1 & 2 Climate Zone 3 Unconditioned < 3.4 Btu/h ft 2 Climate Zones 4 & 5 Climate Zones 6 & 7 Climate Zone 8 Semiheated n/a 3.4 Btu/h ft 2 3.4 Btu/h ft 2 3.4 Btu/h ft 2 3.4 Btu/h ft 2 3.4 Btu/h ft 2 < 5.0 Btu/h ft 2 < 10 Btu/h ft 2 < 15 Btu/h ft 2 < 20 Btu/h ft 2 < 25 Btu/h ft 2 Conditioned 3.4 Btu/h ft 2 5.0 Btu/h ft 2 10 Btu/h ft 2 15 Btu/h ft 2 20 Btu/h ft 2 25 Btu/h ft 2
Lighting Densities Amount of energy required to light a building Total power consumption of the lighting systems divided by the total floor area Mandatory in both the 2012 IECC and ASHRAE 90.1 Space-by-Space method allows tradeoffs among spaces Building Area method requires each contiguous building area type comply on its own
55 ft Lighting Densities Building Area Method Table C405.5.2(1) Total Building Area: 55 ft x 30 ft = 1650 ft 2 LPD: 1.4 w/ft 2 for Dining: cafeteria/fast food Lighting Power Allowance: 2310 watts Space-by-Space Method Table C405.5.2(2) Fast Food Dining Establishment Kitchen Area 15 ft x 35 ft Restroom Area 15 ft x 15 ft 20 ft x 15 ft Food Preparation Area: 525 ft 2 @ 1.2 w/ft 2 Restroom Area: 225 ft 2 @ 1.0 w/ft 2 Dining Area: 900 ft 2 @ 1.4 w/ft 2 Lighting Power Allowance: 2115 watts Dining Area 20 ft x 30 ft 30 ft
Onsite Renewable Energy Prescriptive Minimum ratings (C406.4): 1850 watts 0.5 watts per ft 2 cond. floor area 3% of the energy used within building Great for buildings with tenant spaces Performance Omission of energy from non-depletable sources collected on-site from annual energy cost of the proposed design Above-Code Many award credit for onsite renewable energy Examples of on-site renewable energy include: Solar PV/thermal Wind Geothermal heating/electric Biomass Biogas
Daylighting 15 ft -or- Window Head Height 2 ft Opaque Partition 5 ft in height (ASHRAE) Ceiling height (IECC)
Daylighting Minimum daylighting areas and automatic controls play a role in permitting: Increased fenestration and skylight area (C402.3.1.1/2) Increased skylight SHGCs & U-factors (C402.3.3.3/4) Requirements: 2,500 ft 2 Independent controls Dimming to 35%
Skylights Any glazing material installed < 60 degrees from horizontal Prescriptive path in the IECC 5% of the gross roof area Automatic controls 3% of the gross roof area Manual controls Section C303.1.3 default U-factors and SHGCs Table C402.3 maximum values by Climate Zone
Minimum Skylight Fenestration Area 120 ft x 100 ft space 20 ft ceilings 4 ft x 5 ft skylights 24 ft x25 ft Daylight Zone Daylight Zone: 10,800 / 12,000 = 90%
Conclusion Keeping code requirements in mind during the design phase of a building keeps options open that contribute to the aesthetics and functions of the building. Wood construction easily meets the rigorous requirements of the 2012 IECC & ASHRAE, and the Code is progressive with respect to wood construction. The proper design and construction of the building envelope is only one piece of a codecompliant and energy efficient building, however it sets the stage for the efficient performance of the building over its entire lifetime.
Questions? This concludes The American Institute of Architects Continuing Education Systems Course Andrew S. Klein, P.E. A S Klein Engineering, PLLC andrew@asklein.com asklein.com This presentation was developed by a third party and is not funded by WoodWorks or the softwood lumber check-off.