Energy Codes and the Building Envelope

1. Energy Codes and the Building Envelope

2. Goal of Energy Efficient Design

3. A Few Acronyms ASHREA = American Society of Heating, Refrigerating, and Air-Conditioning Engineers ICC = International Code Council IECC = International Energy Conservation Code

4. Codes, Standards, and Model Codes

5. 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

6. 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

7. 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

8. 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

9. 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

10. 2009 IECC Climate Zones Keystone Library Code requirements are based on climate zones

11. Commercial Energy Codes

12. What is a Building Envelope? • Roof/ceiling • Exterior walls • Vertical fenestration (glazing) and skylights • Lowest floor • Slab edge • Below grade walls

13. Building Envelope

14. 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

15. Insulation Requirements Building Envelope Requirements for Climate Zone 5

16. Roof Insulation RequirementKeystone Library Insulation entirely above deck: R-20 c.i. Where c.i. = continuous insulation SURFACING INSULATION METAL DECK STEEL OPEN WEB JOIST

17. Wall Insulation RequirementKeystone Library Mass wall above grade: R-11.4 c.i. What types and thicknesses of insulation would meet the code in this application? BRICK AIR GAP R-11.4 INSULATION 8” CMU

18. Floor Insulation RequirementsKeystone 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

19. Opaque Door RequirementsKeystone Library • Opaque doors have < 50% glass area • Door type • Swinging door: U-0.700 (or less) • Overhead door: U-0.500 (or less)

20. Reminder: U-Factor

21. 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

22. 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.

23. Fenestration RequirementsKeystone Library Fenestration area must be less than 40% maximum of above grade wall area Building Envelope Requirements for Climate Zone 5

24. Fenestration RequirementsDefinitions 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

25. Solar Heat Gain Coefficient (SHGC)

26. Overhangs and Fenestration Requirements • Overhangs can decrease requirement for SHGC (in some climates) • Calculate the Projection Factor, PF

27. 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

28. SHGC RequirementsKeystone Project • If : U-0.40 or less • Otherwise: no requirement

29. Vestibule Requirements A small entrance area between the outer door and the interior door • 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 DOE

30. 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.