Professional Educational Series BSP716 USGBC # Commercial Building Science Thermal Control in Building Envelopes

Transcription

1 Professional Educational Series BSP716 USGBC # Commercial Building Science Thermal Control in Building Envelopes

2 CertainTeed Building Solutions 1.5

3 CertainTeed is a Registered Provider with the American Institute of Architects Continuing Education System. Credit earned upon completion of this program will be reported to CES records for all AIA members. Certificates of Completion for non-aia members are available upon request. This program 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 product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation. This course qualifies for HSW credit. This course qualifies for Sustainable Design credit

4 Copyright This presentation is protected by U.S. and international copyright laws. Reproduction and distribution of this presentation without written permission of the sponsor is prohibited. CertainTeed Corporation

5 Learning Objectives After completing this course you will be able to: Describe the three modes of heat transfer Understand the thermal properties of building materials Describe how to calculate the thermal performance of insulated wall assemblies Describe how to insulate different types of wall assemblies Describe ways to increase the thermal performance and moisture durability of roofing assemblies Understand the thermal performance attributes of fenestration products windows, curtain walls, and doors Understand how thermal control in building envelopes can help earn points in the LEED rating systems

6 Module 1 Introduction to Thermally Efficient Building Envelopes and the LEED Rating Systems

7 Thermally Efficient Building Envelopes Create more energy efficient buildings Create more comfortable and healthful spaces Are more durable with less maintenance

8 Energy Efficiency Guidelines for Commercial Buildings ASHRAE 90.1, Energy Standard for Buildings Except Low-Rise Residential Buildings, provides for minimum R-values and guidelines for overall building energy efficiency

9 Impacts of Buildings In the United States, buildings account for: 39% of total energy use 12% of the total water consumption 68% of the total electricity consumption 38% of the carbon dioxide emissions In addition, on average, Americans spend about 90 percent or more of their time indoors where levels of pollutants may be two to five times higher, and occasionally more than 100 times higher, than outdoor levels* *Source: Life Cycle Cost Analysis of Occupant Well-being and Productivity in LEED Offices, available at:

10 Sustainable Design Sustainable design is a technique used to create buildings that minimize negative impacts on the environment and people Sustainable buildings are designed to reduce water and energy consumption, use sustainable materials, minimize disturbance to the land and ecosystem, and to provide a comfortable and healthy environment for occupants

11 Leadership in Energy and Environmental Design (LEED) LEED NC, CS, Schools, Healthcare, and Retail (Updated 2009 standards) Prerequisites plus points = Certified points = Silver points = Gold points = Platinum

12 Energy and Atmosphere (EA) The energy performance of a building depends on its design and is a key component in green building A building s orientation, materials, construction methods, building envelope, and water efficiency as well as the heating, ventilating, and air-conditioning (HVAC) and lighting systems determine how efficiently the building uses energy The most effective way to optimize energy efficiency is to use an integrated whole-building approach The Energy and Atmosphere category in the LEED rating systems incorporates energy reduction through a holistic approach

13 EA Prerequisites Prerequisites must be met for a building to be LEED Certified EA Prerequisite 1: Fundamental Commissioning of Building Energy Systems Verify that the project s energy-related systems are installed, calibrated and perform according to the owner s project requirements, basis of design and construction documents EA Prerequisite 2: Minimum Energy Performance Establish the minimum level of energy efficiency for the proposed building and systems References ANSI/ASHRAE standard EA Prerequisite 3: Fundamental Refrigerant Management To reduce stratospheric ozone depletion References U.S. EPA Clean Air Act, Title VI, Section 608

14 Indoor Environmental Quality (IEQ) IEQ is a key component of sustainable design and green building IEQ is improved in green buildings through the use of materials that do not emit toxins, through the careful control of temperature and humidity, through improved acoustics, and through the use of daylight and views The improved IEQ of green buildings has been shown to have positive effects on occupant health and productivity

15 Module 2 Modes of Heat Transfer

16 Conductive Heat Transfer Transfer of heat between materials of different temperatures while in direct contact Thermographic Image: Conduction through a divided glazing pane

17 Convective Heat Transfer Transfer of heat due to the motion of gas or liquid over a surface 3.05e e e e e e e e e e e+02 Thermographic Image: Convective heat transfer due to liquid mixing

18 Radiative Heat Transfer Transfer of heat from one object to another due to electromagnetic waves Infrared Image of Commercial Building Complex

19 Module 3 Thermal Control and LEED Credits

20 ASHRAE According to ASHRAE, this standard specifies the combinations of indoor space environment and personal factors that will produce thermal environmental conditions acceptable to 80% or more of the occupants within a space. The environmental factors addressed are temperature, thermal radiation, humidity and air speed; the personal factors are those of activity and clothing. Visit for the full standard.

21 ASHRAE Establishes minimum requirements for the energyefficient design of buildings LEED relies extensively on the performance rating method explained in Appendix G Appendix G is an informative document for rating the energy efficiency of building designs, but it does not provide verification that the minimum requirements of the code have been met For full standard visit

22 LEED for New Construction, Retail, and Core and Shell Credits EA Prerequisite 2-Minimum Energy Performance Demonstrate a 10% improvement in the proposed building performance rating for new buildings, or a 5% improvement in the proposed building performance rating for major renovations to existing buildings, compared with the baseline building performance rating calculated with Appendix G of ASHRAE EA Credit 1-Optimized Energy Performance Demonstrate an improvement in the proposed building performance rating greater than the required percentage outlined in Prerequisite 2 IEQ Credit 7 or 7.1-Thermal Comfort-Design Design HVAC systems and the building envelope to meet the requirements of ASHRAE Standard IEQ credit 7.2-Thermal Comfort- Verification (NC and Retail Only) To provide for the assessment of building occupants thermal comfort over time Implement a thermal comfort survey of building occupants

23 LEED for Schools Credits EA Prerequisite 2- Minimum Energy Performance The project must establish an energy performance rating goal for the facility design using EPA s Target Finder rating tool Demonstrate a 10% improvement in the proposed building performance rating for new buildings, or a 5% improvement in the proposed building performance rating for major renovations to existing buildings, compared with the baseline building performance rating calculated with Appendix G of ASHRAE EA Credit 1- Optimized Energy Performance Demonstrate an improvement in the proposed building performance rating greater than the required percentage outlined in Prerequisite 2 IEQ Credit 7.1-Thermal Comfort-Design Design HVAC systems and the building envelope to meet the requirements of ASHRAE Standard For natatoriums, demonstrate compliance with the Typical Natatorium Design Conditions defined in Chapter 4 of the ASHRAE HVAC Applications Handbook,2003 edition IEQ credit 7.2- Thermal Comfort-Verification To provide for the assessment of building occupants thermal comfort over time Implement a thermal comfort survey of building occupants

24 Healthcare Credits EA Prerequisite 2- Minimum Energy Performance Demonstrate a 10% improvement in the proposed building performance rating for new buildings, or a 5% improvement in the proposed building performance rating for major renovations to existing buildings, compared with the baseline building performance rating calculated with Appendix G of ASHRAE EA Credit 1- Optimized Energy Performance Demonstrate an improvement in the proposed building performance rating greater than the required percentage outlined in Prerequisite 2 IEQ Credit 7-Thermal Comfort Design HVAC systems and the building envelope to meet the requirements of ASHRAE Standard and local codes or current 2010 FGI Guidelines for Design and Construction of Health Care Facilities Provide a permanent monitoring system to ensure building performance Implement a thermal comfort survey of building occupants

25 Module 4 Thermal Properties of Building Materials

26 Material Thermal Property Measurement ASTM C 518 Heat Flow Apparatus measures heat transfer through homogeneous materials Thermal properties, like thermal resistance, conductance and conductivity can be determined from temperature, heat flux, area and thickness data

27 Building Envelope Thermal Performance ASTM C 1363 Hot Box measures the thermal performance of building envelope assemblies Measurements include the effects of thermal bridging due to structural components, as well as insulated cavities

28 Types of Thermal Insulation Cavity insulation Fiber glass Mineral wool Cellulose Open and closed cell foam plastics Reflective insulation Radiant barriers Structural insulated panels (SIPs) Insulated Concrete Forms (ICFs) Cotton Insulating sheathings Expanded polystyrene Extruded polystyrene Polyisocyanurate Fiber glass

29 Thermal Properties of Building Materials and Systems Insulation materials and building envelope systems are characterized by their resistance to heat flow Material performance Thermal conductivity, k Thermal conductance, C Thermal resistance, R-value System performance Overall thermal resistance, R T Thermal transmittance, U-factor or U-value Material surface performance Emissivity, ε Reflectivity, ρ

30 3 ASHRAE Methods for Calculating Thermal Performance of Insulated Assemblies 1. Isothermal planes method Cross-sections have continuous, homogeneous layers 2. Parallel path flow method Cross-sections have structural and cavity areas Components have similar thermal resistance 3. Modified zone method Use with steel framed assemblies Cross-sections have structural and cavity areas Structural components are highly conductive and create thermal bridges Reference: ASHRAE Handbook of Fundamentals, Chapter 25 Thermal and Water Vapor Transmission Data

31 Calculating Heat Flow Heat flow is the rate at which heat moves from an area of higher temperature to an area of lower temperature Heat flow, Q, is calculated using the following equation: Q = U A T Where, U = Thermal transmittance (Btu / (hr ft 2 F)) A = Area (ft 2 ) T = Temperature difference through the material ( F)

32 ASHRAE Isothermal Planes Method 4 Brick Thermal Resistances R Outside Air Film Outside Air Film Brick Concrete Block Concrete Block 2 Fiber Glass Insulation 8.70 ½ Gypsum Board 0.45 Inside Air Film 0.68 Total Resistance (R T ) U = 1 1 = = R T Btu/hr ft2 2 F R T Inside Air Film Gypsum Board 2 Fiber Glass Insulation

33 ASHRAE Parallel Path Flow Method Building Element R Cavity R Frame Outside Surface (15 mph wind) /8 Stucco Building Paper ½ Exterior Gypsum Board R 13 Fiber Glass Batt x 4 Wood Stud Water-Resistive Barrier Gypsum Sheathing Wood Framing ½ Gypsum Board Inside Surface (Still Air) Thermal Resistance, R Conventional Stucco Flashing R T = (0.75 x 14.94) + (0.25 x 6.32) = Btu/(h ft 2 F) U = 1/R T = (h ft 2 F)/Btu Metal Lath Gypsum Board

34 Metal Studs Transfer More Heat Than Other Building Materials Metals conduct 300 to 1,000 times more heat than most building materials The thermal impact of a metal stud in a framed cavity is greater than the actual surface area of the stud Steel Stud Wood Stud Thermographic Image

35 ASHRAE Modified Zone Method This calculation is very complex To calculate use the free online resource available through Oak Ridge National Laboratory

36 Module 5 Exterior Walls

37 Types of Exterior Walls Concrete block Concrete tilt-up Metal building Masonry façade

38 Concrete Block & Tilt-up Walls Insulating sheathings can be installed either on the interior or on the exterior of a concrete structure Air Space Brick Tie Concrete Block Brick Facade Water Resistive Barrier/ Air Barrier Weep Hole Flashing Insulating Sheathing

39 Concrete Block & Tilt-up Walls Insulating sheathings can be installed either on the interior or on the exterior of a concrete structure Location of the sheathing depends on the climate and the type of sheathing material Stucco Plaster Water Resistive Barrier/Air Barrier Stucco Lath Concrete Block Fiber Glass Board

40 Concrete Block & Tilt-up Walls Insulating sheathings can be installed either on the interior or on the exterior of a concrete structure Location of the sheathing depends on the climate and the type of sheathing material Interior non-load bearing steel framed assemblies can support cavity insulation Many building codes have reduced insulation requirements due to the mass effect of the concrete Brick Tie Insulated Steel-Stud Cavity Wall Air Space Concrete Block Weep Hole Flashing Gypsum Board Brick Facade Water Resistive Barrier/ Air Barrier

41 Exterior Insulation & Finishing System (EIFS) Installed in place of traditional stucco Exterior gypsum board or masonry wall typical substrate Manufacturers installation instructions must be followed for successful performance Interior Gypsum Board Steel Studs Exterior Sheathing Water Resistive Barrier Drainage Mat EIFS Mechanical Fastener EIFS Insulation EIFS Base Coat EIFS Finish

42 Metal Building Insulation Installation and compliance recommendations are available online at

43 R-value/U-value of Metal Building Insulation Screw Down Roofs (5 Purlin Spacing) R-Value NAIMA (Rev. 2000) U-Value Screw Down Roof 12 Fastener Spacing U-Value Screw Down Roof 6 Fastener Spacing Insulation Side Walls (7 Girt Spacing) R-Value NAIMA (Rev. 2000) U-Value Screw Down Wall 12 Fastener Spacing U-Value Screw Down Wall 6 Fastener Spacing Insulation Vapor Retarder

44 Steel Stud Cavity Wall Recommendations Improve thermal performance and increase cavity condensation control by using: Insulating sheathings Exterior air/wind barriers Interior air barriers Smart vapor retarders Water resistive barrier (WRB) Ventilation and drainage space between masonry façade and WRB A very cost-effective combination Smart Vapor Retarder Interior Air Barrier Fiber Glass Steel Studs Gypsum Board Air Barrier Water Resistive Barrier Air Space Insulating Sheathing Weep Hole Gypsum Sheathing Brick Facade Flashing

45 Comparison of Three Walls 3 ½ inch cavity, R-13 insulation 5 ½ inch cavity, R-19 insulation 3 ½ inch cavity, R-13 insulation and R-5 insulating sheathing

46 Base Wall 3-½ Cavity Interior Drywall Gypsum Sheathing Water Resistive Barrier R-13 Fiber Glass Steel Studs Smart Vapor Retarder Air Space Wall Tie Weep Holes Flashing Brick Facade R T = 6.7 h ft 2 F/Btu

47 Improved Wall Increase Cavity Depth to 5-1/2 Interior Drywall Gypsum Sheathing Water Resistive Barrier R-19 Fiber Glass Steel Studs Smart Vapor Retarder Air Space Wall Tie Weep Holes Flashing Brick Facade R T = 8.0 h ft 2 F/Btu

48 Best Configuration 3-1/2 Cavity Interior Drywall Gypsum Sheathing Water Resistive Barrier R-13 Fiber Glass Steel Studs Smart Vapor Retarder Air Space R-5 Insulating Sheathing Flashing Weep Holes Brick Facade Wall Tie R T = 11.5 h ft 2 F/Btu

49 Module 6 Commercial Roofing

50 Types of Commercial Roofing Systems Low-sloped roof Metal roof Cool roof Wood framed shingle roof

51 Low-Sloped Roof Considerations Protect insulating sheathings from moisture penetration Use high solar reflective roofing materials to increase thermal performance Slope insulation materials toward drains Thermally isolate parapets from roof/wall intersections Flashing is critical when integrating parapets, access doors, elevator towers and penetrations A good resource for accurate roof surface radiative properties is the Cool Roof Rating Council (CRRC) at Insulating Sheathings Improve Thermal Performance Reflective Surfaces Decrease Solar Loads

52 Use Thermal Blocks over Purlins to Improve Thermal Performance of Metal Building Roofs Standing Seam Roof Single Layer (5 Purlin Spacing, 24 o.c. clip spacing, 1 x 3 foam block on purlin) Insulation NAIMA (Rev. 2000) R-Value U-Value Single Layer Note: The lower the U-value the better the performance. Thermal Block

53 Use Thermal Blocks over Purlins to Improve Thermal Performance of Metal Building Roofs Standing Seam Roof Double Layer (5 Purlin Spacing, 24 o.c. clip spacing, 1 x 3 foam block on purlin) NAIMA (Rev. 2000) R-Values U-Value 10/ / / / / / / / / / Double Layer Thermal Block 1 st Layer Insulation 2 nd Layer Insulation

54 Module 7 Fenestration Products Windows, Curtain Walls, Doors

55 Window Systems Install High Performance Windows Look for the NFRC Label

56 Window Systems Install high performance windows Look for the NFRC label Frame type Glazing type Gas Fill Low-e coatings Air Leakage Sample Window Label

57 Window Systems U-factor, like R-value, indicates thermal performance Energy Star Recommended Maximums U-factor Northern Zone Central Zone Southern Zone U-factor U-factor Lower is better Sample Window Label

58 Window Systems Solar Heat Gain Coefficient Indicates efficiency in preventing solar radiation from heating building Energy Star Recommended Maximums SHGC Northern Zone Central Zone Any 0.55 Southern Zone Lower is better 0.40 Solar Heat Gain Coefficient Solar Heat Gain Coefficient Sample Window Label

59 Fenestration Products Windows/Curtain Walls/Doors Lower U-factor means increased energy efficiency and better condensation control on surfaces Air tight systems increase energy efficiency and reduce the potential for moisture accumulation Insulate hidden mounting flanges and metal surfaces to reduce surface condensation Installation and flashing details are critical Thermally broken commercial window

60 Pay Attention to Details Don t miss insulating around ALL irregular details, like Roof/wall intersections Wall/slab intersections Balconies Parking garages Windows & doors

61 Pay Attention to Details Poor Installation Impacts Thermal Performance Avoid insulation voids, gaps and compression Infrared View insulation void near top plate

62 Course Summary We have reviewed the following topics: The three modes of heat transfer conduction, convection and radiation Thermal properties of building materials Three ASHRAE thermal performance calculation procedures Ways to insulate concrete block, concrete tilt-up, metal building and façade wall systems Ways to improve the thermal performance of commercial roofing assemblies Thermal properties of windows, curtain walls and doors The LEED Rating System LEED credits that can be earned with Thermal Control

63 Credit Information Your certificate of completion will be available at the CertainTeed Academy of Continuing Education continuinged.certainteed.com You will receive an with a link to access your certificate If applicable, update your profile with your AIA number for reporting. Reporting is uploaded to AIA once a week. Thank you for your attendance!

64 Thank You for Your Participation Any Questions?

65 Professional Educational Series BSP716 USGBC# Commercial Building Science - Thermal Control in Building Envelopes