“The Wood Products Council” is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) earned on completion of this program will be reported to AIA/CES for AIA members. Certificates of Completion for both AIA members and non-AIA members are available upon request. Copyright Materials
This program is registered with AIA/CES for continuing professional
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© The Wood Products Council 2012

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Radiant Barrier Sheathing Radiant Barrier Sheathing

LP Building Products 414 Union Street, Suite 2000 Nashville, TN 37219 Tony Pugel, Ph.D www. LPcorp.com Course Number: LPTS01 Senior Process Technologist Learning Units: 1.00 LP Building Products

LP Building Products is a Registered Provider with The American Institute of Architects Continuing Education Systems. Credit earned on Nashville TN completion of this program will be reported to CES Records for AIA members. Certificates of Completion for non-AIA members are available upon request. (615)598-3074

This program is registered with AIA/CES for continuing professional registration. 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 or construction or any method or manner of handling, using, [email protected] distributing or dealing in any material or product. Questions related to specific materials, methods and services should be directed to the program instructor.

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.

Slide 3 of 35 Learning Objectives – Radiant Barrier Sheathing
Outline • Introduction At the end of this program, participants will: • Heat transfer
• Radiant heat transfer 1. Understand forms of heat transfer • Radiant heat transfer in roofs and attics 2. Understand how radiant barriers affect heat transfer through roof systems • Radiant barrier types 3. Understand the benefits of a radiant barrier • Radiant Barrier Sheathing sheathing in both a heating and cooling • Other considerations environment • Case Studies 4. Understand radiant barrier sheathing applications • Building Codes and Energy Programs and their function, as well as key installation • Selection and Installation of Radiant Barrier Sheathing methods • Summary • References

Introduction Outline

• 1860 – French scientist Peclet investigated the • Introduction insulating effect of metals in reducing radiant • Heat transfer heat transfer • Radiant heat transfer
Visual reflectance or color are not the determining factors • Radiant heat transfer in roofs and attics • Radiant barrier types • 1925 – First patents on reflective surfaces for • Radiant Barrier Sheathing building insulation
Radiant barrier and reflective insulation • Other considerations introduced for commercialization • Case Studies • Building Codes and Energy Programs • 1960s – NASA developed thin, metalized films for Apollo space program • Selection and Installation of Radiant Barrier Sheathing
Radiant barrier inducted into the Space • Summary Technology Hall of Fame • References

Heat Transfer Roof/Attic Examples of Heat Transfer • Conduction – Heat transfer between adjacent solids, liquids, or gases due to • Radiation temperature differences  The roofing materials are radiantly heated from the sun

• Convection • Conduction – the transfer of heat from one place  The roofing materials conduct to another by the movement of heat from the exterior to the fluids interior surfaces • Convection • Radiation  The interior surface heats the attic – The transfer of heat through air causing hot air to rise and electromagnetic waves traveling exhaust through ridge or gable through a vacuums or an air space vents

Slide 9 of 35 Slide 10 of 35

Outline Important Concepts of Radiant Heat Transfer • Introduction • Heat transfer • Radiant heat transfer • Radiant heat transfer in roofs and attics Solar Radiation • Radiant barrier types • Radiant Barrier Sheathing • Other considerations • Case Studies Reflectivity • Building Codes and Energy Programs • Selection and Installation of Radiant Barrier Sheathing

• Summary Emissivity + Reflectivity = 1 Emissivity • References

Slide 12 of 35 Radiant Barrier Properties Radiant Heat Gain

• Radiant barriers are • In summer, heat absorbed defined to have an by roof components is emissivity of 0.1 or transferred by infrared less radiation to the attic floor

• To work effectively, • Studies show an average low emissivity of 93% of solar radiated surfaces must face heat enters a building an air space through the attic

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Outline Radiant Heat Gain in the Attic

• Introduction • Attic heat gain is primarily governed by solar radiation in • Heat transfer summer, and more by conduction/convection from the • Radiant heat transfer living space in winter. • Radiant heat transfer in roofs and attics • Radiant barrier types • Airflow does not move radiant energy, so increasing ventilation rate will not replace the efficiency gained by • Radiant Barrier Sheathing use of a radiant barrier. • Other considerations – Ventilation is still important for conduction and convection heat • Case Studies transfer in the attic/roof. • Building Codes and Energy Programs • Selection and Installation of Radiant Barrier Sheathing • Summary • References

Slide 16 of 35 Summer Radiant Heat Gain Residential Energy Usage (EIA 2013 est.)

• Summer roof sheathing temperatures can reach 160°F with attic Other, 15.5% Furnace/Boiler, 2.1%

temperatures exceeding Computers, 2.1% 120°F TV, 4.8% Dishwasher, 1.5% Heating/Cooling, 38.5% • Radiant barrier roof Washer, 0.5% Lighting, 8% sheathing blocks up to 97% of the radiant heat from being transmitted Freezer, 1.2% into the attic Dryer, 3.3% Water Heating, Cooking, 2.8% 14.1% Refrigeration, 5.6%

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How radiant barrier sheathing reduces energy costs Outline • Introduction Apply Radiant Cooling Scenario • Heat transfer Barrier • Radiant heat transfer

• Radiant barrier reduces heat movement from the roofing • Radiant heat transfer in roofs and attics 1 material to the attic space • Radiant barrier types • Radiant Barrier Sheathing • The attic space air temperature is reduced and heat • Other considerations 2 radiated from the roof to attic floor is reduced • Case Studies • Heat transfer from the attic floor to the living space is • Building Codes and Energy Programs reduced 3 • Ducting and air handling equipment in the attic are cooler • Selection and Installation of Radiant Barrier Sheathing • Summary Reduced energy costs • References

Roof Sheathing Radiant Barrier Types R R a a Radiant Barrier f f foil/film may be Installations t t e e placed in a of Radiant 1. Foil, bubble insulation, or t r number of Attic Space locations in the Barrier Types metalized films usually made J J O O attic I Insulation I S S in Attics with aluminum t t Living Space 2. Radiant barrier sheathing - Radiant Barrier Sheathing Radiant Barrier R R structural sheathing (OSB or a a Sheathing is f f placed with the plywood) with foil overlay t t e e foil facing the r r attic space Attic Space 3. Interior radiation control

coatings – “ radiation barrier Roof Sheathing R R Interior Radiation paint” a a Control Coatings f f t t are sprayed onto e e the underside of r r the roof sheathing Attic Space

Horizontal and Rafter Mounted Radiant Barriers Outline • Introduction • If interior attic gable walls are covered with the radiant barrier, roof-deck and rafter-mounted radiant barriers • Heat transfer provide equivalent ceiling heat gain reductions to • Radiant heat transfer horizontal installations • Radiant heat transfer in roofs and attics • Radiant barrier types • Horizontal application of a radiant barrieron the attic • Radiant Barrier Sheathing floor is more likely to accumulate dust which increases the emissivity of the surface • Other considerations • Case Studies • The main feature of the rafter mounted radiant barrier • Building Codes and Energy Programs is the reduction of radiant heat flow into the attic space • Selection and Installation of Radiant Barrier Sheathing – Especially important for air conditioning and ductwork • Summary • References

Radiant Barrier Sheathing Outline • Introduction • Heat transfer • Radiant heat transfer • Radiant heat transfer in roofs and attics • Radiant barrier types • Radiant Barrier Sheathing • Other considerations OSB Sheathing Standard OSB roof sheathing (PS-2 Exposure 1) • Case Studies • Building Codes and Energy Programs Maintains bond of foil to OSB during Adhesive the lifetime of the sheathing • Selection and Installation of Radiant Barrier Sheathing Aluminum Foil ~0.0025” thickness foil with • Summary adhesive and kraft paper backing • References

Radiant Barriers and Shingles Other Considerations with Radiant Barrier Sheathing

• Concern that heat would melt or degrade composite • Cell Phone Reception shingles – As with other metal building components, an already weak cell phone signal may be influenced by the presence of radiant barriers in attics and walls • Studies have demonstrated that hot summer day peak – Cell phone reception issues should be addressed through the shingle temperatures with a radiant barrier were only service provider 2-5° F higher. • Moisture condensation on foil surface – Normal daily cycle of cooling and heating is not typically a • Most roofing manufacturers do not limit applications with problem radiant barrier sheathing. You should check with your – Air and moisture movement from the living space to the attic roofing material manufacturer about your specific space may result in condensation application.

Outline Energy Savings • Introduction • Heat transfer • With R-19 insulation in the attic floor, radiant barriers • Radiant heat transfer can reduce summer heat gain by 16-42% • Radiant heat transfer in roofs and attics • Radiant barrier types • The installation of a radiant barrier resulted in peak energy use reduction three times greater than if attic • Radiant Barrier Sheathing insulation was increased • Other considerations • Case Studies • The value proposition for radiant barrier sheathing is • Building Codes and Energy Programs that it is an economical alternative to increased mass • Selection and Installation of Radiant Barrier Sheathing insulation because it addresses the predominant source • Summary (radiation) of heat in attics • References

Energy Savings Lawrence-Berkeley Air Conditioning Attic Duct Study

Energy Savings are dependent upon: • Compared attic and ceiling temperatures, duct temperatures and flows, and A/C electricity consumption before and after installing a radiant • Climate barrier on the roof sheathing • Roof slope • New unoccupied home in Austin, Texas • Ventilation rate • Location of the air conditioning and heating equipment and ductwork The Home • R-38 ceiling insulation 2 • Orientation of the home • Living Area: 1520 ft • R-6 duct insulation • Insulation levels • Slab on Grade with flat ceilings • Both air handler/duct system • Roof pitch: 6 in 12 • Window area and efficiency, number of occupants, etc. located in the attic • Brown composite asphalt shingles • Air infiltration measured

Air Conditioner Attic Duct Study Huntingdon Engineering and Environmental, Inc - • A/C energy consumption was 16% less Centex Homes Study – Houston • 80% of decrease due to reduced radiant heat gain by attic duct system • The study: – 20 to 30 temperature measurements were made in 7 similar matched pairs of houses in the Houston area – one house in each pair had radiant barrier roof sheathing and other house had traditional sheathing

• Radiant barrier homes had: – reduced attic surface temperature in the range of 17° to 29.9°F – ambient attic air temperature reductions were on the order of 12°F to 21°F – A/C coil temperature reductions in the range of 22°F to 27°F.

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Kenetech Resource Recovery, Inc – Austin, Texas LP Building Products Roaring River Energy Usage Study The study: • Evaluated the annual energy use/cost for a home • In 1999-2000 two unoccupied identical homes were monitored. • Savings provided payback for cost of product in about 2

years and an estimated 40+% rate of ROI • Radiant barrier roof sheathing versus conventional roof sheathing • Savings due to a significant reduction in heat transfer through the ductwork • R-30 blown in fiberglass insulation above the ceiling; R-11 insulation in the walls; R-22 insulation below the floors

• Heated and cooled via identical electric heat pumps with all ductwork located in the crawl space and the air handler located within the conditioned space

• Monitored for electric energy consumption temperatures and monitored at various locations within the homes, the attic spaces and the outdoor temperature

LP Building Products Roaring River Energy Usage Study Florida Solar Energy Center (FSEC) Studies • 14% summer monthly energy savings with radiant barrier sheathing FSEC has published several reports on radiant barrier • 4% winter monthly energy savings with radiant barrier sheathing technology, including the effects of:

• Ceiling insulation level,

• horizontal versus roof/rafter installation

• dust accumulation

• surface degradation

 
 





























































































Florida Solar Energy Center Study Results Building Codes and Design

• All other things being equal, the percentage reduction in • Most insulating materials are evaluated individually using a ceiling heat transfer for attic radiant barrier systems as conductive heating procedure compared to standard attics should remain constant – Uses hot air or a hot surface to generate heat flow through a regardless of ceiling insulation level. material

• Radiant barrier sheathing cannot be evaluated using this • Heat gain of the attic is reduced at the plane of the roof test method mounted radiant barrier, which is always above the insulation, so the net heat flow is reduced before it passes through the insulation. • Because radiant barriers require an air space they must be evaluated as an assembly – Aluminum is the only material exempted by FTC requirements on insulation when used for radiant barrier

Outline Building Codes and Design • Introduction • Some jurisdictions prescribe or allow the use of radiant • Heat transfer barriers in roofs to meet insulation specifications – Austin, Texas and other municipalities • Radiant heat transfer – California (2013) • Radiant heat transfer in roofs and attics – Florida (2010) • Radiant barrier types – Honolulu • Radiant Barrier Sheathing • Design using overall assembly R-value • Other considerations – Includes air spaces with reflective materials – Use energy rating programs: see resources such as RESNET® • Case Studies approved software • Building Codes and Energy Programs • Consult with radiant barrier sheathing manufacturer, • Selection and Installation of Radiant Barrier Sheathing consulting engineer, local code authorities, etc. to • Summary understand requirements • References

Radiant barriers are included in DOE Energy Star Program Oak Ridge National Laboratory Energy Savings Calculator

• Oak Ridge National Laboratories offers a simple energy savings calculator on their website (Radiant Barrier Fact Sheet)
Based on modeling program – AtticSim and EnergyPlus

• Calculator only for attic applications in the cooling season

Radiant Barrier Calculator

1a. Select Climate Zone

or

Outline • Introduction Radiant Barrier Calculator • Heat transfer • Radiant heat transfer • Radiant heat transfer in roofs and attics • Radiant barrier types • Radiant Barrier Sheathing • Other considerations • Case Studies • Building Codes and Energy Programs • Selection and Installation of Radiant Barrier Sheathing • Summary • References

Selecting a Radiant Barrier Sheathing Installation of Roof Radiant Barrier Sheathing

• Attic sheathing installation • Most OSB sheathing manufacturers – Protect from moisture prior to make radiant barrier sheathing and during installation. Keep panels the foil side clean.

• Wood structural panels may absorb – Place panels with foil side facing moisture during construction down (toward attic space) on • Perforations prevent the aluminum rafters, trusses, and gable attic walls overlay from acting as vapor barrier – OSB surface still placed up for • Proper perforations reduce trapped safety moisture in the OSB substrate and – Radiant barrier sheathing has reduce re-drying time same nailing patterns as conventional sheathing

Radiant Barrier Sheathing Installation Radiant Barrier Sheathing Installation • Radiant barrier should be placed face down, toward the interior of the attic • In a vaulted ceiling configuration, a 3/4" air space between the aluminum layer and another surface is required

Roofing Material Radiant Barrier Sheathing foil facing down Insulation ¾” minimum air gap

Gable End Installation Installation of Wall Radiant Barrier Sheathing

• Foil surface should face out, toward the exterior of the home • Radiant barrier sheathing panels used on the gable ends of an • Use furring strips to create ¾” attic are installed in the same separation between the foil and the manner siding

• In hot climate zones, you may use – Aluminum face toward the attic only on south and west walls space

• Protect radiant barrier sheathing panels from moisture and rain before and during construction –see installation directions

Outline Summary • Ceiling heat flow reductions due to radiant • Introduction barrier sheathing may: • Heat transfer – Reduce attic temperature by up to 30°F in summer • Radiant heat transfer – Produce summer cooling energy savings of up to 17% per month • Radiant heat transfer in roofs and attics – Reduce monthly winter heating cost by up to • Radiant barrier types 5%

• Radiant Barrier Sheathing • Savings are dependent upon: • Other considerations – Building design – Climate • Case Studies – Location and insulation of ducts – Localized conditions • Building Codes and Energy Programs • Selection and Installation of Radiant Barrier Sheathing • Radiant barrier sheathing is a cost-efficient • Summary and References and installation-friendly product for achieving energy savings

General References • A Summary of Fifty Years of Radiant Barrier Research (RIMA-I Questions? website, 2012) • A Comprehensive Review of Radiant Barrier Research Including Laboratory and Field Experiments ( ASHRAE Transactions, 2012) • Radiant Barrier Fact Sheet (Oak Ridge National Laboratory, 2010) This concludes • RIMA-I Handbook: Reflective Insulation, Radiant Barriers, and The American Institute of Architects Radiation Control Coatings (RIMA-I Website, 2002) Continuing Education Systems Course • Radiant Barriers (DOE, 2012) • Analysis in Support of the Radiant Barrier Fact Sheet 2010 Update (ASHRAE, 2010) • ASTM Standard C1743: Standard Practice for Installation and Use of Tony Pugel Radiant Barrier Systems in Residential Building Construction (ASTM LP Building Products 2012) [email protected] m