2008 Copyright – Reflective Insulation Manufacturers Association International

The

Reflective Insulation Manufacturers Association International

Benefits of Reflective Insulation, Radiant Barriers and IRCCs

Presented on Behalf of RIMA International

Learning Objectives• Identify what reflective products are

available, how they work and are installed

• Review thermal performance in a building envelope

• Discuss Energy Code compliance, Energy Star compliance and Federal Energy Tax credits as they apply to reflective products

• Understand how radiant barriers affect the HERS index

• Examine green building attributes (LEED and NAHB Model Green Guidelines)

About RIMA-IThe Reflective Insulation Manufacturers Association International represents manufacturers and distributors of reflective insulation, radiant barriers and interior radiation control coating materials.

RIMA International’s activities are guided by an active board of industry members who participate on national and local levels of building code organizations and governmental agencies.

Visit us at www.rimainternationa.org

RIMA-I MembersPlatinum

Members• Astro-Foil/

Innovative Energy

• Covertech• KdB Isolation

SA• RoyOMartin• Reflectix Inc• TVM Building

Products

Advanced TechnologyAir-Cell Innovations Pty LtdAstro Reflective Insulation

ASCelplast Metallized

ProductsCleveland Laminating

CorpCompac CorporationDunmore CorporationDuPont TyvekESP/Low-EFi-Foil Company Foil Barrier InsulationHeartland Insulation

SupplyIdeal Tape Company IncInnovative Energy,

CaliforniaInnovative Insulation Inc.Insulation Solutions, Inc.Isolant S.A.LIT Works Co.

Louisiana Pacific Midwest Low-E MWI ComponentsPolyair Polyon Barkai Ind.ProdexPT Insfoil PradanasaktiRadiant Barrier

SpecialistsRadiant GuardResisto, a Div. of

SopremaSTS CoatingsSan Miguel Woven

ProductSigma Technologies Int’lSolecValeron Strength FilmsVenture Tape Corp

Overview Definitions & Standards

Types and Applications

Insulation & Building Science

Codes, National Accrediation, GreenQ&A

Types of Products Reflective Insulation

Radiant Barriers

Low-e Spray Coatings

Definitions• Reflective Insulation: one or more low

emittance materials (0.10 or less) installed adjacent to air spaces in an enclosed air space. The low emittance surfaces reduce radiation across the air space. The layer(s) reduces radiant heat and convective heat transfer

• Reference Documents for Reflective Insulation: ASTM C1224 - Standard Specification

ASTM C727 - Installation

Examples of Reflective Insulation Applications

R-Values apply

Floor or Crawl Space

Enclosed Cavity

Commercial Ceiling –Metal Furring & Drywall

(not pictured) Creates Enclosed Cavity

Masonry Walls

Metal Buildings

Definitions• Radiant Barriers: one or more low

emittance materials (0.10 or less) installed adjacent to large open air spaces. The primary function of the low emittance surface(s) is to reduce radiation across the air space.

• Reference Documents for Reflective Insulation: ASTM C1313 - Standard Specification

ASTM C1158 - Installation

Examples of Radiant Barrier Applications

Draped Method

Bottom of Roof Rafter - Method

Deck Applied Method

Low-Emittance Products

Definition of an IRCCAn Interior Radiation Control Coating is a non-thickness dependent, low emittance coating. When applied to non-porous building materials such as plywood, OSB, metal sidingor plasterboard, according to the manufacturer’s Installation instruction, it lowers the normal surface emittance of these materials to 0.24 or lower.

Physics of an IRCCAn IRCC works by changingthe emittance of the surface where it is applied. Building products, such as wood, brick, painted surfaces and plasterboard exhibit high emissivities (0.7 - 0.95). When heated above the temperature of adjacent surfaces, they radiate most of their heat energy to cooler surfaces. An IRCC works by lowering their surface emittance to 0.24 or lower, lessening their ability to radiate heat.

IRCCS spray-applied to steel sidewalls of large construction storage warehouse.

An IRCC System A building constructionconsisting of a low- emittance surface bounded by an open air space. An IRCC is used for the sole purpose of limiting heat transfer by radiation and is not specifically intended toreduce heat transfer by convection or conduction. (ASTM C 1321, section 3.2.3) Thus, an IRCCS is similar to a Radiant Barrier System (RBS) but is somewhat less efficient due to its higher emissivity and is comprised of a coating on a building surface, not a foil or film product.

IRCCS Spray-applied to underside of steel roof decking and trusses in an ice hockey arena.

Advantages of an IRCCAn IRCC is normally applied using airless spray equipment, resulting in very low labor costs and greatly reduced installation times. Also, a water based IRCC can be safely installed in existing structures where the costs of installing foil or film products may be prohibitive or impractical. An IRCC may also be used in many manufactured products (such as infrared heat reflectors of automotive parts) where it is impractical to adhere foil or film radiant barriers.

Building Science

Reflective Insulation

RI: An enclosed air space with a low- emittance surface. ●●●Radiation is suppressed

MI: An enclosed air space filled with solid fibers. ●●●Convection is suppressed

Radiation is Suppressed by a Low-emittance SurfaceKey Words: emittance, reflectanceOpaque materials – zero transmission

Reflectance: fraction n incident radiation that

is not absorbed.

Emittance: (actual rad.)/(blackbody rad.)

A blackbody absorbs all incident radiation. approximated by carbon black

Emissive Power (Radiation)

All surfaces above absolute temperature give off radiation.

Expressions for Heat Flux

(Btu/ft2∙hr)

0.1713x10-8∙( T + 460 )4 for blackbody

E∙( 0.1713x10-8∙( T + 460 )4 ) for real surface

F12∙E∙( 0.1713x10-8∙(( T1 + 460 )4- (( T2 + 460 )4

for net exchange

Radiation from a Surface Increases as the Temperature of the Surfaces Increases

Total Emissive Power of a Blackbody Surface

25

75

125

175

225

275

0 25 50 75 100 125 150 175

Temperature (F)

Em

issiv

e P

ow

er

(Btu

/ft^

2.h

)

The Reduction in Emission due to Lowering the Emittance is Dramatic

Emissive Power

0.0

50.0

100.0

150.0

200.0

250.0

0 40 80 120 160

Temperature (F)

Po

we

r (B

tu/f

t^2

.h)

Black Body

Wood Sheathing

IRCC E = 0.22

Foil E = 0.03

Net Exchange Between Large Parallel Surfaces

Net Exchange between Large Parallel Surfaces

The Net Exchange for this arrangement

of surfaces is given by:

F12 = 1/( 1/e1 + 1/e2 – 1)

e1 e2 F12

1.00 1.00 1.00

0.87 0.87 0.77 0.87 0.22 0.21 ↓

73% 0.87 0.03 0.03 ↓ 96%

Diagram from ASTM C 1340 – Attic Radiation Terms Radiant Barrier Theory

Results in the AtticAttic Radiant Barrier

Summer

1. Reduces radiation heat transfer from the roof deck to the floor of the attic.

2. Reduces the surface temperature of the attic floor or the insulation on the attic floor.

3. Reduces the temperature difference from top of insulation to bottom of insulation.

4. Reduces the heat flow into the conditioned space.

Results in the AtticAttic Radiant Barrier

Winter

1. Reduces radiation heat transfer from the surface of the attic floor insulation to the roof deck.

2. Increases the surface temperature of the attic floor insulation.

3. Reduces the temperature difference from bottom of the insulation to top of the insulation.

4. Reduces the heat flow out of the conditioned space.

5. Solar gain will be reduced.

Attic with RB is Cooler than Attic no RB Houston – Summer 2007

Temp Diff

-10

0

10

20

30

40

0 12 24 36 48 60 72 84 96

Time (hrs)

Def

rees

F

Side View of WallExterior l → l Interior Enclosed Air

Space

100 F l → l 70 F Large Parallel Surfaces

l → l 3.5 Inches Across

l → l Heat Flux

TotalCond Conv Rad E warm E cold 35.84 1.54 8.66 25.640.87 0.87

11.17 1.54 8.63 1.00 0.87 0.03 10.68 1.54 8.63 0.54 0.03 0.03

Reduce Convection by Changing Gap SizeWall Cavity as BeforeDescription R (1-D) Conventional

Unitswood-wood 0.84wood-foil 2.69foil-foil 2.81wood-foil-wood6.73Wood-foil-foil-wood 12.41

Reflectives Can Be Combined with other Insulation Types to form Hybrid Systems

RIS + Mineral FiberWood Frame Cavity [wall, floor, or

ceiling](Nominal 2x6)

Mineral Wool Batt + RISCathedral Ceiling: R 13 @ 3.5 + R 5 to10. (Heat flow down at 45)

Cellular Plastic + RISWall: 6*T + RIS

Hybrid System Consisting of Polyurethane and a Reflective System in the Enclosed Air SpaceNominal 2x6 Frame Wall

Wall Cavity R vs. R* of Foam(Reflective Insulation System)

57.510

12.515

17.520

3 4 5 6 7

R-per-inch of Foam

Wal

l Cav

ity R

0.5 in.

1.0 in.

1.5 in.

2.0 in.

Summary Statements

RIS, RB, and IRCC utilize surfaces with low emittance and high reflectance to reduce heat flow.

Reflective air spaces are well understood with R-values that can be measured and calculated.

RB have demonstrated savings that result from reduced radiation transport and cooler attic air spaces.

Hybrid systems can be tailored to provide excellent systems with demonstrated thermal characteristic.

Green

LEED or NAHB Guidelines

• Reduce Energy Use – Primary Benefit

• Materials and Resources

• Regional Materials

Green Building; is the practice of increasing the efficiency with which buildings use resources – energy, water and materials – while reducing building impacts on human health and the environment, through better siting, design, construction, operation, maintenance, and removal – the complete building cycle.

Wikipedia

The greatest benefits of radiant barriers and reflective insulation used in Green Building are energy efficiency and comfort for a calculable return on investment through Energy Efficient Design and energy modeling.

Green Building

Green Building Project Certification

US Green Building Council’s (USGBC) LEED/Leadership in Energy and Environmental

Design, includes LEED for New Construction, LEED for Core and Shell, LEED for Schools, etc.

ENERGY STAR Qualified Homes and Designed to Earn the ENERGY STAR for Commercial Buildings

NAHB Model Green Home Guidelines------------------------------------------------------------------------------------------Radiant barriers and reflective insulation not only help projects

qualifyfor Certification, but they also help reduce operating costs

through…1) Energy savings2) Material and resource usage3) Increased productivity

Qualifying for LEED Certification

Energy and Atmosphere;Optimize Energy Performance…Reflective Insulation can be used as an option to (or) in conjunction with other

Insulationto add R-Value.

Radiant Barriers help reduce radiant heat transfer and improve the performance of roof

and ceiling insulation.

Materials and Resources;Building Reuse, Maintain 50% of Interior non-structural elements…Reflective Insulation and Radiant Barriers could be left in place as part of the

existingwall, roof, floor or ceiling system.

Materials Reuse…Reflective Insulation and Radiant Barriers could be removed during demolition andreused in new construction.

Indoor Environmental Quality;Thermal Comfort: Design…Reflective Insulation and Radiant Barriers can be used to improve building

envelope’sperformance and increase thermal comfort since they reduce radiant heat transfer.

Qualifying for ENERGY STAR and NAHB

Reflective insulation and radiant barriers help youqualify for the HERS Index Requirements(Energy Star Qualified Homes)

Radiant barriers help you qualify for “Renewableenergy/solar heating and cooling – Using passiveCooling” (NAHB Model Green Home Building

Guidelines)

Energy Star Compliance

• R-values or• Credits in Software Programs

Impact Ceiling Heat Flow & HVAC Ducts and Systems located in unconditioned areas

2. Energy Star Compliance

In order to be considered an Energy Star Compliant Home there must be a home energy rating which involves an analysis of the home’s construction plans and onsite inspection resulting in a HERS Index score.

HERS Index of 85 in climate zones 1-5

HERS Index of 80 in climate zones 6-8Reference IECC 2006 for Climate Zones

Effect of Radiant Barrier on Code Compliance

Example

Using Energy Gauge USA Software

Understanding the HERS Rating

What is the HERS Index?The HERS Index is a scoring system established by the Residential Energy Services Network (RESNET) in which a home built to the specifications of the HERS Reference Home (based on the 2006 International Energy Conservation Code) scores a HERS Index of 100, while a net zero energy home scores a HERS Index of 0. The lower a home’s HERS Index, the more energy efficient it is in comparison to the HERS Reference Home.

Understanding the HERS Rating

A home energy rating involves an analysis of a home’s construction plans and onsite inspections. Based on the home’s plans, the Home Energy Rater uses an energy efficiency software package to perform an energy analysis of the home’s design. This analysis yields a projected, pre-construction HERS Index. Upon completion of the plan review, the rater will work with the bulder to identify the energy efficiency improvements needed to ensure the house will meet ENERGY STAR performance guidelines. The rater then conducts onsite inspection, typically including a blower door test (to test the leakiness of the house) and a duct test (to test the leakiness of the ducts).

Effect of Radiant Barrier on HERS Index Score

Radiant Barrier adds 3 HERS Points to Energy

Star Compliance

ModelAttic Floor

Walls A/C RB HERS

Charlotte R-30 R-13 Seer 14 None 85

R-30 R-13 Seer 14 Yes 82

Miami R-30 R-13 Seer 14 None 89

R-30 R-13 Seer 14 Yes 86

Las Vegas

R-30 R-13 Seer 14 None 82

R-30 R-13 Seer 14 Yes 79

Federal Tax Credits Commercial Buildings: Taxpayers can enjoy a

deduction of up to $1.80 per square foot for buildings that achieve a 50% reduction in annual energy costs related to heating, cooling, water heating and interior lighting - costs that are defined by the ASHRAE standard.

New Homes: A credit of up to $2,000 is available to home builders who build homes projected - and demonstrated - to save at least 50% of the heating and cooling energy of a comparable home that meets the standards of the 2004 International Energy Conservation Code (IECC) Supplement.

Existing Homes: Current homeowners are eligible for different tax credits based on a variety of energy-efficiency measures - such as improving insulation - with a $500 cap.

Questions?

Reflective Insulation Manufacturers Association

International (RIMA International)

800/279-4123 www.rimainternational.org