Reflective Foil and Radiant Barriers get credits in LEED™

Reflective Foil and Radiant Barriers get credits in LEED™

By Paul R Bertram, Jr. FCSI, CDT

In the past decade there has been a great deal written about sustainable
building and the need for better understanding about the science required
for a properly designed building envelope. There has also been a
movement for greater sensitivity of the environment and energy efficiency
in construction. Even with this movement, the theory of “Green” building
and “Sustainable” design has found few projects including this theory in the
stated design intent. 

As reported in The Future of Green Developments in the A/E/C Industry by
Manar Shami and Thomas R. Dunn, Green buildings have been defined as
systems that exist in harmony with the environment. Sustainability, in their
report, is defined as the relationship between the dynamic human
economic systems with the slower-changing ecological systems.

There has been much published about the benefits of increased insulation
but there must be an understanding of the dynamics of the total efficiency
of the building envelope and related systems. This holds true in concept to
the entire building project and its relationship to community and

The US Green Building Council is a nonprofit organization that is
spearheading the effort to standardize the green building industry. It
encompasses engineers, architects, specifiers, commissioning agents,
facilities managers, code officials, specialty consultants and owners. It was
founded in 1993 as a result of a lack of clear definition of “Green” building.
One of the programs developed by the USGBC is the LEED‘ RatingSystem which is gaining national and international attention as a baseline
for developing “Green”/”Sustainable” building projects. In November of
2002, the USGBC held their first annual International Green Building
Conference and Expo. Expected attendance was estimated at 1600 to
1800 but the final tally counted 4100 registered attendees. The 2003
November conference, to be held in Pittsburgh, is estimating 6,000 in
attendance. The USGBC along with organizations like the US EPA3.
(Environmental Protection Agency), US DOE4. (Department of Energy),
The Whole Building Design Institute4., and the Sustainable Buildings
Industry Council5. are helping to promote greater energy efficiency with
the goal of reducing energy loads and related environmental impacts.

Defining Reflective Insulation and Radiant Barriers

ASTM C1224 defines the standard specification and testing of reflective
insulation and ASTM C727 provides guidelines for the use and installation
of reflective insulation. Reflective insulation differs from other insulating
materials in the primary manner in which it retards heat transfer. Reflective
insulation blocks radiant heat transfer between a heat-radiating surface
and a heat-absorbing surface through the use of low emittance materials.
The thermal performance or the reduction of radiant heat transfer is
directly proportional to the surface emittance of the radiant barrier material.
Reflective insulation materials includes paper, plastic, and aluminum foil or
metalized aluminum substrates. In addition to reducing radiant heat
transfer, reflective insulation functions by reducing convective heat transfer
by trapping air or other gasses with multiple layers of these materials. This
is the same principle that is used in high performance windows (for
example a double paned low-e glazing). Types of reflective insulation
includes: expandable multi-layer with one or more aluminum layers,
aluminum faced plastic bubble, and aluminum faced flexible foam.
Products are available in solid form or perforated, which allow free
passage of moisture.

ASTM C1313 defines the standard specification and testing and ASTM
C1158 provides a guideline the use and installation of radiant barriers
function by reducing heat transfer by radiation. Typically radiant barriers
are installed in areas of the building envelope that are ventilated like attic
spaces. Testing for R-values requires trapping or containing air or gases
therefore R-values are not associated with the thermal performance of
radiant barriers. Numerous studies have documented the benefits of this
technology. State energy codes as well as thermal modeling (Eight Edition
of Manual J) recognize the benefits of radiant barriers and their impact on
building envelopes.

Defining “green” / “sustainable” building products.

“Green”, in the context of this article, refers to “Green Building” as defined
in ASTM E 2114-01 (Standard Terminology for Sustainability Relative to the
Performance of Buildings): a building that provides the specified building
performance requirements while minimizing disturbance to and improving
the functioning of local, regional and global ecosystems both during and
after its construction and specified service life.

Environmental Building News ( in their Vol.
9 No.1 January 2000 edition published an article entitled Building
Materials: What makes a product green? In the article there is a Summary
of Product Standards for GreenSpec that gives us some additional
clarification. This is a partial listing:

1. Products made from environmentally attractive materials
- Products made with post-consumer/industrial content
2. Products that are green because of what isn’t there
- Alternatives to ozone-depleting substance
3. Products that reduce environmental impacts during construction,
renovation or demolition
- Products that reduce the impact of renovation
4. Products that reduce environmental impacts of building operation
- Building components that reduce heating and cooling loads
- Products with exceptional durability or low maintenance requirements
5. Products that contribute to a safe, healthy indoor environment
- Products that don’t release significant pollutants into the buildings
ASTM E 2129 – 01 : Standard Practice for Data Collection for
Sustainability Assessment of Building Products states: 1.1 This practice
offers a set of instructions for collecting data to be used in assessing the
sustainability* of elements or products for use in both commercial and
residential buildings. Specifiers may want to include this standard in project
specifications to avoid “GreenWash” or unsubstantiated claims or
positioning about “Green” products.

Data areas reviewed include:

1. Materials
2. Manufacturing
I. Process
3. Operational Performance of Installed Product
4. Indoor Air Quality
5. Corporate Environmental Policy.

Potential LEED Credits

The LEED Rating System includes several key areas of opportunity for
Radiant Foil insulation. There are a number of LEED project Rating
Systems: New construction and major renovation LEED 2.1, Existing
Building Operations LEED-EB, Commercial LEED-CL, Core and Shell and
most recent is LEED for Retail. Additionally, there is a draft for a proposed
LEED Residential rating system.Note: Reflective insulation and radiant barriers have potential for
contributing points for LEED credits in most of these systems.

Potential Point Opportunities and Strategies for Radiant Foil

LEED 2.1 Credits

Heat Islands Effect:
Roof Intent

Reduce heat islands (thermal gradient differences between developed and
undeveloped areas) to minimize impact on microclimate and human and
wildlife habitat.


Use ENERGY STAR ® compliant (highly reflective) AND high emissivity

(emissivity of at least 0.9 when tested in accordance with ASTM 408) for a
minimum of 75% of the roof surface; …

Note: The ENERGY STAR roof program does not include insulation in
consideration of making roofs more energy efficient. RIMA, and other
insulation associations should be collectively lobbying this government
program to be included as an integral component of a roof system.

Minimum Energy Performance

Establish the minimum level of energy efficiency for the base building and


Design the building to comply with ASHRAE/IESNA Standard 90.1-1999
(without amendments) or the local energy code, whichever is more stringent.
Note: Reflective Insulation and Radiant Barriers definitely contribute to
compliance with model energy codes. It is also a very cost effective
solution for increasing insulation efficiency and reducing the energy load
on mechanical equipment.

Optimize Energy Performance

Achieve increasing levels of energy performance above the prerequisite
standard to reduce environmental impacts associated with excessive energy use.


Reduce design energy cost compared to the energy cost budget for energysystems regulated by ASHRAE/IESNA Standard 90.1-1999 (without

Note: Reduced load requirements have the potential for smaller
mechanical units and less energy demand.

Recycled Content: Use 5% post-consumer or 10% post-consumer
+ post-industrial (There is also a 50% program)
Recycled content materials shall be defined in accordance with the Federal
Trade Commission document, Guides for the Use of Environmental Marketing
Claims, 16 CFR 260.7 (e), available at

Regional Materials: 20, 50% manufactured regionally


Use a minimum of 20% of building materials and products that are
regionally within a radius of 500 miles.

Note: Beyond the obvious 500 mile radius factor for availability a case
might be lobbied that because of the lightweight foil material can be
shipped UPS, which also saves from the individual expense of a typical
building material.

Innovation in Design


To provide design teams and projects the opportunity to be awarded points
for exceptional performance above the requirements set by the LEED
Green Building Rating System and/or innovative performance in Green
Building categories not specifically addressed by the LEED Green Building
Rating System.

LEED Residential Note: This is a wild card category where innovation in
design can be submitted for unique applications. As an example one could
build a case for utilizing reflective insulating materials either exclusively or
in conjunction with other insulating materials.

LEED Residential is in DRAFT form
01.pdf )
This document has not been balloted by the US Green Building Council.

Note: Significant opportunities for reflective insulation and radiant barrier
products exist within this proposed program because of much of the
criteria are found in LEED 2.1. However, one particular strength in the
Residential LEED, is the acceptance of Energy Star energy program.

LEED to economic sense

Arthur Gensler, Jr., Chairman and Founder or Gensler Architecture,
Design and Planning Worldwide, said that opportunity in “Green” building
is for those who move rapidly. Beyond the environmental sensitivity of
Green Building there must be an economic based social and financial

Robert Hascall, Senior Associate Vice president, Facilities Management, at
Emory University discussed how Emory already has 10 LEED Certified
buildings with more scheduled. The cost issue for certification is upfront on
every project.

Concluding Observations:

One of the perceptions in the built environment is that building green costs
more than it is worth and design possibilities are restricted. The reality of
“Green” building is that many firms and owners are just now beginning to
understand the value of these design concepts. The LEED green rating
systems of the USGBC is evolving quickly to become the industry “defacto”
standard for building “Green” / “Sustainable”.

Submitted by:
Paul R. Bertram Jr., CSI, CDT, is an advisory board member of The
Construction Specifier, CSI's official publication, and a member of the
Construction Writers Association (CWA). He is also an associate
member of the American Institute of Architects (AIA), a professional
member of Southern Building Code Congress International (SBCCI),
the U.S. Green Building Council (USGBC), and the National Institute
of Building Sciences (NIBS). Mr. Bertram is president and CEO of
PRB Planning/PRB Design, a firm specializing in building business
strategies for manufacturers in the A/E/C industry, and delivers
seminars on e-business strategies. He can be reached via email at


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