Useful Definitions for Understanding Radiant Barrier and Reflective Foil
ASTM: ASTM International, originally known as the American Society for
Testing and Materials, is an international standards organization that develops
and publishes voluntary consensus technical standards for a wide range of
materials, products, systems, and services.
Emissivity: The ratio of the radiant heat emitted by a surface.
ALL materials have emissivity's ranging from 0% to 100%. The lower the
emittance percentage of a material, the lower the amount of radiant heat
radiated from its surface. The naturally low emissivity property of aluminum
facing an air space results in very low emittance of heat from itself; it
does not radiate much of its own heat from itself. This naturally low
emissivity property makes aluminum ideal for use in radiant barriers.
Fire Rating: There are two organizations that define fire ratings for
building materials; The National Fire Protection Association (NFPA) and
The Uniform Building Code (UBC). NFPA's highest fire-resistance rating provided
is "Class A." UBC's highest fire-resistance rating provided is "Class 1."
Fire ratings of radiant barriers are determined by ASTM fire test E84 with a
required mounting method E2599. Our RadiantGUARD® Xtreme radiant barrier
has passed the required ASTM fire test and achieved both Class A and Class 1
Flame Spread: Indicates the relative rate at which
flame will spread over the surface of a material, as compared with flame spread
on asbestos-cement board (rated 0) and on red oak (rated 100).
Knee Wall: Typically a short wall, usually under three feet in height.
The term is derived from the association with the vertical location of the human
knee. Also commonly known as a half-wall, or partial-wall and commonly
found in attics where vaulted ceilings reach up into the attic space higher than
Mullen Burst Strength: Measurement of the amount of pressure required
to puncture a sheet of material and is expressed commonly in pounds per square
Radiant Barrier: Per the Department of Energy (DOE), a product
classified as a "radiant barrier" must have a high reflectance of 90% or more
and a low emittance of 10% or less. If it doesn't reflect at least 90% of the
radiant heat, it cannot be called a "radiant barrier."
Reflectivity: The reflectivity property of reflective
surface facing a
heat source across an air space allowing the aluminum to REFLECT
radiant heat back to the direction from which it came. Represented as a
Smoke Development: A measurement of the obscuration of
light by the combustion product stream.
Tensile Strength: The stress at which a material breaks or permanently
Wall Plate: Sometimes known as the top plate or ceiling plate, the
wall plate is typically a 2 X 4 that is nailed along the top of the wall studs
forming a wall.