Attic Kneewall Air Barrier Foam Plastic Not Allowed ?

The 2006 IRC (section 314) has been almost entirely re-written on foam plastic. I have been having issues where builders are not only told this is acceptable, but are recommended to do it for the 2006 Energy Code. I will not say who, but they teach lots of energy classes. In some cases this is where the builder has a 2×4 studed attic knee-wall and instead of making it a 2×6 wall he uses R13 and 2 layers of R3 Foam Plastic which bring s it to the Required R18.

The code says
R314.5.3 Attics. The thermal barrier specified in Section
314.4 is not required where attic access is required by Section
R807.1 and where the space is entered only for service
of utilities and when the foam plastic insulation is protected
 against ignition using one of the following ignition barrier
materials:
    1.)  1.5-inch-thick (38 mm) mineral fiber insulation;
    2.)  0.25-inch-thick (6.4 mm) wood structural panels;
    3.)  0.375-inch (9.5 mm) particleboard;
    4.)  0.25-inch (6.4 mm) hardboard;
    5.)  0.375-inch (9.5 mm) gypsum board; or
    6.)  Corrosion-resistant steel having a base metal thickness
of 0.016 inch (0.406 mm).
The above ignition barrier is not required where the foam
plastic insulation has been tested in accordance with Section
R314.6.

R314.6 Specific approval. Foam plastic not meeting the
requirements of Sections R314.3 through R314.5 shall be specifically
approved on the basis of one of the following
approved tests: NFPA 286 with the acceptance criteria of Section
R315.4, FM4880,UL1040 orUL1715, or fire tests related
to actual end-use configurations.
The specific approval shall be
based on the actual end use configuration and shall be performed
on the finished foam plastic assembly in the maximum
thickness intended for use. Assemblies tested shall include
seams, joints and other typical details used in the installation of
the assembly and shall be tested in the manner intended for use.

Now lets look at whats on the products. Most of the time it says on the product that it requires an igntion barrier
Note: You can click on the image to get a larger image.
The Dow Blue Board. I spoke with Dow and thermax is the only line
of foam plastic that can be used in attics.

Dow Blue Board

Dow Blue Board

More Dow Blue Board

More Dow Blue Board

 

Green Gaurd Plygood Ultra

Green Gaurd Plygood Ultra

Owens Corning Pink Board

Owens Corning Pink Board

Below is some kind of thermal board. I have not read the
ICC-ES reports on this.
Protected Foam Board

Protected Foam Board

Any comments on this would be appreaciated.

 

 

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