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Permability of building materials and good data on embodied energy

Ed Welch | Posted in GBA Pro Help on

Wondering whether any of you could turn me on to good sources (books or websites) for finding out the permeability of building materials….and also a good site that discusses the embodied energy of building materials…for instance, the embodied energy of different types of spray foam insulation, which I hear has huge embodied energy. Thanks.

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  1. Riversong | | #1

    MJ/kg BTU/lb BTU/cf per R-sf

    Cellulose - dense packed 1.8 752 2257 49

    Mineral Wool - loose fill 14.6 6277 9415 245

    Mineral Wool - batts 14.6 6277 15692 311

    Mineral Wool - drain board 14.6 6277 50216 973

    Fiberglass – batts 30.3 13027 13027 345

    Polyisocyanurate - rigid board 69.8 30009 60018 715

    Polyurethane – sprayed 74.0 31815 63630 899

    Icynene – sprayed 41.9 18000 9000 208

    XPS - rigid board 117.0 50302 90543 1509

    EPS - rigid board 117.0 50302 50302 1075

  2. Riversong | | #2

    Yup, I had a feeling the above chart would lose its formatting. If you can make sense of the data, the first number is Mj/kg, the second, BTU/lb, the third BTU/cf, and the fourth is BTU per square foot of R-1 (to compare the insulation types adjusted for R-value).

    There's tons of data on the web. Try Googling. Or if you need specific data, feel free to ask as I've got it all on my hard drive.

    Perm ratings are relatively consistent, since there are ASTM standards (ASTM E-96) for testing, but be sure you're comparing either dry-cup or wet-cup. There are actually 6 different testing methods covered under that one standard.

    But embodied energy numbers are approximations, dependent upon geographic location, industrial production method, and other variables and assumptions. Be sure you're comparing EE per unit weight or EE per unit volume or EE per R-value equivalent. And much of the data is in metric units of Mj/kg or Mj/m3.

  3. GBA Editor
    Martin Holladay | | #3

    Here's a link to a useful table from our friends at Building Science Corporation. The table includes vapor permeability data.
    "Building Materials Property Table."

  4. Riversong | | #4

    The BSC materials property table is one of the more useful available on the web, but be aware of some non-standard data that can be potentially misleading.

    For instance, while the table is labled "material properties", the perm numbers for wood and vinyl lap siding, which are in quotes, are for as-built assemblies not materials. Sources give perm values for a 3/4" wood board of anywhere from 0.3 to 4.1, while BSC offers "35 perms" for wood lap siding and "70 perms" for vinyl lap siding, when vinyl itself has a perm of 0.05/in (perhaps 0.1 for the siding material).

    The table also lists the water absorption of icynene as 0% because plastic doesn't absorb water, but tests conducted by the National Research Council of Canada, according to ASTM D2842-69 (water absorption of rigid cellular plastics) showed 34% by volume because of its open-cell structure. This is one of the examples of a non-hygroscopic material being formed into a hygroscopic matrix (like EPS).

  5. Ed Welch | | #5

    Thanks guys.....

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