FoundationWall insulation flexibility

[shorowit]

Allows:

1. Insulation on a foundation wall that doesn't start at the top of the wall.
2. Separate interior vs exterior insulation specifications.

For walls described with an insulation layer, both interior and exterior layers now must be described. For example, an uninsulated wall that used to be described as

          <FoundationWall>
            <SystemIdentifier id='FoundationWall'/>
            ...
            <DistanceToBottomOfInsulation>0</DistanceToBottomOfInsulation>
            <Insulation>
              <SystemIdentifier id='FoundationWallInsulation'/>
              <Layer>
                <InstallationType>continuous</InstallationType>
                <NominalRValue>0</NominalRValue>
              </Layer>
            </Insulation>
          </FoundationWall>

is now described as

          <FoundationWall>
            <SystemIdentifier id='FoundationWall'/>
            ...
            <Insulation>
              <SystemIdentifier id='FoundationWallInsulation'/>
              <Layer>
                <InstallationType>continuous - exterior</InstallationType>
                <NominalRValue>0</NominalRValue>
                <extension>
                  <DistanceToTopOfInsulation>0</DistanceToTopOfInsulation>
                  <DistanceToBottomOfInsulation>0</DistanceToBottomOfInsulation>
                </extension>
              </Layer>
              <Layer>
                <InstallationType>continuous - interior</InstallationType>
                <NominalRValue>0</NominalRValue>
                <extension>
                  <DistanceToTopOfInsulation>0</DistanceToTopOfInsulation>
                  <DistanceToBottomOfInsulation>0</DistanceToBottomOfInsulation>
                </extension>
              </Layer>
            </Insulation>
          </FoundationWall>

For walls described with an assembly R-value, there is no change required. A wall can continue to be described like so:

          <FoundationWall>
            <SystemIdentifier id='FoundationWall'/>
            ...
            <Insulation>
              <SystemIdentifier id='FoundationWallInsulation'/>
              <AssemblyEffectiveRValue>10.69</AssemblyEffectiveRValue>
            </Insulation>
          </FoundationWall>