DetailedConstruction element for surfaces

[shorowit]

Strawman proposal:

LayerType choices:

• exterior finish
• sheathing
• continuous insulation
• framing/cavity insulation
• structural core
• interior finish
• subfloor
• other

Example for wood stud wall:

<DetailedConstruction>
  <SystemIdentifier id='WoodStudWallConstruction'/>
  <!-- Brick siding -->
  <ConstructionLayer>
    <LayerType>exterior finish</LayerType>
    <LayerThickness>4.0</LayerThickness>
    <LayerMaterial>
      <MaterialType>brick</MaterialType>
      <RValue>0.44</RValue>
    </LayerMaterial>
  </ConstructionLayer>
  <!-- R-5 continuous insulation -->
  <ConstructionLayer>
    <LayerType>continuous insulation</LayerType>
    <LayerThickness>1.0</LayerThickness>
    <LayerMaterial>
      <MaterialType>XPS</MaterialType>
      <RValue>5.0</RValue>
    </LayerMaterial>
  </ConstructionLayer>
  <!-- 2x6, 24" oc wood framing w/ R-13 cavity insulation -->
  <ConstructionLayer>
    <LayerType>framing/cavity insulation</LayerType>
    <LayerThickness>3.5</LayerThickness>
    <LayerMaterial>
      <AreaFraction>0.8</AreaFraction>
      <MaterialType>fiberglass batt</MaterialType>
      <RValue>19.0</RValue>
    </LayerMaterial>
    <LayerMaterial>
      <AreaFraction>0.2</AreaFraction>
      <MaterialType>wood stud</MaterialType>
      <RValue>6.875</RValue>
    </LayerMaterial>
  </ConstructionLayer>
  <!-- 0.5 in drywall -->
  <ConstructionLayer>
    <LayerType>interior finish</LayerType>
    <LayerThickness>0.5</LayerThickness>
    <LayerMaterial>
      <MaterialType>gyp board</MaterialType>
      <RValue>0.45</RValue>
    </LayerMaterial>
  </ConstructionLayer>
</DetailedConstruction>

[shorowit]

• Add LayerType element with choices like "siding", "insulation", "sheathing", "interior finish", ...

[nmerket]

🎥 Discussion in HPXML Working Group Meeting 2023-02-14

[shorowit]

• Top to bottom for horizontal surfaces instead?
• What about interior partition walls/floors (e.g., floor between conditioned stories)?
• Think about expanding the LayerType choices and/or making them more specific.

[nmerket]

🎥 Discussion in HPXML Working Group Meeting 2023-03-14

[shorowit]

@GamalielL Regarding the convention of the order of construction layers, what do you think about an element to describe it? For example, there could be a ConstructionLayersOrder element with choices of "exterior to interior", "interior to exterior", "top to bottom", and "bottom to top". Is the flexibility worth the extra complexity? Or should we just force all HPXML users to do it the same way?