What is below grade?
Below grade in real estate is a term that describes a space that is below ground level – usually referred to as a basement. In building analysis terms, it describes conditions where the envelope is in direct contact with the ground. These below-grade conditions typically have lower temperatures and higher moisture percentages than the above-grade environment which in turn can influence your building's energy consumption and expenditure loads. This article will describe how to model, export, and attribute properties to below-grade spaces for cove.tool.
How to deal with below grade floors when exporting to cove.tool?
This depends on whether the below-grade space is or is not a conditioned space:
1) If the below grade space is not conditioned
The below-grade geometry should not be exported to cove.tool. Examples include unconditioned basements, unconditioned parking structures, or low expenditure mechanical rooms.
2) If below grade space is conditioned and has the same mechanical strategies (engineering inputs) as the above-ground floors:
The geometry area values must be added on the baseline page' Below Grade Inputs as explained here and shown below. Examples include partially below-grade spaces that have the same envelope and HVAC strategies as the rest of the building.
3) If the below-grade floor(s) is [are] conditioned with different engineering inputs:
Mixed-use building type approach must be followed. Here is a tutorial to do the same.
The geometry can be exported from a 3D modeling software or using the manual mode. Following are the conditions for each export type:
// Above-grade (Manual Mode) + Below-grade (Manual mode) - Only energy
analysis page can be accessed.
// Above-grade (3D Mode) + Below-grade (Manual mode) - Only energy analysis
page can be accessed.
// Above-grade (3D Mode) + Below-grade (3D mode) - Both 3D and energy
analysis page can be accessed, however 3D analysis might not be completely
accurate. See FAQs section for more details.
If it's a parking area, a custom template must be created using the steps in the article - Parking Structures.
How to avoid overlap between the above and below grade geometry in mixed use projects?
It should be kept in mind that cove.tool can currently define geometry below-grade for 3D analysis only through the Revit plugin v2.4.0 and be positioned accordingly. However, when below-grade geometry is exported through other plugins, it will be referenced from 0 level.
Thus, when exporting geometry from other plugins either the below grade geometry can be brought in using the manual mode to avoid overlap. Or the above-grade geometry should be positioned with reference to the below grade geometry. This can be done by providing an additional 1sqft element floor at the lowest floor (of the below-grade geometry) when exporting the above-grade geometry.
How should I model partially below-grade walls?
If your below grade wall geometry is partially above ground you would split the portion of the wall that is above grade and export it through the cove.tool exterior wall view.
If the below-grade geometry is placed above the ground in cove.tool, how to create accurate 3D analysis conditions when exporting both above and below grade geometry in 3D mode?
You can create simple block like obstructions around the below grade geometry and bring them in the shading layer.
Should I create separate projects for both above and below grade geometry?
You can create separate projects if you are looking for completely accurate 3D analysis results.