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building-area-classification.md

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+---
+id:
+aliases: []
+title: Building Area Classification
+tags:
+  - authorship/original
+  - destiny/permanent
+  - status/draft
+  - topic/construction
+  - type/encyclopedia-entry
+---
+# Building Area Classification
+
+* G = Gross Area
+* R = Rentable Area
+* U = Usable Area
+* N = Net Area
+
+$$
+G > R > U > N
+$$
+
+## Gross Area (GSF)
+
+Gross Area is the total floor area of a building.
+
+Whether the area includes exterior wall area
+depends on the relevant standard.
+
+* International Building Code (IBC):
+    measured to the interior face of exterior walls.
+
+* Building Owners and Managers Association (BOMA):
+    total footprint, including exterior wall thickness.
+
+## Rentable Area (RSF)
+
+Rentable Area includes tenant exclusive space (usable area)
+plus a pro-rata share of common areas (load factor).
+
+$$
+\text{Rentable Area} = \text{Usable Area} \times (1 + \text{Load Factor})
+$$
+
+### Usable Area (USF)
+
+Usable Area is the tenant's exclusive space.
+the area physically occupied and controlled by a specific tenant.
+
+Usable Area includes:
+
+* Primary functional areas (offices, workstations, meeting rooms)
+* Internal circulation within the tenant's space
+* Columns, recesses, and other features within the leased boundary
+
+But excludes:
+
+* Common corridors and lobbies
+* Shared service areas
+* Major vertical penetrations (elevator shafts, stairs)
+
+### Net Area (NSF)
+
+the actual functional, programmable space.
+
+Also called Net Assignable Area.
+
+Net Area includes:
+
+* Actual functional program spaces (offices, classrooms, apartments)
+* Space planned for specific uses in a program
+
+But it excludes:
+
+* All circulation (even within tenant space)
+* All service and support spaces
+* Structural elements, wall thicknesses
+
+## Building Efficiency
+
+Building efficiency is the ratio of usable or rentable area to gross area.
+This denotes what percentage of the building is functionally usable.
+
+$$
+\text{Building Efficiency} = \frac{ \text{Net Assignable Area} }{ \text{Gross Area} }
+$$
+
+A higher percentage means less area is lost to structure,
+mechanical spaces, or circulation.
+
+* Office buildings: 75-90%
+* Residential buildings: 80%+
+* Hospitals and laboratories: 50-65%