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