Non-Residential Floor Area Allocation
The Non-Residential section of the Floor Area Allocation panel is used to describe how non-residential building area is distributed among employment uses. Employment is represented by six top-level sectors and a number of sub-sectors that nest into them. Employment density is determined by the floor area allocations, along with assumptions for the distribution of employment by subsector, floor area per employee, and non-residential building occupancy. These assumptions are determined according to project-level employment variables and defaults; see Using Library Settings for details.
Non-Residential section of the Floor Area Allocation panel
Gross floor area. The amount of gross floor area dedicated to non-residential uses. The value is set in the Building Characteristics panel and displayed here for reference.
Net floor area. Includes two values: a net floor area percentage and the resulting total net non-residential floor area in the building. Net, or leasable, floor area is calculated as the product of the net floor area percentage (also known as a net-to-gross ratio) and gross floor area.
Distribution by employment sector. UrbanFootprint quantifies the number of jobs accommodated by buildings according to specifications for how non-residential floor area is distributed, and variable assumptions for floor area per employee that are linked to the building density category specified in the Component Information panel. These specifications are required to support robust planning and analysis that account for employment by type, and the impacts of different uses on building energy use, water use, carbon emissions, and more.
Employment and associated building area are represented by six top-level sectors: Retail, Office, Public, Industrial, Agriculture, and Military. Inputs for each employment sector include gross floor area and the percentage of total gross floor area that it constitutes. For example, a building with ground-floor retail and four floors of office space above might be represented by a distribution of 20% Retail and 80% Office.
Each sector row contains a value for gross floor area and the percentage of floor area allocated to the sector. The area and percentage are tethered such that editing one automatically updates the other. The Edit button
to the right of the percentage brings up a window to allow you to set the distribution of employment by subsector, which determines the number of employees accommodated by the specified floor area. The employment sectors and subsectors are listed below.
- Retail. Includes Retail Services, Restaurant, Arts & Entertainment, Accommodation, and Other Services.
- Office. Includes Office Services and Medical Services.
- Public. Includes Public Administration and Education Services.
- Industrial. Includes Manufacturing, Wholesale, Transportation & Warehousing, Construction, and Utilities.
- Agriculture. Includes Agriculture and Extraction.
- Military. Includes Military only.
Overallocated / Unallocated. A value that appears if the sum total of floor area by sector does not equal the total non-residential gross floor area, and the percentages do not add up to 100%. Use this value to correct the floor area allocations. The Component will not be valid for use if there is any overallocated or underallocated area.
Employment by Subsector
The subsector distributions are accessed via the Edit button
located to the right of the employment sector floor area percentage. Clicking the button opens the Employment by Subsector window for the selected sector. The window for the Retail sector is shown below.
Retail Sector Employment Distribution window
Subsector employment percentage. The percentage of jobs in each subsector is an input. The floor area by subsector is calculated based on the inputs and shown in the Area column at left. The assumed floor area per employee by subsector is shown in the column at right.
Upon Component creation, the model is seeded with a default distribution of employment by subsector as specified in Library Settings. The variable assumptions for floor area per employee by subsector are also specified there. The Employment Variables and Defaults section of the Library Settings screen is shown below.
Library Settings for floor area per employee variables and employment distribution by subsector defaults
Considerations for Meeting Employment Densities
The method of deriving employment from floor area allocations ensures that employment densities are systematically related to physical building area. Densities cannot be asserted in a top-down manner without losing connections to empirical building data, or a distribution of employment by sector—both of which are fundamental to comprehensive impact analysis.
Developing a Component to meet a specific employment density may require an iterative process of adjusting building area allocations, employment distributions, floor area per employee variables, and non-residential building occupancy.
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