About Calculating Spaces Based on the BOMA Standard

BOMA is an area calculation standard used predominantly in the United States. The BOMA standard included in AutoCAD Architecture# includes the subset of BOMA rules that are described in the following sections.

In the BOMA area calculation standard, spaces are classified as follows:

Classification Space Type
Office Area Office
Store Area Store
Major Vertical Penetration (MVP) Stairs, elevator shafts, flues, pipe shafts, vertical ducts, atria, atrium spaces above the finished floor, light wells, and similar penetrations above the finished floor
Note: Not included are vertical penetrations built for the private use of a tenant occupying office area on more than one floor.
Floor Common Area (FCA) Washrooms, janitorial closets, electrical rooms, telephone rooms, mechanical rooms, elevator lobbies, and public corridors
Building Common Area (BCA) Lobbies, atrium spaces at the level of the finished floor, concierge area or security desks, conference rooms, lounges or vending areas, food service facilities, health or fitness centers, daycare facilities, locker or shower facilities, mail rooms, fire control rooms, fully enclosed courtyards outside the exterior walls, and building core and service areas such as fully enclosed mechanical or equipment rooms.
Exterior Exterior spaces
Street frontage Exterior space of store spaces at street level

Calculation Rules for AutoCAD Objects

You can use AutoCAD objects like closed polylines or rectangles to generate a space that is deducted from an associative space. You could do this for example to represent construction spaces or otherwise unavailable areas. Since AutoCAD objects cannot be classified to control their behavior, the following standard behavior is applied to enclosed deducted spaces formed by AutoCAD objects in BOMA:

Net Area

The net boundaries will be created inside of the wall.

Usable Area

When calculating exterior walls, the usable boundaries will be created inside the window glass if the window height is larger or equal to 50% of the space ceiling height. The usable boundaries will be created inside of the wall if the window height is smaller than 50% of space ceiling height.

Usable Area (Space Type_BOMA: MVP)  
Adjacent Spaces Boundary
Office, Store, BCA, FCA Measured from outside face of wall
MVP Measured from centerline of wall

Usable Area (Space Type_BOMA: FCA)  
Adjacent Spaces Boundary
Office, Store, BCA Measured from outside face of wall
FCA Measured from centerline of wall
MVP Measured from inside face of wall

Usable Area (Space Type_BOMA: Store Area)  
Adjacent Spaces Boundary
Street frontage Measured from outside face of wall
Office, Store, BCA Measured from centerline of wall
MVP, FCA Measured from inside face of wall

Usable Area (Space Type_BOMA: Office Area)  
Adjacent Spaces Boundary
FCA, MVP Measured from inside face of wall
Office, Store, BCA Measured from centerline of wall

Usable Area (Space Classification: BCA)  
Adjacent Spaces Boundary
FCA, MVP Measured from inside face of wall
Office, Store, BCA Measured from centerline of wall

Gross Area

The gross boundaries will be created to the outside face of the wall if there is no adjacent space or the adjacent space is street frontage.

The gross boundaries will be created to the centerline of the wall if there is an adjacent space other than street frontage/exterior.