Space / Space Inventory

Calculating Rentable Area According to BOMA 2017 Methods A and B

In 2017, BOMA released a document entitled "BOMA 2017 for Office Buildings." The main goals of the document are:

To calculate rentable area, the document utilizes a few terms that are not part of the basic Archibus space vocabulary, such as Base Building Circulation, Occupant Area, and Service and Amenity Areas. However, one can use Archibus to calculate rentable area according to BOMA 2017 by mapping the BOMA 2017 terms to Archibus terms, and then performing calculations in Archibus. See Mapping BOMA and IFMA Terminology to Archibus

In order to use the BOMA 2017 method, you must use the System / Archibus Administrator - Application Configuration / Configure Application Parameters task to set the CalculateBOMARentableArea application parameter, which directs the Update Area Totals to calculate BOMA-compatible rentable area. Set this to 2017A to use BOMA 2017 Method A, 2017B to use BOMA 2017 Method B, or "No" to skip calculating BOMA-compatible rentable area.

BOMA 2017 supports rentable exclusions, which is a category of space that is within interior gross area but excluded from rentable area. For example, areas such as occupant storage areas in the basement, a “public colonnade”, and parking are considered to be rentable exclusions. With BOMA 2017 both rentable exclusions and vertical penetration categories are excluded from rentable area.

Note: Beginning with Archibus V.24.1, Archibus supports the BOMA 2017 methods. The BOMA 2017 A and B Methods replace the BOMA 2010 A and B Methods.

Note: BOMA 2017 uses the Area Rentable BOMA and Rentable Exclusions database fields to store BOMA-specific values.

Note: According to bullet 6 in https://www.boma.org/BOMA/BOMA-Standards/BOMA_Floor_Measurement_Standards/Office_Buildings.aspx, any vertical penetration area on the lowest level can be treated as rentable area, though openings in the floor are not included in rentable area. Therefore, you can assign this type of space a room category that designates it as service area.

Calculating Rentable Area Using Method A

One of the goals of Method A is to determine a Rentable Area by proportionally allocating shared Service and Amenity Areas to occupants using multiple load factors: one for each floor and one for shared spaces that serve the building. Method A tends to lower load factors on single-tenant floors; also, load factors are more likely to change when floors are reconfigured.

The following table illustrates equivalent terminology between BOMA 2017 and Archibus for measured spaces and, in some cases, for calculated spaces where the BOMA 2017 and Archibus calculations are equivalent. It also defines the calculations required to arrive at BOMA 2017 calculated spaces.

BOMA 2017 Method A Term Calculated or Measured? Archibus Equivalent (for measured spaces) BOMA 2017 Method A Calculation (for calculated spaces)
Boundary Area (IPMS2) Measured Internal Gross Area
Rentable Exclusions Measured See the table in Mapping BOMA and IFMA Terminology to Archibus. This is a Super Category of “Other Area”, where Calculations Used In is set to “All Totals”  
Floor Rentable Area Calculated Int. Gross Area – Total Vert. Pen. Area – Total Rentable Exclusions Int. Gross Area – Total Vert. Pen. Area – Total Rentable Exclusions
Tenant Area (IPMS2) Measured Sum of all room areas that are exclusively used by a tenant. In addition to office space, this can be secondary circulation space or even exclusively used service areas. There are no formal categorizations of this space, other than it doesn’t belong to any other category of measured space listed here. That is, it consists of rooms with categories where the Super Category is either Usable Area or Service Area, it is not prorated, and it is not category TENANT ANCIL.  
Tenant Ancillary Area Measured Sum of all room area where the room’s category is TENANT ANCIL. Examples include parts of a corridor system that provide exclusive passage to specific occupants, and interior door setbacks.  
Occupant Area Calculated Sum of Tenant Area and Tenant Ancillary Area
Building Amenity Area Measured Sum of all room area where the room category’s Super Category is set to “Usable Area” and room’s prorate is set to BUILDING.  
Floor Usable Area Calculated   Sum of Occupant Area and Building Amenity Area
Building Service Area Measured Sum of all room areas where the room category's Super Category is set ot "Service Area" and the room's prorate is set to BUILDING.  
Floor Service Area Calculated This may be equivalent to a sum of room areas where the room category’s Super Category is set to “Service Area” and room’s prorate is set to FLOOR. Floor Rentable area, minus Floor Usable Areas, minus Building Service Area
Floor Allocation Ratio Calculated   Sum of Floor Usable Area and Floor Service Area, divided by Floor Usable Area. This is calculated per floor
Floor Allocation Calculated   Product of Occupant Area and Floor Allocation Ratio
Building Amenity & Service Area Calculated   Sum of Building Service Area and the product of Building Amenity Area and Floor Allocation Ratio
Building Allocation Ratio Calculated   For the entire building, the sum of Floor Rentable Area, divided by the difference between Floor Rentable Area and Building Amenity & Service Area. This is calculated for the entire building
BOMA Rentable Area Calculated   The product of Floor Allocation and Building Allocation Ratio
Load Factor A Calculated   Rentable Area divided by Occupant Area

Calculating Rentable Area Using Method B

One of the goals of Method B is to determine a Rentable Area by proportionally allocating shared Service and Amenity Areas along with Base Building Circulation to occupants using a single load factor. This occurs by using all shared space in the building to arrive at the load factor. Method B tends to increase load factors on single-tenant floors; also, load factors are less likely to change when floors are reconfigured.

The following table illustrates equivalent terminology between BOMA 2017 Method B and Archibus for measured spaces and, in some cases, for calculated spaces where the BOMA 2017 and Archibus calculations are equivalent. It also defines the calculations required to arrive at BOMA 2017 calculated spaces.

BOMA 2017 Method B Term Calculated or Measured? Archibus Equivalent (for measured spaces) BOMA 2017 Method B Calculation (for calculated spaces)
Boundary Area (IPMS2) Measured Internal Gross Area
Rentable Exclusions Measured See the table in Mapping BOMA and IFMA Terminology to Archibus. This is a Super Category of “Other Area”, where Calculations Used In is set to “All Totals”  
Floor Rentable Area Calculated Int. Gross Area – Total Vert. Pen. Area – Total Rentable Exclusions Int. Gross Area – Total Vert. Pen. Area – Total Rentable Exclusions
Tenant Area Measured Sum of all room areas that are exclusively used by a tenant. In addition to office space, this can be secondary circulation space or even exclusively used service areas. There are no formal categorizations of this space, other than it doesn’t belong to any other category of measured space listed here. That is, it consists of rooms with categories where the Super Category is either Usable Area or Service Area, it is not prorated, and it is not category TENANT ANCIL or BASE BL CIRC. Note for Method B this is not equivalent to IPMS 3 because Base Building Circulation may encroach on this area.  
Tenant Ancillary Area Measured Sum of all room area where the room’s category is TENANT ANCIL. Examples include parts of a corridor system that provide exclusive passage to specific occupants, and interior door setbacks.  
Occupant Area Calculated Sum of Tenant Area and Tenant Ancillary Area
Base Building Circulation Measured Sum of all room area where the room category’s Super Category is set to “Service Area” and room’s prorate is set to BAS BL CIRC.  
Service and Amenity Area Calculated This may be equivalent to a sum of room areas where the room category’s Super Category is set to “Service Area” or "Usable Area" and room’s prorate is set to FLOOR. Floor Rentable area, minus Occupant Area, minus Base Building Circulation
Load Factor B Calculated Sum of all room areas where the room category's Super Category is set ot "Service Area" and the room's prorate is set to BUILDING. For the entire building, the sum of Floor Rentable Area, divided by Occupant Area. This is calculated for the entire building
BOMA Rentable Area Calculated This may be equivalent to a sum of room areas where the room category’s Super Category is set to “Service Area” and room’s prorate is set to FLOOR. The product of Occupant Area and Load Factor B