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Turner Drake & Partners Ltd.
6182 North Street
Halifax, N.S.
B3K 1P5

Tel.: (902) 429-1811
Toll Free: (800) 567-3033
Fax.: (902) 429-1891

Suite 221
12 Smythe Street
Saint John, N.B.
E2L 5G5
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109 Richmond Street
Charlottetown, P.E.
C1A 1H7
Tel.: (902) 368-1811

35 York Street
St. John's, N.L.
A1C 5M3
Tel.: (709) 722-1811

4th Floor
111 Queen Street East
Toronto, ON.
M5C 1S2
Tel.: (416) 504-1811

E-Mail: tdp@turnerdrake.com
Internet: www.turnerdrake.com

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Lasercad® (Space Measurement)

Office Standard Method of Measurement

The Building Owners and Managers Association (BOMA) Standard Method of Measurement is used to measure space in office buildings. The process of determining the Rentable Area for each tenant space, as stated by BOMA, consists of several steps:

  1. Calculate the Interior Gross Area of each floor of the building, employing the concepts of finished surface and dominant portion. BOMA defines Interior Gross Area as "the area, measured in a horizontal plane, of a floor level of a building that is circumscribed by the Interior Gross Area boundary, without deductions for columns or projections necessary for the building". There are some exceptions but essentially the Interior Gross Area boundary is the interior face of the exterior wall ... unless the floor fronts onto a Public Pedestrian Thoroughfare, in which happy event the boundary is the exterior face of the exterior wall (again with some exceptions).

  2. Calculate the area of all Major Vertical Penetrations (defined as "a floor opening in excess of 1 square foot that serves vertical building systems or vertical occupant circulation functions". It includes stairwells, elevator shafts, flues, pipe shafts, ventilation ducts and their enclosing walls) as well as enclosed parking areas and Occupant Storage units. Subtract these from the Interior Gross Area to arrive at a Preliminary Floor Area.

  3. Calculate the area of all Occupant Areas (tenant units), Building Amenity Areas, and Building Service Areas.

  4. Determine the Floor Service & Amenity Areas by deducting from the Preliminary Floor Area all Occupant, Building Amenity, and Building Service Areas.

  5. The Floor Service & Amenity Areas are allocated to each tenant by multiplying the various Occupant Areas by the R/U Ratio to arrive at Occupant and Allocated Area. [The R/U Ratio is the factor which distributes the Floor Service and Amenity Areas to the various occupants on each floor on a proportionate basis. The R/U Ratio = (Occupant Area + Building Amenity Area + Floor Service and Amenity Areas) ÷ (Occupant Area + Building Amenity Area)].

  6. The Building Service and Amenity Areas are then allocated to each tenant through the application of the R/O Ratio to arrive at their Rentable Area. [The R/O Ratio is the factor which distributes the Building Service and Amenity Areas to all the occupants of the building on a proportionate basis. The R/O Ratio = (Total Preliminary Floor Area) ÷ (Total Occupant and Allocated Areas)].

Frequently Asked Questions:

  1. Q: Is atrium space measured by the Standard?

    A: Atrium space above the main lobby floor does not constitute Rentable Area. It is empty space and is treated as a void in the floor (i.e. it is excluded from the Interior Gross Area). The base of the atrium, however (i.e. the finished floor) is measured.

  2. Q: How are "enclosing walls" defined in conjunction with Major Vertical Penetrations? What about the floor of the stair tower or the elevator pits of the elevator shaft?

    A: The term "enclosing walls" refers to those walls required by the building code, and not to the architectural or decorative treatments of those walls. The floor of a stair tower and the pits of the elevator shaft, when found inside the enclosing walls, are part of the Major Vertical Penetration. However, if an area is not within the enclosing walls (such as a storage room under the stair tower), the area is part of the Rentable Area.

  3. Q: Are areas outside the fire resistance enclosure of a Major Vertical Penetration considered part of that penetration? For example, plumbing chases behind restrooms?

    A: No. Walls enclosing the major vertical penetration, which are required by the building code, are part of the penetration. Additional walls outside these enclosing walls are not considered part of the penetration and are not deducted from Rentable Area.

  4. Q: Are "areas of refuge" (mainly a feature of Canadian buildings) deducted as Major Vertical Penetrations?

    A: If the area of refuge is not isolated from the stairwell, then it is part of the Major Vertical Penetration and is deducted as such. If the area of refuge is isolated from the stairwell with its own set of doors, then it is part of the Preliminary Floor Area and is distributed to each Occupant Area through the application of the R/U Ratio.

  5. Q: Can a mechanical room serving tenants on an above-ground floor be part of Building Service Area?

    A: Yes, if it is not already part of a Floor Service or Amenity Area.

  6. Q: How are door setbacks treated under the Standard?

    A: Entrances and exits for Occupant, Service and Amenity Areas are often recessed from the corridor to accommodate door swings or for accent/variation to a corridor wall. When entrances or exits are set back from the typical wall line of the corridor, the boundary line does not follow the door setback but continues as if the recess had not occurred.

  7. Q: On an above ground floor, can a corridor that is ordinarily a Floor Service Area be assessed to a particular tenant if it provides the only access to their space?

    A: Yes. Corridor space comprising a recessed entrance or a corridor used solely by a specific tenant is allocated to that tenant.

  8. Q: How is storage space measured under the Standard?

    A: If the space is for the sole use of a tenant it is considered an Occupant Storage area. It is measured initially as any other tenant space but does not receive a gross-up for common areas. If the storage space serves the building at large, it is considered a Building Service Area and is allocated to the various building occupants through the R/O ratio.

  9. Q: Is a courtyard included in Building Amenity Area if it is enclosed by four sides but not a roof?

    A: "Fully enclosed" refers to an enclosed space where environmental conditions are maintained by a heating, ventilating and air conditioning system; so there must be a roof in order for the courtyard to be fully enclosed.

  10. Q: Are an exercise club and restaurant part of Building Amenity Areas if they serve the entire building?

    A: No; these areas represent rent-paying tenants; so while they do provide a service to the entire building (indeed to any paying customer), they are Occupant Areas rather than Building Amenity Areas. However, if these areas were available for all tenants to use as part of their lease, then they would be considered Building Amenity Areas instead.

  11. Q: In an office complex, would mechanical areas located in one building, but which serve others as well, be considered Building Service Areas? What about underground corridors that link one building with another?

    A: Although the Standard does not deal specifically with building complexes, it does state that it would be a reasonable adaptation to consider the entire project as one building and to allocate the common corridors and building mechanical areas using the R/O Ratio.

  12. Q: On a single tenant floor, are the elevator lobby and restrooms considered Occupant Area?

    A: The elevator lobby is considered part of the Occupant Area; however the washrooms are considered to be Floor Service Areas.

  13. Q: If a private stairway is built between two floors occupied by one tenant, is that stairway part of Rentable Area or is it deducted as a Major Vertical Penetration?

    A: Any vertical penetrations built for the private use of a tenant occupying space on more than one floor are counted as Rentable Area. The stairway would also be part of the Occupant Area of the tenant.

  14. Q: If a tenant expands its Occupant Area, do the (Floor) R/U Ratio and (Building) R/O Ratio change as a result - meaning that each tenant's Rentable Area would change?

    A: It depends where the expansion takes place. If the tenant merely expands into an adjacent unit then the ratios will remain unchanged. If the tenant expands into a Service or Amenity Area then it may affect the R/U Ratio, the R/O Ratio, or both.

  15. Q: Is parking ever counted as Rentable Area?

    A: No, the Standard excludes parking space from Rentable Area.

  16. Q: Does the Standard measure retail units if they exist within an office building?

    A: Yes, the Standard treats retail units in a similar manner to the "Store Area" methodology provided in the 1996 Standard. When a unit has frontage to a "Public Pedestrian Thoroughfare" such as a sidewalk, the exterior wall is included within the Occupant Area calculation for that tenant.

  17. Q: If a retail store is on a corner, is the measurement taken to the building line on both sides? Does it matter whether entrances to the space are located on both sides?

    A: All exterior walls fronting a Public Pedestrian Thoroughfare are included in the Usable Area of that unit; hence it is possible for a square building to meet this condition on every one of its sides. It does not matter if the sides are at the same floor level or if they have entrance doors to the unit.

  18. Q: Should ground floor spaces that have separate entrances and have no access to ground floor lobbies still receive a "gross-up" for those areas.

    A: Yes, all tenant spaces within a building should be treated equally. Therefore tenant spaces with separate entrances and no access to ground floor lobbies are treated in the same manner as tenants who do have access to the ground floor lobby.

  19. Q: How are columns treated by the Standard? Are they deducted from area calculations?

    A: No deductions are made for floor space occupied by columns and all measurements are taken as though the columns do not exist. Thus, where two walls meet a column the measurement will continue through the column to the imaginary point at which the walls would meet if the column were not present.

  20. Q: How is the boundary of a tenant space defined?

    A: The area of a tenant space is taken to the centre line of walls separating the unit from adjacent tenant spaces or Amenity Areas, to the inside face of walls bordering Major Vertical Penetrations and Service Areas, and to the dominant portion of exterior walls.

  21. Q: Are mezzanines measured by the Standard?

    A: Permanent mezzanines are measured by the Standard with the area of the mezzanine being included as part of the floor area immediately below. Temporary mezzanines (which tend to be built by the tenant with the intention of being removed or relocated at a later date) are not measured by the Standard. The usefulness of a mezzanine is not addressed by the Standard, and is better left for lease negotiations between Landlord and Tenant. Varying lease rates are common in the market using such criteria as location on the floor, proximity to the elevator lobby, windows, views, heights in the building, and the usefulness of a particular space.

  22. Q: Does the Standard measure space in below-ground floors?

    A. Yes, except for those areas specifically excluded by the Standard, such as parking areas.

  23. Q: Is Gross Building Area an appropriate way to measure a single occupant building?

    A: Gross Building Area refers to the total enclosed area of a building. Since single occupant buildings will often need to be compared to multi-occupant buildings, building Rentable Area is the preferred measurement to use. Gross Building Area is not measured by the Standard and should only be used in instances where all parties agree.

  24. Q: Does the Standard provide for the measurement of warehouse or industrial space? Does it cover a shopping centre or strip mall?

    A: No, the Standard is intended to apply specifically to the measurement of office buildings. No provision is currently made for measuring any other type of building.

  25. Q: Does BOMA 'certify' space measurement firms or instruments?

    A: Neither BOMA nor the American National Standards Institute (ANSI) certifies, approves, or endorses any space measurement firm or measurement device.