ASTM E1836/E1836M-09(2016)

Standard Practice for Building Floor Area Measurements for Facility Management

SIGNIFICANCE AND USE
4.1 This practice can be used to facilitate comparison of areas that have been measured but it does not specify what measurements must be conducted.  
4.2 This practice can be used in space programming and forecasting of space requirements.  
4.3 This practice can be used to classify areas for internal cost accounting purposes.  
4.4 This practice can be used to compare space use between organizations.
SCOPE
1.1 This practice provides a definitive procedure for measuring and classifying floor area in buildings for use in facility management, specifying occupant requirements, space planning, and for strategic facility planning.  
1.2 This practice specifies the sequence in which to measure floor area.  
1.3 This practice is applicable to owned, rented, and leased buildings.  
1.4 Use Annex A1 to measure floor area in office facilities. The measurement practice in Annex A1 may also be suitable for use in other functional types of building which include offices, such as research, laboratory, or manufacturing buildings and building-related facilities.  
1.5 The practice in Annex A1 is not intended for use in lease negotiations with owners of commercial office buildings or related properties. For that purpose, refer to the American National Standard published by the American National Standards Institute under the designation ANSI/BOMA Z65.1–1996 and commonly known as the ANSI-BOMA standard.  
1.6 This practice is not intended for and not suitable for use for regulatory purposes, fire hazard assessment, and fire risk assessment.  
1.7 This practice was developed for use within North America and includes some rules comparable to ISO 9836 Performance Standards in Building—Definition and Calculation of Area and Space Indicators.  
1.8 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Published
• Publication Date: 29-Feb-2016
• ICS: 35.240.67 - IT applications in building and construction industry
• ICS: 91.140.01 - Installations in buildings in general
• Technical Committee: E06 - Performance of Buildings
• Drafting Committee: E06.25 - Whole Buildings and Facilities

Relations

• Replaces: ASTM E1836/E1836M-09e1 - Standard Practice for Building Floor Area Measurements for Facility Management
• Effective Date: 01-Mar-2016
• Refers: ASTM E631-15 - Standard Terminology of Building Constructions
• Effective Date: 01-Mar-2015
• Refers: ASTM E631-14 - Standard Terminology of Building Constructions
• Effective Date: 01-Nov-2014
• Refers: ASTM E2619/E2619M-09e1 - Standard Practice for Measuring and Calculating Building Loss Features That Take Up Floor Area in Buildings
• Effective Date: 01-Apr-2009
• Refers: ASTM E631-06 - Standard Terminology of Building Constructions
• Effective Date: 01-Jun-2006
• Refers: ASTM E631-93a(1998)e1 - Standard Terminology of Building Constructions
• Effective Date: 28-Jul-2000
• Referred By: ASTM E1694-22 - Standard Classification for Serviceability of an Office Facility for Special Facilities and Technologies
• Effective Date: 01-Mar-2016
• Referred By: ASTM E2514-15(2020) - Standard Practice for Presentation Format of Elemental Cost Estimates, Summaries, and Analyses
• Effective Date: 01-Mar-2016
• Referred By: ASTM E2166-16(2023) - Standard Practice for Organizing and Managing Building Data
• Effective Date: 01-Mar-2016
• Referred By: ASTM E1664-19 - Standard Classification for Serviceability of an Office Facility for Layout and Building Factors<rangeref></rangeref >
• Effective Date: 01-Mar-2016
• Referred By: ASTM E2619/E2619M-17 - Standard Practice for Measuring and Calculating Building Loss Features That Take Up Floor Area in Buildings
• Effective Date: 01-Mar-2016

Overview

ASTM E1836/E1836M-09(2016): Standard Practice for Building Floor Area Measurements for Facility Management establishes a standardized methodology for measuring and classifying building floor areas. Developed by ASTM International, this practice brings clarity and consistency to floor area reporting in facility management, enhancing the comparability and reliability of building data across organizations and sectors.

The standard applies to owned, rented, and leased buildings, providing a procedure valuable for facility managers, space planners, and organizations involved in space management, chargeback, and strategic facility planning. It is specifically designed for North American contexts but incorporates principles comparable to those in ISO 9836.

Key Topics

• Definitions and Classifications: Provides clear definitions for terms such as assignable area, usable area, plannable area, gross floor area, amenity area, service area, restricted areas, and more. This common language improves communication among stakeholders and ensures accurate reports.
• Measurement Procedure: Outlines the sequence and boundaries for floor area measurements, specifying that all measurements must be taken along the horizontal plane to points where floors and walls intersect. Special considerations are given for sloped floors, stair landings, and various encroachments.
• Application to Various Building Types: While the primary focus is on office facilities, the practice is also applicable to buildings with mixed functions, such as laboratories, research, and manufacturing facilities, as well as their ancillary spaces.
• Scope and Limitations: The standard is intended for internal facility management, space planning, and cost accounting, and is not to be used in regulatory assessments, fire safety calculations, or lease negotiations with building owners. For lease negotiations, the ANSI/BOMA Z65.1 standard is recommended.

Applications

ASTM E1836/E1836M-09(2016) is a practical tool in the following areas:

• Facility Management: Standardizing floor area measurements allows facility managers to make informed decisions about space utilization, maintenance, and operations.
• Space Planning and Programming: Accurate and consistent area data is critical in forecasting space needs and programming future requirements.
• Cost Allocation: Defines categories useful in classifying building areas for internal cost accounting and chargeback to occupants or departments.
• Benchmarking and Comparison: Facilitates objective comparisons of space use between organizations or departments, supporting continuous improvement and efficient space management.
• Reporting and Record Keeping: Provides procedures for transparent and repeatable area reporting, supporting audits, regulatory submissions, and internal strategy development.
• Software Integration: The definitions and processes support integration with Computer Aided Facilities Management (CAFM) and Building Information Modeling (BIM) systems, promoting automation in floor area calculation and reporting.

Related Standards

For comprehensive facility management, users may reference:

• ANSI/BOMA Z65.1: Standard Method for Measuring Floor Area in Office Buildings, specifically for lease negotiations.
• ASTM E2619/E2619M: Practice for Measuring and Calculating Building Loss Features that affect floor area.
• ISO 9836: Performance Standards in Building - Definition and Calculation of Area and Space Indicators, offering internationally aligned principles.
• ASTM E631: Terminology of Building Constructions, for standard definitions used in building industry practices.

Conclusion

Implementing ASTM E1836/E1836M-09(2016) in your facility management program promotes accurate, fair, and transparent management of space resources. By using standardized procedures for floor area measurements, organizations can optimize space utilization, streamline internal accounting, and support strategic planning with reliable building data. For facility managers, space planners, and cost accountants, adherence to this standard is a cornerstone of best practice in building and facility management.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E1836/E1836M − 09 (Reapproved 2016)
Standard Practice for
Building Floor Area Measurements for Facility Management
ThisstandardisissuedunderthefixeddesignationE1836/E1836M;thenumberimmediatelyfollowingthedesignationindicatestheyear
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope each system may not be exact equivalents; therefore, each
system shall be used independently of the other. Combining
1.1 This practice provides a definitive procedure for mea-
values from the two systems may result in non-conformance
suring and classifying floor area in buildings for use in facility
with the standard.
management, specifying occupant requirements, space
1.9 This standard does not purport to address all of the
planning, and for strategic facility planning.
safety concerns, if any, associated with its use. It is the
1.2 Thispracticespecifiesthesequenceinwhichtomeasure
responsibility of the user of this standard to establish appro-
floor area.
priate safety and health practices and determine the applica-
1.3 This practice is applicable to owned, rented, and leased
bility of regulatory limitations prior to use.
buildings.
1.10 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.4 Use Annex A1 to measure floor area in office facilities.
ization established in the Decision on Principles for the
The measurement practice in Annex A1 may also be suitable
Development of International Standards, Guides and Recom-
for use in other functional types of building which include
mendations issued by the World Trade Organization Technical
offices, such as research, laboratory, or manufacturing build-
Barriers to Trade (TBT) Committee.
ings and building-related facilities.
1.5 ThepracticeinAnnexA1isnotintendedforuseinlease
2. Referenced Documents
negotiations with owners of commercial office buildings or
2.1 ASTM Standards:
related properties. For that purpose, refer to the American
E631 Terminology of Building Constructions
National Standard published by the American National Stan-
E2619/E2619M Practice for Measuring and Calculating
dards Institute under the designation ANSI/BOMA
Building Loss Features That Take Up Floor Area in
Z65.1–1996 and commonly known as the ANSI-BOMA stan-
Buildings
dard.
2.2 ANSI Standard:
1.6 This practice is not intended for and not suitable for use
ANSI/BOMA Z65.1–1996 Standard Method for Measuring
for regulatory purposes, fire hazard assessment, and fire risk
Floor Area in Office Buildings
assessment.
2.3 ISO Standards:
1.7 This practice was developed for use within North
ISO 9836 Performance Standards in Building—Definition
America and includes some rules comparable to ISO 9836
and Calculation of Area and Space Indicators
Performance Standards in Building—Definition and Calcula-
tion of Area and Space Indicators.
1.8 The values stated in either SI units or inch-pound units
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
are to be regarded separately as standard. The values stated in
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
This practice is under the jurisdiction of ASTM Committee E06 on Perfor- the ASTM website.
mance of Buildings and is the direct responsibility of Subcommittee E06.25 on Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
Whole Buildings and Facilities. 4th Floor, New York, NY 10036, http://www.ansi.org.
Current edition approved March 1, 2016. Published June 2016. Originally Available from International Organization for Standardization (ISO), ISO
ɛ1
approvedin1996.Lastpreviouseditionapprovedin2009asE1836/E1836M – 09 . Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,
DOI: 10.1520/E1836_E1836M-09R16. Geneva, Switzerland, http://www.iso.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1836/E1836M − 09 (2016)
3. Terminology 3.2.6.1 Discussion—Areas which are not enclosed, such as
patios and balconies, are not part of exterior gross area.
3.1 Definitions:
Cornices, pilasters, buttresses, and so forth that extend beyond
3.1.1 floor, n—in a building, supporting structure (generally
the wall face are disregarded. The exterior gross area of a
horizontal) and constituting the bottom level of each story.
6 basement space includes the area measured to the outside face
E631
of basement or foundation walls.
3.1.2 For standard definitions of additional terms applicable
3.2.7 finished surface, n—inside face of a wall, window,
to this practice, see Terminology E631.
ceiling, or floor that is provided as part of the base building for
3.2 Definitions of Terms Specific to This Standard:
the general use of occupants, excluding the thickness of any
3.2.1 amenity area, n—portion of a building that provides a
special surfacing materials applied to meet the particular needs
conveniencetoanoccupantoroccupantsofabuildingorgroup
of specific occupants.
of buildings.
3.2.1.1 Discussion—In general, occupancy codes and regu-
3.2.8 floor area, n—area in the horizontal plane of the
lations do not govern these areas, although there may be codes
bottom level of a story or stories in a building.
and regulations that relate to their specific uses.
3.2.9 interior encroachment, n—base building element that
3.2.2 assignable area, n—portion of the plannable area on a
is located inside a building, not on an outer wall, and that
floor that can be assigned to occupant groups or functions.
prevents the use of the floor area for furniture, equipment,
3.2.3 building, n—contiguous and undivided shelter com- circulation, or other occupant function.
prising a partially or totally enclosed space, erected by means
3.2.10 interior gross area, n—portion of the floor(s) that is
of a planned process of forming and combining materials.
totally enclosed within the dominant portion.
3.2.4 dominant portion, n—the inside surface of the outside
3.2.11 interior parking, n—totally or partially enclosed area
wall, as defined in ANSI/BOMA Z65.1–1996.
that is within a building and that is normally used to circulate
3.2.4.1 Discussion—ANSI/BOMA Z65.1–1996 specifies
and station vehicles.
when to consider the inside surface of the window glass as the
dominant portion to measure to, and when to measure to some 3.2.12 interstitial floor area, n—area of load-bearing sur-
other part of the outside wall. faces located above or below occupied building floors that is
not available for general occupancy.
3.2.5 excluded area, n—portion of a floor within a building
3.2.12.1 Discussion—Interstitial floor area is often not
that is not suitable for occupancy by people or equipment.
available for occupancy due to inadequate clear headroom.
3.2.5.1 Discussion—While excluded areas may meet the
Typically interstitial floor area contains building mechanical or
criteria of adequate clear headroom there is owner/landlord
electrical systems predominantly serving adjacent floors or to
documentation which indicates that these areas are to be
provide access to such systems.
excluded from floor interior gross area calculations. Examples
of excluded areas include but are not limited to unfinished attic
3.2.13 major vertical penetration, n—opening in a floor that
areas, attic areas with obstructed access, damp or flooded 7
serves a building or system distribution function.
basements, and confined areas requiring permits for entry.
3.2.14 matrix, n—a grid-like array of elements.
Areas temporarily unusable due to flood, fire damage, con-
struction or renovation activity are not excluded areas.
3.2.15 occupant, n—of a building, one who has certain legal
3.2.6 exterior gross area, n—the area of the floor measured rights to or legal control over the premises occupied.
to the outside face of the walls that enclose the floor(s) of the
3.2.15.1 Discussion—An occupant may be a tenant in a
building.
building or the owner of a building.
3.2.16 occupant void area, n—opening in a floor created for
the specific benefit of an occupant.
Certain definitions of terms in this practice were agreed in 2007 by a Working
Group established jointly by the Building Owners and Managers Association 3.2.16.1 Discussion—Examples of occupant void areas are
(BOMA) International and the International Facility Management Association
privateelevators, communicatingstairswithintenant premises,
(IFMA). Certain terms were derived from referenced ASTM standards or from
and the opening in the floor above in tenant rooms that are
referenced ANSI standard, or from published IFMA documents. Ownership of
multi-story in height.
copyright to specific terms is indicated by footnotes. Certain terms are quoted from
other ASTM standards, in which case the ASTM source is identified at the end of
3.2.17 perimeter encroachment, n—base building element
the definition.
or restricted area that is located inside the dominant portion of
Information such as this, inserted at the end of a definition, gives the number
of a standard from which this definition was quoted or derived. If a number follows
a building on the outer wall and that prevents the use of the
adashattheendofthisinformation,itindicatestheyearofapprovalofthestandard.
floor area for furniture, equipment, circulation, or other occu-
Copyright is shared with BOMA International.
pant function.
In the 1996 edition, which is copyright by BOMA, the dominant portion is
defined as the inside face of the portion of the wall which is window glass where it
is more than 50 % of the vertical distance from finished floor to finished ceiling, and
elsewhere as the inside face of the outside wall, or of a pilaster or column attached
to the outside wall where they occur. Note that the reader is cautioned that the ASTM copyright is shared with BOMA International.
dominant portion is not defined as a part of this ASTM standard. Instead, New term for which copyright is shared by ASTM and BOMA International.
ANSI/BOMA Z65.1–1996 is developed by and subject to the authority of BOMA Oxford English Dictionary, 2nd ed., Oxford University Press, 1989, s.v.
International, which may change it from time to time at its sole option. “matrix.”
E1836/E1836M − 09 (2016)
3.2.18 plannable gross area, n—portion of a floor that is 3.2.26 usable area, n—portions of a building that can be
totally enclosed within the interior face of perimeter encroach- classified as tenant area or amenity area.
ments at the floor plane and where there are no perimeter
3.2.27 void area, n—absence of a floor inside the dominant
encroachments enclosed at the inside finished surface of the
portion where a floor might otherwise be expected or
exterior walls.
measured, that is typically in the plane of the upper floors of
3.2.19 polygon, n—closed plane figure made up of several multi-story atria or lobbies, light wells, auditoria or the area
line segments that are joined together. adjacent to a partial-floor mezzanine.
3.2.20 primary circulation area, n—minimum path on a
4. Significance and Use
floor for access to egress stairs, elevator lobbies, toilet rooms,
refuge areas, building lobbies, and entrances.
4.1 This practice can be used to facilitate comparison of
areas that have been measured but it does not specify what
3.2.21 restricted area, n—portion of floor area that would
measurements must be conducted.
normally be available for use by an occupant, but the occupant
is limited from using the area, either by regulatory authority or
4.2 This practice can be used in space programming and
from a governing document.
forecasting of space requirements.
3.2.22 restricted headroom, n—large portion of a floor that
4.3 This practice can be used to classify areas for internal
does not have sufficient clear, unobstructed headroom to
cost accounting purposes.
conform to local building codes or that has headroom less than
4.4 This practice can be used to compare space use between
that required for occupancy.
organizations.
3.2.22.1 Discussion—Restricted headroom is primarily in-
tended to exclude large areas such as low attics and crawl-
5. Basis of Practice
spaces from being defined as “floors.” It also establishes, in a
sloped ceiling attic or sloped exterior wall, where the effective
5.1 The basis for classification of floor area measurements
outer wall is located. Restricted headroom does not apply to for certain functional types of building is contained in Annex
reduced or no headroom conditions (that is, walls, columns, A1.
stairs, door headers, limited piping, railings, alcoves, and so
NOTE 1—In the future, additional annexes are expected to be added to
forth) typically found on a floor, unless they are part of an
this practice to contain the classifications for floor area measurements in
overall restricted headroom condition.
other functional types of building and to compare measurements of floor
area for different purposes or from different countries.
3.2.23 secondary circulation area, n—portion of a floor
required for access to some subdivision of a floor, that does not
6. Measurement Procedure and Report
serve all occupants on a floor and that is not defined as primary
6.1 AnnexA1providesaprocedureformeasuringfloorarea
circulation area.
and for reporting such measurements for certain functional
3.2.24 service area, n—portion of a building that provides
types of building for those purposes stated in Section 1.
services that enable occupants to work in a building.
3.2.24.1 Discussion—Service areas make it possible to ac-
6.2 When reporting floor area, measured in accordance with
commodate occupants within a building without violating
the procedure in Annex A1, note any exceptions to the
existing building codes and occupancy controls, or both.
prescribed method. Where possible, also assess the extent of
variation and state as an estimate.
3.2.25 unassigned area, n—portion of the plannable area on
a floor that is not assigned to occupant groups or functions.
6.3 If Practice E2619/E2619M is also used, findings from
3.2.25.1 Discussion—Unassigned area includes all plan-
that practice may be included in the report of building floor
nable area that cannot be classified as either assignable area, or
area measurement, but the area of building loss features shall
restricted area, or occupant void, or interior encroachment, or
be clearly identified.
secondary circulation. Examples are: (1) small areas between
furniture panels and columns where furniture does not fit; and
7. Keywords
(2) area set aside to install future workstation or other
7.1 area; building; building floor area; facility; facility
functions.
management; floor area; measurement; occupant requirement
Mathway Math Glossary, s.v. “polygon,” http://www.mathway.com/
glossary.aspx?section=p.
13 14
Terms from BOMA and ASTM standards were used as the starting point to Term in the BOMA standard used as the starting point to develop this term.
develop this term. The copyright of this term is shared by ASTM and BOMA. BOMA shares the copyright with ASTM.
E1836/E1836M − 09 (2016)
ANNEXES
(Mandatory Information)
A1. PRACTICE FOR MEASUREMENT IN OFFICE FACILITIES AND RELATED FUNCTIONAL TYPES OF BUILDINGS
SUCH AS RESEARCH, LABORATORY, AND MANUFACTURING BUILDINGS AND BUILDING-RELATED FACILITIES
A1.1 Introduction A1.4 Rules for Measurement
A1.4.1 Measurements shall include only floor areas that are
A1.1.1 The purpose of Annex A1 is to provide consistent
totally enclosed within a building. Climate conditions and
terms, definitions, and measurement procedures for floor area
construction practices will dictate the degree of weather
measurements to facilitate comparison of measurements
tightness typical for exterior walls in a local area. Basements,
among different organizations and for financial chargeback.
enclosed porches, penthouses, mechanical equipment rooms,
A1.2 Scope
lobbies, mezzanines, corridors, interior parking, and enclosed
loadingdocksareincluded.Spacesoutsidetheexteriorwallsor
A1.2.1 Use Annex A1 to measure floor area in office
without a roof covering are not included in the floor area
facilities. This measurement practice may also be suitable for
measurement. A space, such as balcony, which has a roof or
use in other functional types of building which include offices,
ceiling but is not fully enclosed, is not included.
such as research, laboratory, or manufacturing buildings and
A1.4.2 For space planning and chargeback, measure the
building-related facilities.
plannable gross area and the various elements of floor area
A1.2.2 AnnexA1 is applicable to the measurement of space
within the plannable gross area. However, there are likely to
whether owned or leased.
be instances when additional measurements may be needed.
Therefore, elements of floor area shown in Fig.A1.1 under the
A1.2.3 Annex A1 is intended for use by facility managers
exterior gross area and the interior gross area are described to
and occupants of building and facilities. It is suitable for such
give context to the cascade of relationships from the gross
purposesasstrategicplanning,spacemanagement,andinternal
exterior to the plannable area. However, to ensure correct
chargeback to occupant organizations.
measurement of elements outside the plannable gross area will
A1.2.4 Annex A1 gives rules for measurement for use in
require using the procedures contained in ANSI/BOMA
facility management, space planning, and chargeback to occu-
Z65.1–1996.
pant units.
A1.4.3 All measurements shall be made along the plane of
A1.2.5 Annex A1 is not intended for use in lease negotia-
the floor to the points where floors and walls intersect.
tions with owners of commercial office buildings or related
A1.4.4 Inthecaseofaslopedfloormeasurethefloorareain
properties. For that purpose, refer to the American National
the horizontal plane as depicted on a floor plan.
Standard published by the American National Standards Insti-
A1.4.5 Stair landings shall not count as floor area, but as
tute under the designation ANSI/BOMA Z65.1–1996, and
part of the stair.
commonly known as the ANSI-BOMA standard.
A1.4.6 The finished surface of a wall normally consists of
A1.3 Relationships Between Categories of Floor Area
gypsum wallboard, glass, plaster, concrete, brick, or masonry
A1.3.1 This annex includes four categories of floor area: units. Special wall materials used to surface a wall are furring
Exterior Gross Area, Interior Gross Area, Plannable Gross strips, paneling or casework, tile, mirrors, and any materials
Area, and Plannable Area. (Refer to Fig. A1.1.) referred to as “wall coverings” or “window coverings” that are
applied over base building finished walls or windows.
A1.3.2 These four categories of floor area, and the elements
A1.4.7 The finished surface of an exterior window shall be
(sub-catagories of floor area) within each of these four
the glass surface that is in direct contact with the interior
categories, relate one to the other in the following ways:
environment of the building.
A1.3.2.1 Interior GrossArea is equal to Exterior GrossArea
less Dominant Portion to Exterior GrossArea, ExcludedAreas, A1.4.8 The finished surface of a floor is the top of a deck,
Interstitial Areas, Restricted Headroom Areas, and Interior typically concrete or wood, without special surfacing materials
that are applied over the base building finished floor, such as
Parking Areas.
carpeting, tile, resilient flooring, or any materials referred to as
A1.3.2.2 Plannable Gross Area is equal to Interior Gross
“floor coverings.”
Area less Perimeter Encroachments.
A1.3.2.3 PlannableAreaisequaltothesumofthefollowing
A1.4.9 The finished surface of a ceiling is typically the
areas: Restricted Areas, Interior Encroachments, Occupant underside of acoustical tile, plaster, gypsum, wallboard, or
Void Areas, Unassignable Areas, Assignable Areas, and Sec- similar surface. In the absence of a continuous ceiling surface,
ondary Circulation. measurement to the finished surface of the ceiling shall be to
E1836/E1836M − 09 (2016)
FIG. A1.1 Floor Area Relationships
the bottom of any suspended ceiling grid, or, if no ceiling grid A1.4.10 Restricted headroom is typically 2.0 to 2.3 m [6.5
exists, to the lower of [1) the underside of exposed building to 7.5 ft] or less.This category is primarily intended to exclude
structure elements or (2) the lowest general level of the bottom
large areas such as low attics and crawlspaces from being
of light fixtures (not including up-lighting), air diffusers,
defined as “floors.” It also establishes, in a sloped ceiling attic
sprinkler heads or similar base building fixtures that are
or sloped exterior wall, where the effective outer wall is
suspended below the underside of building structural elements,
located. The category of restricted headroom does not apply to
or (3) the typical ceiling height established by the intended
places with reduced or no headroom conditions (that is, walls,
building design; provided that a finished ceiling height as
columns, stairs, door headers, limited piping, railings, alcoves,
designed does not create a restricted headroom condition.
E1836/E1836M − 09 (2016)
and so forth) typically found on a floor, unless they are part of total floor area taken up with perimeter encroachments while
an overall restricted headroom condition. determining the interior gross area.
A1.4.12.2 Perimeter Encroachments—Measure the base
A1.4.11 Exterior Gross Area—Measured Elements:
building elements or restricted areas that are located inside the
A1.4.11.1 Exterior Gross to Dominant Portion—Building
dominant portion of a building on the outer wall and that
exterior gross area is the sum of the floor areas on all levels of
prevent the use of the floor area for furniture, equipment,
a building that are totally enclosed within the building. When
circulation or other occupant function. (Dominant Portion is
users of this practice also use the ANSI/BOMA standard, 15
defined in ANSI/BOMA Z65.1–1996. ) Perimeter encroach-
measure building exterior gross area to the outside face of
ments include but are not limited to: (1) window sills; (2)
exterior walls, disregarding canopies, cornices, pilasters,
building projections such as convector, baseboard heating unit,
buttresses, balconies that are not fully enclosed and that extend
radiator, or other building element that is located in the interior
beyond the wall face, and courtyards that are enclosed by walls
of a building and adjacent to a perimeter building wall that
but have no roof. A balcony that is not fully enclosed is not
prevents the use of that space for furniture, equipment,
included in the exterior gross area even if it does not extend
circulation, or other functions; (3) horizontal floor area be-
beyond the line of the outside wall face. The building gross
tween adjacent encroachments where such area is 300 mm
area of basement space includes the area measured to the
[12 in.] or less (such as the distance between a perimeter
outside face of basement or foundation walls.
column and adjacent curtain wall HVAC distribution device);
(1) If Property Line is Within a Building—If the property
(4) structural columns located on the perimeter of the building
line lies within a building wall that is common with an
or within 300 mm [12 in.] or less of the inside finished surface
adjoining building, measure the building exterior gross area to
of the perimeter wall.
the property line. If the property line does not lie within a
A1.4.12.3 Figs. A1.2-A1.5 each demonstrates how to mea-
building wall but the wall is structurally common with an
sure perimeter encroachments. Each figure shows a different
adjoining building, measure building exterior gross area to the
combination of building features at a perimeter wall.
center of the structural portion of the common wall.
A1.4.12.4 The first example in Fig.A1.2 illustrates a perim-
A1.4.11.2 Exterior Bridges and Tunnels—Exterior tunnels
eter encroachment at a windowsill. Measure the area of the
bridges and tunnels which are totally enclosed constructed
encroachment from the inside face of the dominant portion to
areas connecting two or more buildings are included in the
the inside face of the exterior building wall.
interior building gross area but are not included in the gross
A1.4.12.5 InFig.A1.3,abuildingstructurecomponentsuch
plannable area. Assign exterior bridges and tunnels to one
as a radiator protrudes into the floor area. Measure the area of
building or apportion between buildings.
the encroachment from the inside face of the dominant portion
A1.4.11.3 Excluded Areas—Measure each excluded area.
to the interior face of the protruding encroachment.
While excluded areas may meet the criteria of adequate clear
A1.4.12.6 Fig. A1.4 is an example of an encroachment due
headroom, if there is owner/landlord documentation that indi-
to a distribution system for heating, ventilating, or air condi-
cates that these areas are to be excluded from the gross interior
tioning (HVAC). Measure the area of the encroachment from
floor area calculations then measure each excluded area and
the inside face of the dominant portion to the inside face of the
deduct from the exterior gross area. Examples of excluded
HVAC radiator.
areas include, but are not limited to, unfinished attic areas, attic
A1.4.12.7 The example in Fig. A1.5 demonstrates another
areas with obstructed access, damp or flooded basements, and
typeofHVACdistributionsystem.ThisHVACsystemisatube
confined areas requiring permission for entry.Areas temporar-
on the floor that is adjacent to the wall. Measure the area of the
ily unusable due to flood, fire damage, construction, or reno-
encroachment from the inside face of the dominant portion to
vation activity are not excluded areas.
the inside face of the HVAC tube.
A1.4.11.4 Interstitial Areas—Measure the areas of load-
A1.4.13 Plannable Gross Area—Measured Elements:
bearing surfaces that are located above or
...