MEASUREMENT OF BUILDING AREAS
This method has been adopted for use by N.P.W.C. members, the Australian Institute of Quantity Surveyors and the Royal Australian Institute of Architects. It should
be noted that local authorities may adopt other methods for the likes of plot ratio calculations and others.
GROSS FLOOR AREA (G.F.A.)
The sum of the Fully Enclosed Covered Area and Unenclosed Covered Area as defined.
Unit of Measurement : Square Metres (sqm)
FULLY ENCLOSED COVERED AREA (F.E.C.A.)
The sum of all such areas at all building floor levels, including basements (except unexcavated portions), floored roof spaces and attics, garages, penthouses,
enclosed porches and attached enclosed covered ways alongside buildings, equipment rooms, lift shafts, vertical ducts, staircases and any other fully enclosed
spaces and usable areas of the building, computed by measuring from the normal inside face of exterior walls but ignoring any projections such as plinths,
columns, piers, and the like which project from the normal inside face of exterior walls. It shall not include open courts, light wells, connecting or isolated covered
ways and net open areas of upper portions of rooms, lobbies, halls, interstitial spaces and the like, which extend through the storey being computed.
Unit of Measurement : Square Metres (sqm)
UNENCLOSED COVERED AREA (U.C.A.)
The sum of all such areas at all building floor levels, including roofed balconies, open verandahs, porches and porticos, attached open covered ways alongside
buildings, undercrofts and usable space under buildings, unenclosed access galleries (including ground floor) and any other trafficable covered areas of the
building which are not totally enclosed by full height walls, computed by measuring the area between the enclosing walls or balustrade (i.e. from the inside face
of the U.C.A. excluding the wall or balustrade thickness). When the covering element (i.e. roof or upper floor) is supported by columns, is cantilevered or is
suspended, or any combination of these, the measurements shall be taken to the edge of the paving or to the edge of the cover, whichever is the lesser. U.C.A.
shall not include eaves overhangs, sun shading, awnings and the like where these do not relate to clearly defined trafficable covered areas, nor shall it include
connecting or isolated covered ways.
Unit of Measurement : Square Metres (sqm)
BUILDING AREA (B.A.)
The total enclosed and unenclosed area of the building at all building floor levels measured between the normal outside face of any enclosing walls, balustrades
and supports.
Unit of Measurement : Square Metres (sqm)
USABLE FLOOR AREA (U.F.A.)
The sum of the floor areas measured at floor level from the general inside face of walls of all interior spaces related to the primary function of the building. This will
normally be computed by calculating the Fully Enclosed Covered Area (F.E.C.A.) and deducting all of the following areas supplementary to the primary function
of the building :
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DEDUCTIONS FROM U.F.A. (a)
Common Use Areas :
All floored areas in the building for circulation and standard facilities provided for the common use of occupiers, tenants and/or the public such as lobbies
and foyers to entrances, lifts, stairways, landings and fire escapes, verandahs and balconies, corridors and passages, toilet and rest room areas, cloak
and locker areas, cleaner’s rooms including stores and cupboards, tea making and similar amenities areas.
(b)
Service Areas :
areas set aside for building plant supplying services and facilities common to the building for the use of occupants, tenants and/or public, such as
All
mechanical plant and equipment rooms, electrical equipment and switchrooms, tank rooms, lift motor rooms, meter cupboards, telecommunication
switchrooms, refuse collection areas, loading bays and all car parks including access ways thereto.
(c)
Non-Habitable Areas :
non-habitable building space such as that occupied by internal columns and other structural supports, internal walls and permanent partitions, lift shafts,
All
service ducts and the like.
Unit of Measurement : Square Metres (sqm)
TREATED AREA (T.A.)
The sum of all areas at all building levels to which a particular engineering service is provided. The area is computed by measuring from the normal inside face
of exterior walls, but ignoring any projections such as plinths, columns, piers and the like which project from the normal inside face of exterior walls, to the centre
line of internal walls, as applicable, which enclose the area treated.
Notes :
(i)
A Treated Area may need to by computed separately for each engineering service.
(ii)
The Treated Area for such services as Space Heating, Ventilation, Evaporative Cooling and Air-Conditioning should include all areas to which treated air
is supplied.
(iii)
The Treated Areas for Fire Protection comprises the sum of protected floor space, the area of protected ceiling spaces and the area of protected underfloor spaces.
Unit of Measurement : Square Metres (sqm)
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Rawlinsons Construction Cost Guide 2022, edited by Rawlinsons Quantity Surveyors, Rawlinsons Publishing, 2022. ProQuest Ebook Central,
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Rawlinsons 2022
MEASUREMENT OF BUILDING AREAS
NET LETTABLE AREA, OFFICE BUILDINGS (N.L.A.)
The sum of all lettable areas within a commercial type office building, measured from the internal finished surfaces of permanent walls and from the internal
finished surfaces of dominant portions of the permanent outer building walls, and including the area occupied by structural columns and engaged perimeter
columns, all in accordance with the Method for the Measurement for Lettable Areas issued by the Property Council of Australia.
DEDUCTIONS FROM N.L.A. (a)
All stairs, toilets, cleaners cupboards, lift shafts, escalators and tea rooms where provided as standard facilities in the building.
(b)
Lobbies between lifts facing other lifts serving the same floor.
(c)
Areas set aside as public space or thoroughfares and not used exclusively by occupiers of the building.
(Note : excludes any additional common areas resulting from sub-division of a whole floor to accommodate more than one tenant).
(d)
Areas set aside as plant and lift motor rooms or for the provision of facilities or services to the building and not for the exclusive use of an occupier or
occupiers of the building.
(e)
Areas set aside for use by service vehicles and for delivery of goods and access ways thereto.
(f)
Areas set aside for car parking and access ways thereto.
(g)
Areas where clear height is less than 1.50 metres.
Unit of Measurement : Square Metres (sqm)
ASSOCIATED DEFINITIONS
STOREYS :
The
number of storeys in a building is the number of main floors above ground level including the ground floor but excluding penthouses or machine or plant
rooms above the main roof level. Basements below ground level should be stated separately (e.g. 2B + 12 storeys).
BUILDING HEIGHT :
The distance measured between the main ground floor level and the upper limit of the structure of the building including parapet walls but excluding guard
rails and the like.
INTERSTITIAL SPACE :
The intervening space between floors providing occasional access for the installation and maintenance of building, engineering and other equipment.
WALL/FLOOR AREA RATIO :
measure of plan efficiency, computed by dividing the face area of the external surfaces of the building* by the Fully Enclosed Covered Area (F.E.C.A.) and
A
expressing the result as a ratio to 1.
* Excludes area of gable walls, parapet walls and walls below lowest finished floor level.
P.O.P. RATIO :
measure of plan compactness, computed by relating the perimeter of a building at a typical floor level to that of a circle enclosing the same area and
A
expressing the result as a percentage.
The formula for P.O.P. ratio is :
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P.O.P. = 2 πΑ
P
x 100 where
A = the Fully Enclosed Covered Area (F.E.C.A.) of a typical floor level.
P = the perimeter enclosing that area, measured internally.
(N.B. : The P.O.P. Ratio for a circle = 100%
The P.O.P. Ratio for a square = 89%)
AREA EFFICIENCY :
measure of design efficiency, computed by dividing the Usable Floor Area* (U.F.A.) by the Gross Floor Area (G.F.A.) and expressing the result as a
A
percentage.
* Net Lettable Area (N.L.A.) may be substituted for Usable Floor Area (U.F.A.) in commercial type premises.
AREA PERCENTAGE :
The percentage that the Fully Enclosed Covered Area (F.E.C.A.) and the Unenclosed Covered Area (U.C.A.) each bear to the Gross Floor Area (G.F.A.).
NOTE : In measuring building areas from drawings, figured dimensions should be used in preference to scaled dimensions.
Edition 30
306
Rawlinsons Construction Cost Guide 2022, edited by Rawlinsons Quantity Surveyors, Rawlinsons Publishing, 2022. ProQuest Ebook Central,
http://ebookcentral.proquest.com/lib/tafenswlib/detail.action?docID=6881770.
Created from tafenswlib on 2023-03-15 04:25:18.
Rawlinsons 2022