The following table shows how eTool defines areas within the software:
| Australian Construction Handbook Definitions (Rawlinsons) | Simplified eTool Notes | UK Equivalent | ||
| Term | Abbreviation | Description | ||
| Gross Floor Area | GFA | The sum of the Fully Enclosed Covered Area and Unenclosed Covered Area as defined. | No Change | Gross External Area |
| Fully Enclosed Covered Area | FECA | 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, 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 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. | As for Rawlinsons but projections are generally included in the measurement and measurement may be from the outside, centre or inside of external walls depending on the models and plans used to develop the inventory | Gross Internal Area |
| Unenclosed Covered Area | UCA | The sum of all such area at all building floor levels, including roofed balconies, open verandahs, porches, porticos, attached open covered ways alongside buildings, undercrofts and useable 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 my measuring the area between the enclosing walls or balustrade (i.e. from the inside face of the UCA. excluding the wall or balustrade thickness). When measurements shall be taken to the edge of the paving or to the edge of the cover, whichever is the lesser. UCA shall not include eves, overhangs, sun shading, awnings and the like where these do not relate to clearly defined trafficable covered areas, nor shall if include connecting or isolated covered ways. | As for Rawlinsons but area of balustrades is generally included and measurement may be from the outside, centre or inside of external walls depending on the models and plans used to develop the inventory | |
| Building Area | BA | 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. | No Change | |
| Usable Floor Area | UFA | The sum of the floor areas measured at floor level from the general inside face of walls and all interior spaces related to the primary function of the building. This will normally be computed by calculating the Fully Enclosed Covered Floor Area (FECA) and deducting all the following areas supplementary to the primary building function: – Common Use Areas: All floored areas in the building for the circulation and standard facilities provided for the common use of occupiers, tenants and / or the public such as lobbies and foyers to entrances, lifts, landings, and fire escapes, verandahs and balconies, corridors and passages, toilet and rest room areas, cloak and locker areas, cleaners rooms including stores and cupboards, tea making and similar amenities. – Service Areas: All areas set aside for the building plant supplying services and facilities common to the building for the use of occupants, tenants, and / or the public such as mechanical plant and equipment rooms, electrical equipment and switch rooms, tank rooms, lift motor rooms, meter cupboards, telecommunication switch rooms, refuse collection areas, loading bays and all car parks including access ways thereto. – Non Habitable Areas: All non-habitable building space such as that occupied by internal columns and other structural supports, internal walls and permanent partitions, lift shafts, service ducts and the like. |
As for Rawlinsons but will generally include non-habitable areas. | Net Internal Area |
| Treated Area | TA | The sum of all areas at all building levels to which a particular engineering services is provided. The area is computed by measuring from the normal inside f ace 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 center line of internal walls, as applicable, which enclose the area treated. NOTE: Treated area may need to be calculated separately for each engineering service. The treated area to such services as space heating, ventilation, evaporative cooling and air-conditioning should include all areas to which the treated air is supplied. The treated areas for fire protection comprises the sum of protected floor space, the area of protected ceiling spaces and the area of protected under floor spaces. | As for Rawlinsons, generally only applied to “Conditioned Area” | |
| Net Lettable Area, Office Buildings | NLA | 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 Area issued by the Property Council of Australia. Deductions from NLA: – All stairs, toilets, cleaners cupboards, lift shafts, escalators, and tea rooms where provided as standard facilities in the building. – Lobbies between lifts facing other lifts serving the same floor – 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 subdivision of a whole floor to accommodate more than one tenant) – Areas set aside as plant and lift motor rooms of for the provision of facilities or services to the building and not for the exclusive use of an occupier or occupiers of the building – Areas set aside for use by service vehicles and for delivery of goods and access ways thereto – Areas set aside for car parking and access thereto – Areas where clear height is less than 1.5m |
As for Rawlinsons but will generally include non-habitable areas. | |
How Different Functions Deal with Floor Areas
Different functions will give you different input fields to complete. For example, a Residential function will not have input fields for ‘Net Lettable Area’ or ‘Annual Operating Hours’ because those are specifically for commercial buildings. Different functions will also have different floor area inputs depending on what’s relevant for that function. Most of our building related functions will have ‘Gross Floor Areas’ (GFA), ‘Usable Floor Areas’ (UFA), ‘Fully Enclosed Covered Areas’ (FECA) & ‘Unenclosed Covered Areas’ (UCA) while infrastructure type functions will have inputs that are more relevant for the respective functions. Below are some examples of the typical functions in eTool and our recommended useage. Open air carparks and pavement areas do not fall under our definitions for GFA however it can be useful to have a dedicated function for those areas that won’t affect the total GFA. For example if you want to use a lighting template with eTool default operational energy calculations for the open air carpark areas – you could assign specific lighting run-times and lux levels for these areas with it’s own dedicated function characteristics that won’t affect the total GFA.
