Recommended functional units
Functional units represent the quantification of the use of the building. They are client specific as they reflect how the building will be used. The exact definition of commonly used functional units should be agreed with the client on each project.
The industry standard definition for net internal area (NIA) is available in the RICS Code of Measuring Practice. It is commonly used to define net lettable floor area and widely used for offices.
Note: NIA is not the same as ‘Usable floor area’ defined in Section 4.
More than 1 functional unit is given against some building types, either because:
- more than 1 functional unit is applicable to the building type, e.g. housing is normally described by both occupancy (Nr of persons) and number of bedrooms; or
- there are alternative functional units depending on the nature of the individual facility, e.g. a communal residential facility may either provide individual bedrooms or communal sleeping areas.
Functional units
Transport
| Coach and bus stations | Nr of vehicle spaces |
| Car parks | Nr of vehicle spaces |
| Garages | Nr of vehicle spaces |
Industrial
| Livestock buildings - farms (pig pens, milking parlours, etc.) | Nr animals |
| Factories | m² net internal area |
| Warehouses/stores | m² net internal area |
Administrative, commercial, protective
| Law courts | Nr of courtrooms |
| Offices |
m² net internal area |
| Nr of persons | |
| Retail warehouses | m² retail area |
| Shopping centres | m² retail area |
| Department stores | m² retail area |
| Shops | m² retail area |
| Fire stations | Nr of vehicle spaces |
| Ambulance stations | Nr of vehicle spaces |
| Prisons |
Nr of bedspaces |
Health and welfare
| Hospitals | Nr of bedspaces |
| Nr theatres/treatment rooms | |
| Nr practitioners’ suites | |
| Pharmacies, dispensaries | Nr population served |
| Outpatients/casualty unit | Nr population served |
| Health centres, clinics, group practice surgeries |
Nr practitioners’ suites |
| Nr population served | |
| Dentists surgeries |
Nr practitioners’ suites |
| Nr population served | |
| Homes |
Nr of persons |
| Nr bedrooms | |
| Day centres | Nr of persons |
| Veterinary hospitals | Nr of animals |
| Animal clinics | Nr of practitioners’ suites |
| Animal rearing and living facilities | Nr of animals |
Recreational facilities
| Canteens, refectories | Nr of places |
| Meals per hour | |
| Nr population served | |
| Restaurants | Nr of places |
| Public houses, licensed premises | m² retail area |
| Dance halls, ballrooms, discothèques | Nr of places |
| Concert halls | Nr of persons |
| Theatres | Nr of places |
| Cinemas |
Nr of places |
| Nr of screens | |
| Community centres, general purpose halls, etc. | Nr of persons |
| Swimming pools |
Nr of persons |
| Nr population served | |
| Boat houses (private and recreational) | Nr of vehicle spaces |
| Sports centres/recreational centres |
Nr of persons |
| Nr of sports courts | |
| Squash courts, tennis courts, etc. | Nr of sports courts |
| Stadia |
Nr of places |
| Nr of persons | |
| Sports pavilions, club houses and changing rooms | Nr of persons |
Religious
| Churches, chapels, temples, mosques, etc. | Nr of persons |
Education, scientific, information
| Schools | Nr of places |
| Universities, colleges, etc. | Nr of places |
| Libraries | Thousand volumes |
| Population served | |
| Nr of places | |
| Record offices, archives, patent offices | Thousand volumes/records |
Residential
| Housing (houses and flats) | Nr of persons |
| Nr of bedrooms | |
| Gross internal floor area of the units | |
| Hotels, motels, guesthouses | Nr of bedrooms |
| Dormitories |
Nr of bedrooms |
| Nr of persons | |
| Nurses residence, student’s residence, halls of residence, etc. |
Nr of bedrooms |
| Nr of persons | |
| Barracks, mess accommodation, section houses, etc. |
Nr of bedrooms |
| Nr of persons | |
| Youth hostels |
Nr of bedrooms |
| Nr of persons | |
| Short stay hostels for homeless, etc. |
Nr of bedrooms |
| Nr of persons |
Common facilities, other facilities
| Conference centres | Nr of places |
| Kitchens |
Meals per hour |
| Population served | |
| Public conveniences, toilet blocks, utility blocks | Nr of places |
| Boiler houses | kW |