Under DIN 277:2021-08 the usable area (NUF) is the part of the net room area serving the building’s intended purpose – living, working, storing, teaching, healing. The standard distinguishes seven use categories, NUF 1 to NUF 7. What serves not the purpose but operation or access is technical or circulation area.
In short
- The NUF is the “productive” area of a building; its share of the net room area is an efficiency indicator.
- Seven use categories classify each room by its main purpose; sanitary and storage rooms fall under NUF 7.
- The use category is not in the floor plan – it is an allocation someone makes and documents.
Definition under DIN 277:2021-08
Each room is allocated as a whole to the use category matching its predominant purpose. The 2021 edition took the seven use categories over unchanged from 2016 and extended NUF 7 by rooms whose intended purpose is not yet determined. Until 2016 the quantity was called Nutzfläche (NF).
| Use category | Name | Examples |
|---|---|---|
| NUF 1 | Living and recreation | living rooms, bedrooms, common rooms and break rooms |
| NUF 2 | Office work | offices, meeting rooms, counter halls |
| NUF 3 | Production, manual and machine work, research and development | production halls, workshops, laboratories, kitchens |
| NUF 4 | Storage, distribution and sales | storerooms, archives, sales rooms |
| NUF 5 | Education, teaching and culture | classrooms, libraries, exhibition and sports rooms |
| NUF 6 | Healing and care | examination, treatment and care rooms |
| NUF 7 | Other uses | sanitary rooms, cloakrooms, storage rooms, rooms without a determined intended purpose |
Distinction
| Area type | Serves | Examples |
|---|---|---|
| NUF | the intended purpose of the building | living room, office, storeroom, classroom |
| TF | the building services installations | boiler room, ventilation plant room, electrical room |
| VF | access, circulation, escape | corridor, stairwell, lift, entrance hall |
All three together form the net room area. An aisle within a room – in an open-plan office, say – is not circulation area but part of that room’s usable area.
In practice
The NUF total per floor and building is what space management, room schedule comparison and indicators work with: euros per square metre NUF, NUF per workplace, NUF share of the NRF. In existing buildings the use category is often no longer the planned one – the storeroom became an office, the laundry room a storage room. Anyone building a room book must therefore determine the use category per room and document the status; CAFM systems usually expect a room type for this that maps to a NUF class.
The floor plan supplies the geometry and often a room label; whether the label still holds is for the portfolio owner to decide.
Normraum relevance
Normraum lists every room in the room book with use and area under DIN 277; the use category is checked per room and set before export, so NUF totals per floor and building can be summed from the room book. Intended purpose, change of use and borderline cases under NUF 7 remain a professional decision; the check log records which allocation came from where.