Under DIN 277:2021-08, technical area (TF) and circulation area (VF) are the two parts of the net room area that do not serve the building’s intended purpose: the TF houses the building services, the VF opens up the rooms – access, circulation, escape. Together with the usable area they make up the NRF.
In short
- TF: boiler, ventilation, electrical and lift machine rooms – rooms where plant stands.
- VF: corridors, stairwells, lifts, entrance halls, ramps – areas by which one reaches the rooms.
- An aisle within an office is not VF: it belongs to the room’s usable area.
Definition under DIN 277:2021-08
The technical area – until 2016 Funktionsfläche (FF) – is the floor area of the rooms serving the building’s services installations: waste water and water supply, heating, ventilation, electrical and telecommunications engineering, lift machinery. The circulation area is the floor area of the rooms and areas serving access to the rooms, circulation within the building and leaving it in an emergency: corridors, stairwells, lift shafts on every level, entrance halls, ramps. Both are measured like any net room area in clear dimensions and allocated to category R or S – an external access balcony is circulation area in category S.
Distinction
| Area type | Serves | Examples | Counts towards NRF |
|---|---|---|---|
| NUF | the intended purpose | living room, office, storeroom, classroom | yes |
| TF | the building services installations | boiler room, ventilation plant room, service entry room | yes |
| VF | access, circulation, escape | corridor, stairwell, lift, entrance hall | yes |
In practice
The share of TF and VF in the net room area is an indicator of a building’s area efficiency – the smaller, the more area serves the purpose. In building cleaning, circulation areas have their own intervals and productivity rates, in CAFM systems their own room types; in the housing industry, stairwells and corridors are common areas that never count towards living area but stand in the room book as circulation area.
The floor plan shows the room, not its area type. A corridor is recognisable as such, a room with a boiler only if labelled or the plant is drawn in. Unlabelled shafts, lift pits and landings are the typical allocation cases someone has to decide.
Normraum relevance
Corridors, stairwells and plant rooms stand in the Normraum room book as separate lines with area under DIN 277, confidence and source reference – they are not silently added to the usable area. The allocation to TF or VF follows the use per room and remains a professional sign-off. What the floor plan does not show unambiguously – unlabelled shafts, lift pits – the planner or the on-site survey clarifies.