Norway — TEK17 §13-7
Legal status
Mandatory. TEK17 (Byggteknisk forskrift) is the regulation under the Norwegian Planning and Building Act. Daylight is covered by §13-7 Lys. The regulation states a functional requirement; the numeric criteria below are the pre-accepted performance levels (preaksepterte ytelser) in the official guidance (veiledning) from the Norwegian Building Authority (DiBK).
Requirement
| Item | Value |
|---|---|
| Metric | Average daylight factor (DF) per room |
| Threshold | Average DF ≥ 2.0 % in the room |
| Simplified alternative | Glazing area Ag ≥ 0.07 · ABRA / LT (0.10 · ABRA for leisure housing/fritidsbolig), where ABRA is the room's usable floor area and LT the glass's light transmittance |
| Assessment level | Per room, for rooms for lasting stay (rom for varig opphold) |
| Calculation method | Follows NS-EN 17037 |
Older guidance referred to a light-opening / NS 3940 area calculation. NS 3940 is the Norwegian standard for measuring areas and volumes of buildings — it is not a daylight method. The daylight factor calculation itself follows NS-EN 17037.
Calculation setup
| Parameter | Value | Notes |
|---|---|---|
| Reference plane height | 0.85 m above floor | From NS-EN 17037 |
| Grid spacing | p = 0.5 · 5log₁₀(d) m | NS-EN 17037 formula; d = longest room dimension when the length/width ratio is 0.5–2, otherwise the shortest |
| Wall offset (excluded border) | 0.5 m | NS-EN 17037 |
| Sky model | CIE standard overcast sky |
Reflectances are not stated in TEK17/veiledning; see Reflectance for the values LUX uses.
How LUX handles it
Status: ✅ Supported in LUX Live v0.3.0.
LUX has a Norway mode: it reports the average DF per room and flags each room green (≥ 2.0 %) or red. Average DF per room is already part of the LUX output, so this is a reporting layer on the existing computation.
Sources
- TEK17 §13-7 Lys — veiledning (guidance, incl. pre-accepted performance levels) — Direktoratet for byggkvalitet (DiBK) (free)
- TEK17 §13-7 Lys — regulation text — Direktoratet for byggkvalitet (DiBK) (free)
- NS-EN 17037:2019 — Dagslys i bygninger — Standard Norge (paid standard)
- NS 3940:2023 — Areal- og volumberegninger av bygninger — Standard Norge (paid standard; area/volume method, not daylight)