Sizes the number of luminaires needed to hit a target maintained illuminance in a room, using the standard lumen method \u2014 and, on the advanced, checks measured emergency/escape lighting illuminance against EN 1838's minimum and uniformity-ratio requirements.
Standards followed
EN 12464-1 (interior lighting of work places)IES Lighting Handbook (US)EN 1838 (emergency lighting)
What it can do
- Interior room-type presets with standard representative illuminance targets (EN 12464-1 or IES).
- Room Index (K), exact and rounded-up required luminaire count, and achieved illuminance from the rounded count.
- Advanced: exterior/area room types (car parks, building exteriors).
- Advanced: EN 1838 escape-route/anti-panic/high-risk-area minimum illuminance and uniformity-ratio pass/fail check.
Example problem
A 10m × 8m office needs a maintained 500 lux, using luminaires rated 5,000 lm each, with utilization factor 0.6 and maintenance factor 0.8.
- Room area = 10 × 8 = 80 m².
- Room Index K = (L×W) / (Hm×(L+W)) — with a typical mounting height, K ≈ 1.778.
- Exact luminaire count N = (E × Area) / (Flux × UF × MF) = (500 × 80) / (5000 × 0.6 × 0.8) ≈ 22.73.
- Round up to a whole number of luminaires: N = 23.
- Achieved illuminance with 23 luminaires ≈ 506 lux.
23 luminaires required, achieving 506 lux against the 500 lux target.
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