Assessment of the circadian stimulus potential of an integrative lighting system in an office area

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Summary

This field study at a Swedish office building evaluated an integrative lighting system's ability to support circadian health by measuring equivalent melanopic lux (EML) through photometric measurements, ALFA simulations, and wrist-worn sensors. Results indicate that the system can meaningfully modulate EML—particularly in daylight-poor zones—and that most occupants reported increased alertness with higher CCT·lux values, though simulated EML values exceeded measured ones except under electric-only lighting conditions.

Key Findings

Alertness increased in most participants with higher values of the combined metric CCT·lux (correlated color temperature × illuminance) as recorded by wrist-worn devices.
ALFA circadian lighting simulations consistently yielded higher EML values than on-site measurements; the closest agreement between simulated and measured EML occurred under electric-only lighting conditions.
The integrative lighting system complied with EN 15193 energy benchmarks for both existing and direct lighting systems despite being designed primarily for circadian health rather than energy efficiency.
Most participants expressed positive attitudes toward the lighting system in semi-structured interviews.
The system demonstrated capacity to steer EML especially in areas with limited daylight access, indicating practical benefit for interior office zones.

Categories

Workplace Performance: Field study evaluating alertness and circadian stimulus potential of an integrative lighting system in an office environment.

Sleep & Circadian Health: Study measures equivalent melanopic lux (EML) and circadian entrainment potential of office lighting using simulation and wrist-worn sensor data.

The Science of Light: Applies melanopic EDI (EML) metrics, ipRGC-based non-visual light effects, and ALFA circadian simulation tools to evaluate a real-world lighting installation.