The DALI DT1 Duration Test verifies the battery autonomy of an emergency luminaire by simulating a long mains outage (typically 1 h or 3 h depending on the EN 50172 category); a failure indicates an end-of-life or faulty battery that requires replacement.

The Duration Test is the annual test required by EN 50172. Emergency luminaire categories under EN 50172 mandate a minimum 1 h autonomy (categories 1, 2 and 3), with a nominal autonomy generally of 1 h, going up to 3 h for specific installations. The test must be scheduled outside of occupancy hours (night or weekend). A failure means the battery is at end of life and must be replaced — typical battery life is 4-7 years.

Maintain a small stock of pre-charged replacement batteries on site — a failed duration test makes the affected luminaire non-compliant until repair, with potential insurance impact.