kestus, mille möödumisel vastavalt tootja või vastutava tarnija deklaratsioonile nähakse leedvalgusallikate hulga kohta ette valgusvoo vähimalt nõutav säilivus ning ülimalt lubatav tõrkesuhe Fy, length of time during which a population of LED light sources provides at least the claim for maintained luminous flux percentage and at most the claim for failure fraction percentage Fy, as declared by the manufacturer or responsible vendor