Lamp ignition under specified conditions, the lumen maintenance is the light flux in a specific time during the life of the lamp to the initial luminous flux of the lamp ratio, usually expressed as a percentage. With the increase of the ignition time, the light flux will reduce. Effective lifetime is defined based on lumen maintenance. When the lumen maintenance is less than 50%, it can be regarded as the life of the lamp has been reached end.
GB Requirements: 2000H not less than 78%.
The advanced level abroad: 2000H not less than 90%.
American Energy Star: not less than 80% when reach 40% rated life.
Domestic level: companies focused on quality and the use protective film technology basicly all can reach GB.