For the tubular fluorescent lamps T5 and T8 often used for indoor lighting (fig. and fig.) or compact fluorescent lamps with socket 2G11 and external control gear unit (fig.), the lamp maintenance factor LaMF can be determined as the product of lamp lumen maintenance factor LLMF and the lamp survival factor LSF from the corresponding average-value curves.
Lamp Maintenance Factor of a fluorescent lamp
The diagrams are taken from the 2005 publication "Lebensdauerverhalten von Entladungslampen für die Beleuchtung" ("Service life behaviour of discharge lamps for lighting"), published by the Fachverband Elektrische Lampen (formerly Electrical Lamp Specialists’ Association, today Lighting Division) within ZVEI – Zentralverband Elektrotechnik- und Elektronikindustrie e.V. The diagrams are based on a switching rhythm of 11 hours "on" and 1 hour "off".