Fluorescent lamps: High luminous efficacy and long life
Did you know that more than 70 percent of indoor lighting is realised with fluorescent lamps? This is because of the economies they achieve with a combination of high luminous efficacy and long life. The average life of fluorescent lamps is between 5,000 and 45,000 hours, depending on operating mode and type; that of an incandescent lamp is just 1,000 hours.
Fluorescent lamps are low-pressure discharge lamps. When electric current flows through the lamp bulb (=discharge tube), mercury atoms inside it are excited and produce UV radiation. This is then converted into visible light by the fluorescent coating on the lamp bulb. The composition of the coating determines light colour and colour rendering.
Fluorescent lamps require ballasts
Fluorescent lamps require ballasts to regulate the gas discharge and ensure comfortable and efficient operation. The best energy efficiency ratings are achieved with electronic ballasts (EBs). They are also available as dimmable models.
Fluorescent lamps: 16 and 26 millimetre diameter
A distinction needs to be made between lamps with 26 and 16 mm diameter tubes. 16 mm lamps are designed for EB operation only. They are available in two type series: "high luminous efficacy" for maximum efficiency and "high luminous flux" for optimum lamp power.
Fluorescent lamps are available in all three light colours: warm white, neutral white, daylight white. Colour rendering is good (Ra ≥ 80), in the case of "de luxe" lamps very good (Ra ≥ 90). With a luminous efficacy of 90 lm/W through to more than 100 lm/W, light generation is very economical. Lamp life is also very good; peak performers burn for more than 20,000 hours.
Alternatives: 7 and 38 millimetre diameter
Fluorescent lamps with a 26 or 16 mm tube diameter are the linear fluorescent lamps in most widespread use. But there are others: 7 mm diameter lamps for display, furniture and picture lights and 38 mm diameter specialists for work premises with potentially explosive atmospheres or for use in low temperatures, e.g. in outdoor lighting or in cold storage facilities.
