ABSTRACT
Fluorescent lamps are low-intensity gas discharge lamps. Compared with the traditional incandescent lamps, fluorescent lamps exhibit an advantageous performance due to the following factors: these lamps have a luminous efficiency that ranges from 60 to 90l m/W, a color rendering index of above 80 and a life expectancy between 8000 h and 15000 h1. Based on the form of light source used, fluorescent lamps are classified into three types, namely straight tube fluorescent lamps, compact fluorescent lamps, and circular fluorescent lamps. Out of the above-mentioned light sources, straight tube fluorescent lamps and compact fluorescent lamps are largely used in subway stations. A straight tube fluorescent lamp falls into two length categories such as 600 mm and 1200 mm and four diameter categories such as T12, T8, T5, and T4. It also acquires many forms such as U-type, spiral-type, H-type, and so on (Figure 1). The advantages of a compact fluorescent lamp are as follows: small size, high luminous efficiency, and long life. It is suitable for downlight lighting. The disadvantage of fluorescent lamps is mercury population. Mercury
disadvantages such as long starting time, not being frequently opened, and large fading of light. These disadvantages limit their scope of application in subway stations and only those with higher space stations will choose to use metal halide lamps.
