Fluorescent lamp sizes
Fluorescent tube lamps are typically identified by a code such as FxxTy, where F is for fluorescent, the first number (xx) indicates either the power in watts or length in inches, the T indicates that the shape of the bulb is tubular, and the last number (y) is the diameter in eighths of an inch . Typical diameters for commercial buildings are T5 (5/8″ or 16 mm) and T8 (1″ or 25.4 mm).
