ANSI C78.79:2014

This standard describes a system of nomenclature that provides designations for envelope shapes used for all electric lamps. This system is shown in customary (inch-based) units and SI (metric-based) units. These envelope shapes are intended to be used with ANSI standardized base and holder systems. These general shapes are not associated with specific base and holder systems; they may be used with one or more of these systems. The nomenclature system is intended for application with LED lamps and glass bulbs that originate both as parts and as stock. As a part, a bulb is assembled directly into finished lamps without major alterations. As stock, a bulb may be reworked or altered during lamp assembly, while maintaining its basic identifying characteristics.