Jacketed piping provides the most uniform application of heat to the process and maintains the most uniform process temperatures. Jacketed piping is used most frequently with processes that have a narrow temperature range, require very uniform temperature maintenance, and/or must have maximum heat input for melt-out or heat exchanger service. Jacketed piping features a core pipe which is completely surrounded by a jacket pipe. Process flows through the core pipe, while a heating medium (or cooling medium) flows in the annular space between the core and jacket pipes.