The second most common type, and almost as prolific as storage vessels, is the heat exchanger. Found in almost every aspect of life, from food service to industrial plants, heat exchangers make modern processing and manufacturing possible. It is widely known that heat, by its very nature, can be a negative aspect to many industrial processes and as such has to be removed or reused to provide for this concern. Thus it is critical that any heat exchanger design have an emphasis on the material chosen to ensure that the vessel can be operated at peak optimization for extended periods. Carbon steel is a common material but usually more stringent alloys are used to ensure longevity and proper functioning.