Double-tubesheet heat exchangers: Necessities and challenges Among all types of heat exchangers, shell-and-tube heat exchangers are in huge demand for industrial applications. Among all types of heat exchangers, shell-and-tube heat exchangers are in huge demand for industrial applications. They are suitable for highly corrosive operating fluids and are appropriate for a broad range of pressure and temperature conditions. These heat exchangers are equipped with a single partition between the shell-side and the tube-side fluid that is popularly known as a tubesheet. Leakage can typically occur through the tube-to-tubesheet joint, which is generally the weakest point in heat exchangers. This leakage can contaminate the other side with lower operating pressure, adversely affecting process parameters. These leakages cannot be avoided even after properly designing the tube-to-tubesheet joint by using a strength-welded and light-expanded joint with an appropriate mockup in the fabrication stage.