Shell & Tube heat exchangers are tubular heat exchangers in which tubes are installed inside of a pipe shell. One fluid flows inside of the shell while the other fluid flows in the annulus space between the outside of the tubes and the inside of the shell. These heat exchangers can be fabricated from many materials ranging from carbon steel or stainless steel to nickel alloys or titanium. These shell & tube heat exchangers can have design temperatures over 1,000° F and pressures to 10,000 psig.