TEMA standards provide for two classes of shell and tube exchanger qualities. Class C is the less stringent and is typically used in onshore applications and where the temperature is above ~20°F. Class R is normally used offshore and in cold temperature service. Table 3-2 shows the most important differences between a Class R and a Class C TEMA exchanger.
Table 3-3 is a tube materials selection chart (the common tube materials to use for different kinds of services). Standard tube lengths are either 20 ft or 40 ft.
