scope:

This Code applies to all horizontal and vertical heaters except those with partial pass full-length drain cooling zones. The heater design is based on a specific operating condition that includes flow, temperature, and pressure. This specific condition constitutes the design point that is found on the manufacturer's feedwater heater specification sheet.

Generally, it is not possible to conduct the test at the exact design point. Therefore, it is necessary to predict the heater performance by adjusting the design parameters for the actual test conditions. Methods of calculating the predicted heater performance are presented in this Code. These predicted values shall then be compared to corresponding measured test values.

Horizontal heaters with partial pass submerged drain cooling zones and vertical channel-up heaters with partial pass drain cooling zones are not applicable to this Code. In those designs, only a portion of the feedwater passes through the drain cooling zones, therefore there are two flow streams with different temperature profiles.

Duplex heaters are applicable as long as the feedwater temperatures, including the temperature between stages, are measurable, and the shell sides are isolated from each other and verified to be at different stage pressures.

This Code is applicable for multitube pass heaters of single zone design. Multizone partial pass heaters cannot be tested under this Code, unless the entire first pass is contained in a single zone. This Code also does not apply to header type heaters.