The subjects in this chapter could be deemed good design practice. Most but not all process and power plant heat exchanger specifications contain requirements related to the topics covered. When requirements are not specified—a common occurrence in commercial units—manufacturers should make selections in general agreement with the limitations found in this chapter. Some causes of trouble include too high a water velocity (pitting), geometry (won't fit in available space), use of too much water (existing piping cannot carry the quantity needed), high air velocity (blowing condensate off coil), and stacking (assuring seals do not leak) to name a few. Even then, omission of requirements from specifications can lead to disputes. A typical disagreement between might be, The unit delivered has an 80 dB(A) noise level while the plant standard is 75 dB(A). How can the rater know this or any other limitation if it is not in the specifications?
This chapter is intended as a reference to avoid trouble, for buyers to make certain that they are purchasing what they want, for sales personnel to assist in avoiding trouble, and for plant engineers to supply as complete a set of requirements as possible. Most of the topics touched on can be and have been the cause of trouble.