As the construction code for new tanks, API 650 sits in the background covering all the aspects of repair and reconstruction of a tank not specifically over-ridden by anything in API 653. API 650 contains detailed construction details for all parts of a tank. It is logically set out and easier to follow than, for example, ASME VIII-I for pressure vessels. Figure 34.1 shows the breakdown. Almost all the API 653 exam questions sourced from API 650 appear in the open-book section of the exam and are straightforward to track down once you find the correct section. Approximately half the code is taken up with 26 annexes at the end; however, only those shown in Figure 34.1 are in the BoK. Several only have one or two clauses of annex included in the BoK; these normally comprise a definition of some sort and make good points for examination questions.