#### 6.3.3 Tubeplate thickness

The tubeplate thickness is found by application of BS5500, the calculation being shown in Fig 3.49, using the suggested working form for U-tube tubesheet design, page 3/96.

The values of the coefficients, which are given in Table 3.9 of BS5500, are also shown in graphical form to demonstrate how they are obtained during the course of the calculation. If a single bank of HP feedwater heaters is considered in place of the double bank, for the same velocity of water in the tubes, the flow area would have to be doubled.

If it is assumed the area required to accommodate the doubled number of tubes is twice that previously needed, then the tube bundle diameter will be V2 times the original diameter, with a consequent increase of tubeplate thickness to 550 *mm*.