Section 12 Boiler tubes subject to external pressure
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Naval Ships, January 2023 - Volume 2 Machinery and Engineering Systems - Part 8 Pressure Plant - Chapter 1 Steam Raising Plant and Associated Pressure Vessels - Section 12 Boiler tubes subject to external pressure

Section 12 Boiler tubes subject to external pressure

Parent topic: Chapter 1 Steam Raising Plant and Associated Pressure Vessels

12.1 Tubes

12.1.1 The thickness of tubes is to be in accordance with Table 1.12.1 Thickness of plain tubes under external pressure for the appropriate outside diameter and design pressure.

Table 1.12.1 Thickness of plain tubes under external pressure

Design pressure, in MPa Thickness,
in mm
Outside diameter, in mm
38 44,5 51 57 63.5 70 76 82.5 89 95 102
— — — — — — — — — 2,69 2,52 5,89
— — — — — — — 2,62 2,41 2,28 2,14 5,38
— — — — — — 24,1 22,1 20,7 19,3 17,9 4,88
— — — 2,76 2,48 2,28 2,07 1,93 1,79 1,66 1,59 4,47
— 2,93 2,55 2,28 2,07 1,89 1,73 1,59 1,48 1,37 1,27 4,06
2,66 2,28 2,07 1,79 1,59 1,48 1,31 1,24 1,14 1,03 0,96 3,66
2,03 1,69 1,48 1,31 1,21 1,10 0,96 0,89 0,82 0,76 0,69 3,25
1,48 1,24 1,07 0,96 0,86 0,76 — — — — — 2,95

12.1.2 Tubes may be welded at both ends, welded at the inlet end and expanded at the outlet end, or expanded at both ends. In addition to expanding, tubes may be bell mouthed or beaded at the inlet end. Where tubes are welded, the weld detail is to be as shown in Figure 1.9.4 Detail of weld for tube and the tubes are to be expanded into the tube plates in addition to welding, except as permitted by Vol 2, Pt 8, Ch 1, 12.1 Tubes 12.1.3.

12.1.3 For tubes of thickness greater than 6,0 mm, expanding in addition to welding is not required if a recessed weld of depth not less than the tube thickness is provided.

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