WRC 451 ✓ Most Recent

Part 1: Internal Pressure Design Of Isolated Nozzles In Cylindrical Vessels With d/D Up To And Including 1.00: Report No. 1: Code Rules For Internal Pressure Design Of Isolated Nozzles In Cylindrical Vessels

During the past 30 years, a substantial amount of information has accumulated which indicates that the area-replacement concept, in some applications, is excessively conservative. This excess conservatism increases cost in two ways: (1) the reinforcements contain more metal than needed, and (2) more welding is required. The added welding is probably the more significant; not only in the welding itself but in subsequent inspections (e.g. radiograph, ultrasonic) and repairs of unacceptable flaws. The conservative approach to nozzle design also affects the re-rating of existing vessels. A previous bulletin on this subject, Welding Research Council Bulletin 335, addressed the area of replacement issue for nozzles and branch connections. Subsequent to the publication of WRC 335, paragraph 1-7(b) was added to Section VIII, Division 1 Appendix 1-7, and several additional sources of data on linear elastic stresses at nozzles in cylindrical vessels have become available. The need for better rules for large diameter openings as well as an improved design approach for non-radial nozzles is the basis for this work. This bulletin consists of two reports. The first by E. Rodabaugh is a review of design requirements in existing codes and standards, including selected foreign codes. The design criteria are evaluated by comparison with test data and elastic finite element results. Recommendations to improve the current design rules are made for both radial and non-radial openings. The evaluation includes nozzle geometries with a ratio of nozzle diameter to vessel diameter of 1.0. The second report by Professor Sang of the Nanjing University in China provides experimental data on fully instrumented pressure vessels with both radial and non-radial nozzles subjected to internal pressure. The vessels were pressurized to failure. The strain gage data goes well into the inelastic regime and provides an experimental basis for the validation of elastic-plastic finite element analysis.

Part 2: Internal Pressure Design Of Isolated Nozzles In Cylindrical Vessels With d/D Up To And Including 1.00: Report No. 1: Code Rules For Internal Pressure Design Of Isolated Nozzles In Cylindrical Vessels

During the past 30 years, a substantial amount of information has accumulated which indicates that the area-replacement concept, in some applications, is excessively conservative. This excess conservatism increases cost in two ways: (1) the reinforcements contain more metal than needed, and (2) more welding is required. The added welding is probably the more significant; not only in the welding itself but in subsequent inspections (e.g. radiograph, ultrasonic) and repairs of unacceptable flaws. The conservative approach to nozzle design also affects the re-rating of existing vessels. A previous bulletin on this subject, Welding Research Council Bulletin 335, addressed the area of replacement issue for nozzles and branch connections. Subsequent to the publication of WRC 335, paragraph 1-7(b) was added to Section VIII, Division 1 Appendix 1-7, and several additional sources of data on linear elastic stresses at nozzles in cylindrical vessels have become available. The need for better rules for large diameter openings as well as an improved design approach for non-radial nozzles is the basis for this work. This bulletin consists of two reports. The first by E. Rodabaugh is a review of design requirements in existing codes and standards, including selected foreign codes. The design criteria are evaluated by comparison with test data and elastic finite element results. Recommendations to improve the current design rules are made for both radial and non-radial openings. The evaluation includes nozzle geometries with a ratio of nozzle diameter to vessel diameter of 1.0. The second report by Professor Sang of the Nanjing University in China provides experimental data on fully instrumented pressure vessels with both radial and non-radial nozzles subjected to internal pressure. The vessels were pressurized to failure. The strain gage data goes well into the inelastic regime and provides an experimental basis for the validation of elastic-plastic finite element analysis. See more