When calculating the 6% allowance using the area method for handholes, etc., is it necessary to add a circle?

In this case, whether a reinforcement ring is needed depends on the specific design standards and safety requirements. Generally, if the reinforcement area margin is below a certain percentage (such as 10%), it may be necessary to increase the reinforcement rings in order to enhance the structural integrity and safety of the container. However, a 6% margin does sound quite low, indicating that the strength of the reinforced structure is close to, but possibly below, the minimum value required by the design. In the situation you mentioned, for a vertical vessel with a diameter of 1.6 meters and an operating pressure of 0.45/FV, the margin for reinforcement area at the manhole, as calculated under vacuum conditions, is 6%; this may indicate that reinforcement measures such as reinforcement rings are necessary to ensure the safety and reliability of the vessel under the most adverse conditions. Adding reinforcement rings can effectively improve the strength of the reinforced area, reduce stress concentration caused by openings, and enhance the overall structural stability of the container. However, the final decision should be based on the applicable design codes and standards (such as the ASME Pressure Vessel Code), as well as a detailed analysis of the vessel’s operating conditions, material properties, and safety factors. It is recommended to consult qualified pressure vessel design engineers or use professional design software for detailed calculations to ensure compliance with all relevant safety and design requirements. .

In principle, as long as it can be calculated, there is no need to add reinforcing rings; the requirement for a six-in-one design is that the margin must not be less than 15%