Seeking help regarding Japanese standard flanges
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How are Grades I, II, and III classified in the JIS standard?
The type of flange to be used, whether it is Class I, II, or III, can be found in the table below. Then, the maximum required pressure can be found using Table 1. I feel that flanges are divided into three categories based on size and type.
Thank you. I have another question: the notation used in the example does not indicate whether it belongs to category I, II, or III. How can I determine which category it is? The picture is downstairs.
Based on the flange type, size, material, and pressure rating, refer to Table 2 to determine whether the flange belongs to Class I, II, or III; then use Table 1 to find the maximum allowable working pressure. This type is only used to determine the maximum allowable operating pressure.
This table is a selection guide based on material, pressure, and temperature; since flange types are not taken into account, no selection can be made. The actual selection guide for different types of flanges is Table 12, which is derived from this table for specific flange types. Therefore, use flanges first according to Table 12.
Tables 11 and 12 must be used together in order to determine the flange type, as well as the maximum operating pressure and temperature combinations for the lower flange material