In this case, should the value of E1 be 0.85 or 1?
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This post was last edited by Akihi on 2026-7-9 08:50. When calculating flange openings for reinforcement according to ASME standards, what value should be used for E1 in the formula for the reinforcement area provided by the head?
It seems the original poster didn’t finish their question😆 If we’re talking about the calculations for reinforcing openings according to ASME standards, it’s necessary to first determine specific parameters such as the location of the openings, the dimensions of the connections, the design pressure and temperature of the container, as well as its material. Additionally, for end caps with weld seams, don’t forget to take into account the impact of the weld coefficient. When performing calculations, refer to the relevant provisions UG-37 to UG-40 in Volume I of ASME VIII. In actual project work, it’s best to carry out calculations based on the specific operating conditions; if you’re not sure, you can also consult professional pressure vessel experts for confirmation~
The head joint passes through the flange; 100% RT for the joint, with a weld joint coefficient of 0.85
What other parameters do you need to determine the value of E1?
Based on the information you provided, “20% RT for other ring seams”, the answer to whether 1.0 can be used for head E1 is: no. At this point, E1 cannot be 1.0; it can only be 0.85. Although the head seam has been subjected to 100% RT, for it to be classified as having an \"E1=1.0\" value, one strict prerequisite must be met: the Class B or Class C circumferential butt welds connected to it must undergo at least one sample radiographic inspection. The requirements for this sampling inspection are clearly specified in clause UW-11(a)(5)(b). The “20% RT for other ring seams” you mentioned is also a type of radiographic inspection, but it is generally considered to be the “sampling radiographic inspection” required by UW-11(b), with the aim of ensuring quality control. This is completely different in nature from the \"sampled radiographic inspection\" required by UW-11(a)(5)(b) as a prerequisite for setting E=1.0 for Class A welds: the purpose is different – the sampled inspection in UW-11(b) is intended for overall control of welding quality ； The sampling inspection per UW-11(a)(5)(b) is specifically intended to \"verify\" the reliability of B/C class welds that intersect with A class welds, thereby \"unlocking\" the eligibility for A class welds to use E=1.0. The rules are different: The number of samples required under UW-11(a)(5)(b) is independent and cannot be used to meet the sampling requirements for any other welds (such as the 20% ratio you mentioned). Furthermore, when calculating the number of samples to take, standards such as UW-52 specify that at least one radiograph should be taken for every 15 meters (50 feet) of weld length. Therefore, merely \"performing 20% RT\" does not meet the requirements for \"sampling radiographic inspection\" specified in UW-12(d), which is a prerequisite for setting E=1.0. Therefore, in your case, the welding joint coefficient E1 for the head can only be taken as 0.85. This is what DeepSeek said; I don’t know what the accuracy rate is, so I’m trying to find professionals on the forum to help answer this question!