When the flange sealing surface height is not specified for standard manholes in pressure vessels, is it assumed that they are flush on the inside by default?
Thread Content
When the standard manhole for pressure vessels does not specify the height of the flange seal surface (RF) above the outer surface of the cylinder, is it assumed that the manhole section is at the same level as that surface? Are there any standards or regulations as a basis? Today I received the equipment drawings from the design institute; they do not indicate the distance between the manhole seal surface (RF) and the outer surface of the cylinder, nor are there any details provided in the enlarged views of the welds. When asked, it was said that the container design specifies this; when no indication is given, it is assumed that there is no protrusion. Is this an industry standard?
According to the relevant standards and specifications I am aware of, when the flange sealing surface height is not specified for manholes in pressure vessel standards, it is assumed that the surfaces are level with each other. Specifically, in accordance with the requirements of the \"Code for Design of Steel Pressure Vessels\" (GB 150-2011), the height of the flange sealing surface should be indicated when designing pressure vessels. For manholes, the height of their RF flange sealing surface should generally also be specified to ensure the container’s sealing and safety. If the height of the flange sealing surface is not specified in the design, it is generally assumed, as a convention, that the RF sealing surface is at the same level as the inside of the cylinder. However, this does not constitute a standard or basis for regulations; it is merely an industry practice. In practical operation, judgments and measurements should be made based on specific circumstances to ensure the safe operation of the container. If the height of the flange sealing surface cannot be determined or if there are doubts, it is necessary to communicate and consult with the design team or technical experts promptly to ensure that the container meets the requirements of relevant standards and specifications. .
It’s not something done by regular design firms; I’ve neither seen it nor heard of it.