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PN40 Rated Loose flange and stub end connection

The customer asked us about the PN40 rated loose flange and stub end connection:

In my quest to forge a contrivance, I’m sculpting from a solid bar, crafting a model with a stub end joint. The central premise here is to create an interface where a loose plate slips effortlessly over the body of this prototype, forming a snug lap joint. The motivation behind this design choice stems from our need for the loose flange to revolve, enabling accurate alignment of bolt holes. Moreover, we wish to steer clear of any welds between the stub end and the lap joint flange, ensuring the possibility of disassembly if ever required.
Standards set by ASME approve of the combination of a stub end and a lapped flange for pressure ratings ranging from ASME #150 to #600, and even higher. However, the EN 1092-1 standard only supports a loose plate and a lapped pipe end (Type 02 & Type 33), only up to a pressure rating of PN16.
The connection I seek is specifically for a PN40 pressure rating. This leads me to ponder upon the other potential connections of a similar nature, namely:

  • A loose plate flange paired with a weldring neck (Type 02 & 35);
  • A loose plate flange in combination with a weld-neck collar (Type 04 & 34).

Interestingly, both these combinations can withstand a pressure rating of PN40. My curiosity lies in understanding whether these two combinations necessitate any welding between the stub ends (Weldring Neck (35), Weld-neck collar) and the loose plate flange once the bolt holes have been accurately aligned?
To put it simply, are these two combinations designed to be taken apart once fully assembled? The assumption here is that the loose plate can easily slide off the pipework without any issue.

20230520001916 15189 - PN40 Rated Loose flange and stub end connection
Despite diligently scouring through the EN 1092-1 documentation, I’ve yet to unearth any conclusive evidence regarding the proper assembly methods for these combinations. Any light you could shed on this enigma would be profoundly appreciated.


I think You have to use type 32 weld-on collar plate for your purpose.

20230520002633 71305 - PN40 Rated Loose flange and stub end connection

PN 40 flanges



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