PD5500:- acceptable flange standards

[stephenebrady]

We are designing a PV to PD5500. The Vessel is for Korea where the adjoining pipework will be fitted with JIS B2210 20K flanges. Therefore we require a compatible flange to be connected to our vessel branches.
However, PD5500 section 3.8.1 allows the use of BS1560, BS4504, EN1092 and ANSI B16.5 standard flanges only.
Does this mean that we have to calculate the flange thickness to PD5500??....even for 1/2" to 8" sizes??
Seems a little nonsensical.

 

[johnnymist2003]

Hi,
In my opinion, PD 5500 will only allow you to use flanges of standards RECOGNISED by PD 5500 to ensure that what lies within the battery limits of the vessel (normally the first pipe flange joint) will be sufficiently safe.That is not to say that there may be other flange standards that are safe, it just means that they are not listed as suitable for use in PD 5500.If one applies the Rules to the letter, then I suppose you would need to check the flanges as "non-standard" flanges in accordance with PD 5500.One must also remember that not only the design, but also the methods and materials of manufacture, NDE, etc. of the flanges must also be considered. However, if one looks at the problem more logicaly, piping flanges are normally manufactured and tested to a standard. At the end of the day, if the piping flange connected to your vessel flange is suitable for the same design pressure and temperature as the vessel, then why should the one attached to the vessel fail? Can you not get the end user to fit the flanges, thus your battery limits terminate at the nozzle neck stubs?Have you contacted the relevant inspection authority and asked for their advice?If you do fit flanges in accordance with PD 5500 recognised standards, then possibly the end user can manufacture a spool piece to convert from your flange to their pipe flange.I'd definitely get the buy-in of all concerned before deciding which route to go, though.
John

 

[roca]

John
You beat me to it as I was going to suggest the same as you - ie supply ythe vessel with a stub-end and get the client / site contractor to fit / weld the JIS flange to the vessel stub end. Only issue I could maybe see here is if the vessel has been sujected to PWHT - a local PWHT on the weld would need to be applied....???
It is also surely up to the client / local authorities in Korea as to whetehr they will accept a vessel designed to BS500 fitted with JIS flanges. I have no experience with JIS flanges and I am sure that they are of equivalent or even better pressure / temp rating to the ones in ASME B16.5