BPVC Div 1 Thread Allowable (UG-43) 2

[Gavin_UK]

Hello All,
From reading BPVC 2023 Div 1. The only reference I can find for threaded connections is UG-43.
The way I understand this we can only make a connection to the pressure vessel if the thread is listed ASME B1.20.1.
Is this correct? Any help appreciated.
Thanks
Gavin

 

[XL83NL]

Good question. Can’t really answer but chipping in to hear others (expert) opinions.

 

[r6155]

UG 43 is for threaded INTO A HOLE IN THE VESSEL WALL.

For FITTINGS see ASME B16.11

 

[IdanPV]

B16.11 also refer to B1.20.1.

You can use threaded fitting other than NPT provided that the nozzle neck thickness is greater than required by UG-45 or Table UW-16.1 (if UW-16(f)(3) is applicable).
UG-11 and UG-14 may be applicable as well.

 

[Gavin_UK]

Hello All,
To clarify I am looking for holes that go into the pressurised area of the vessel, for example to add a pressure sensor.
B1.20.1 is listed in UG-43, So I know i can use threads here, but they don't include metric threads, which some of my bought in components have.
Where does it say threads to B16.11 can be used?

IdanPV- I dont see how UG-11 PREFABRICATED OR PREFORMED PRESSURE PARTS or UG-14 RODS AND BARS is relevant, can you explain which paragraphs?
Thanks for any advice.

 

[IdanPV]

I thought you wanted to design a nozzle which will be welded to the shell.

As per B16.11, para. 6.3 all fitting shall thread per ASME B1.20.1.

In the company I work for, we produce our own BSP fittings (made of BARS per UG-14) which has the same wall thickness as B16.11 fittings.
Those fitting are complied with our own manufactured standard (required per Figure UW-16.2) and according to UG-11(d).

 

[r6155]

Diameter of the pressure sensor?

 

[Gavin_UK]

There are a couple of different things. The smallest in diameter is an M10 thread at the moment. There are a couple of different threads though, and thing might change in future, so knowing where is states the rules so I can understand them would be great.
Thanks

 

[Geoff13]

The Code addresses pressure retaining components. Thus a nozzle that is threaded into the vessel wall would have to meet UG-43, since the neck would be pressure retaining.

If I understand your description you just want to have a partial depth threaded hole for attaching a sensor. I would say this threaded hole is outside the scope of the Code, since it isn't pressure retaining, and thus can be any imperial or metric thread pattern you want.

 

[Gavin_UK]

Hi Geoff, thanks for your answer. When you say partial depth what do you mean? To take it to extreme, if I only use a small number of threads on the sensor the pressure could be enough to damage these and blow the sensor out. So I am surprised if this isn't covered in Div 1 somewhere, but UG43 seem to only allow me 1 type of thread which seems too restrictive when using bought in sensors.

 

[IdanPV]

Refer to Interpretation Number : VIII-1-89-122

Question: When designing a threaded hole in a vessel wall according to UG-43(e), may a National Standard or International Standard for pipe threads other than ANSI B1.20.1 be used?

Reply: The Committee recognizes that its Codes and Code stamped equipment are used in countries where thread standards other than ANSI B1.20.1 may be required. Thread standards which do not conform to ANSI B1.20.1 may be used by agreement between User and Manufacturer under the provisions of U-2(g) of the Code provided all other Code requirements for threaded connections are met.

That shall answer your question.

Good luck.

 

[Geoff13]

Oops, I didn't think carefully enough about you saying "pressure sensor". This will of course require a through hole. Let me start fresh.

I'm used to see small flanged nozzles labelled as pressure sensors. Presumably these sensors come with standard B16.5 bolted flange for attachment.

The Code cannot cover all possible scenarios. If I wanted to use a metric threaded pressure sensor screwed into a threaded hole in the shell I would say this falls under U-1(a)(3) and U-2(g).

However if you truly believe the sensor can be blown out by the pressure then I don't think you're meeting U-2(g).

 

[Gavin_UK]

IdanPV, thank you, I didn't realise this list of interpretations existed. I will check on that for future questions.
Anyone know why don't these interpretations get rolled into updates on the Code? I appreciate every one cant be added, but in my mind this one is actually changing the code not an interpretation.

 

[r6155]

The pressure sensor thread is????

 

[Gavin_UK]

The pressure sensor thread is????

M10, but I also have other items with different threads so I wanted to understand the rules.

 

[r6155]

Thread standard of inch thread: PT is the abbreviation of Pipe Thread, is 55° seal tapered pipe thread, belongs to the Wyeth Thread family, mostly used in Europe and the Commonwealth countries. Commonly used in water and gas pipe industry, the taper is 1:16.

– Thread standard for American thread: NPT is the abbreviation for National (American) Pipe Thread. It belongs to the American standard of 60° taper screw thread, used in North America.

Continue reading in internet.

 

[IdanPV]

@r6155, again you are not helping.

The question is specifically about UG-43(e) and the types of threaded connections that are allowed.
As previously stated, UG-43(e) pertains to threaded connections that comply with B1.20.1, which may be screwed into a threaded hole in the vessel wall.

Interpretation Number : VIII-1-89-122 allows the use of other types of thread standards which do not conform to B1.20.1.

I think @Gavin_UK already got answers to his questions.