what's the difference of "Joint" and "Connection" ? 4

[Abdolrahimi]

Hello everyone
Would you please tell me what's the difference of "joint" and "connection" in ASME code B31.3

Example:
345.2.2 Other Test Requirements
(a) Examination for Leaks. The leak test pressure shall be maintained for at least 10 min and then all joints and connections shall be examined for leaks.

 

[LittleInch]

Not sure if it's in the definitions but joints generally means the bit between each individual pipe (welds, flanges etc) and connections things like tees, branches, screwed items like pressure transmitters.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Abdolrahimi]

Dear LittleInch

I can't find the definition of these words in ASME.

Another example is in code case 185 :
reply
3. All system joints and connections shall be leak tested. Piping welds and joints to be tested
shall be uninsulated and exposed, and shall not be primed, painted or otherwise coated.

Here I think the meanings of welds and joints are also different.

 

[LittleInch]

The overall meaning is quite clear. Why do you want to know the difference?

"Joint" and "connection" are somewhat interchangeable so I can only assume the authors wanted to catch all items.

What it means is that pipe, fittings, vessels and things like pumps or valves don't need testing, this refers to the piping system.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Dhurjati Sen]

Answer to your second post. Piping welds are obviously weld joints while piping joints could be threaded, bonded, etc.

DHURJATI SEN

 

[goutam_freelance]

Refer Sec-VIII-1 UW-15
'UW-15 WELDED CONNECTIONS
(a) Nozzles, other connections, and their reinforcements may be attached to pressure vessels by arc or gas welding.'
So connections are basically nozzles etc. which are used for connecting the vessels to pipings etc.


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[Abdolrahimi]

Dear Dhurjati Sen
A convincing answer, LIKE !

 

[Abdolrahimi]

Dear goutam_freelance
Your perception complemented LittleInch's response.
Thanks

 

[HTURKAK]

You may look to ASME code B31.3 for definition of connection ( branch, equipment conn...) at Chapter I , Scope and Definitions.

Definition of Joint = A connection between two lengths of pipe or between a length of pipe and a fitting.

( reference Piping Handbook NAYYAR ).

Good Luck..

 

[LittleInch]

In the B 31.3 definitions there are several mentions of "joints" and indeed within chapter II, there is Part 4 which runs for 2 1/2 pages all about different types of "joints".

Part 4 Fluid Service Requirements for Piping Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
310 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
311 Welded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
312 Flanged Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
313 Expanded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
314 Threaded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
315 Tubing Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
316 Caulked Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
317 Soldered and Brazed Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
318 Special Joints . . . . . . . . . . . . . . . . . . . .

Thus all these are "joints" and are grouped together.

In code case 185, the committe wanted to specifically note welded joints were not to be covered up as these often have paint etc applied before testing.

Similarly with "connections" there are two critical ones listed:

branch connection fitting: an integrally reinforced fitting
welded to a run pipe and connected to a branch pipe by a
buttwelding, socket welding, threaded, or flanged joint;
includes a branch outlet fitting conforming to MSS SP-97

and

connections for external piping: those integral parts of individual pieces of equipment that are designed for attachment of external piping.





Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Abdolrahimi]

Dear HTURKAK
Great! Thanks

 

[Abdolrahimi]

Dear LittleInch
Like! Thanks Indeed