ASME B16.5 design confirmation

[rmerlob]

Sorry If I sound like a bit of a newbie here this is not really my line of expertise.

Is this slip-on flange design correct for a NPS20 inch pipe holding 1300 psi?

Regards,

RM

 

[SnTMan]

A) At what temperature?
B) I doubt I would use any slip-on flange at that pressure.

Regards,

Mike

 

[rmerlob]

Thanks for the response Mike,

A) Its ambient temperature around 25C.

B) Could you elaborate why you wouldnt use it, and why would it be your first choice?

About that I also have a question on the standard that might be related, the copy I have says "slip on welding(NPS 1/2 to 2 1/2 only)" (right below the drawing on page 90)

But then they go ahead and give dimensions for them on all sizes, so its contradicting or I misunderstand.

Again thanks so much for the input.

 

[rmerlob]

typo...... B shouldave read

Could you elaborate why you wouldnt use it, what whould you use and why would it be your first choice?

 

[SnTMan]

rmerlob, the note would appear to apply to socket-weld flanges only (my older copy says to 3 NPS).

For a slip-on flange the welds will be two fillet welds (corner joints) and they would probably be rather large. The stress concentrations are not especially desirable. They are hard to NDE. I would more likely use a weld-neck flange and butt weld it. This weld can be x-rayed.

Regards,

Mike

 

[rmerlob]

1) Thats very weird, in mine it seems to be pretty clear (see attached) but why would they give you the dimensions then.

2) yes I guess being able to x-ray it is a big plus.

Setting that aside for a bit did I use the standard correctly?

I mean ambient temperature+1300 psi+ASTM A516 gr 65+NPS20 gives you that flange?

I just want to make sure that if need be I can use the same process to use a weld-neck flange and be confident I'm doing it right.

Regards,

RM

 

[rmerlob]

BTW, of course I'm going to seek experienced help a bit later, this is some pre-project stuff, actually we have make an offer.

 

[SnTMan]

rmerlob, 1) As I said, my copy is older. Interesting, I'd like to get a look at a current one.
2) Yeah, I'd say you read it right. Material, temperature, read off a pressure.

Good luck,

Mike

 

[rmerlob]

Thanks.

 

[XL83NL]

Your attached dwg says B16.5-2003. Note that the latest edition of B16.5 is 2013.
Depending on your contract date, you'll probably have to stick to B16.5-2009.

 

[rmerlob]

Thanks xl83nl, do you know what differences the 2013 and 2009 edition has regarding this subject?

 

[XL83NL]

Dont know

 

[doct9960]

rmerlob,

The material specified on your drawing is ASTM A516 Gr. 65. This is a plate material.

Plate material is only allowed for blind flanges and reducing flanges without hubs. Please read the following sections in ASME B16.5:
Paragraph 1.1(b)
Note (b) in Table 1A
Paragraph 5.1

 

[rmerlob]

Thanks doct very helpful