ASME B16.11 9000# fittings 1

[SNORGY]

Hi all.

Is there such a thing as a published pressure versus temperature rating table for 9000# ASME B16.11 fittings and, if so, where can I find it?

Many thanks in advance...

Who is right doesn't matter. What is right is all that matters.

 

[XL83NL]

No. The only way (I can think of this) is to use the equivalent wall thickness of Cl 9000 fittings (which is Sch XXS per B16.11 table 7), and convert this to a p,T-rating. The variables in the equation would be;
- material
- diameter
- temperature

Hence I imagine that you'd get 1 table per material, with the diameters as columns and the temperature as rows, or vice versa. At least, that how Ive made mine.

 

[SNORGY]

Thanks, XL83NL. I have come across such tables for 2000#, 3000# and 6000# fittings, each split into 5 material groupings, although I have not as yet back-derived them using the approach you describe. The tables I have come across appear somewhat silent as to their source; they might indeed have been calculated by their respective publisher(s). I'll go through the exercise and tinker with it tomorrow.

Who is right doesn't matter. What is right is all that matters.

 

[XL83NL]

What I have recently have done, and where this calculation could also be done with, is made a program in Excel with all ASME B31.3 stress tables, tables for pipe sized & dimensions (B36.10 & 36.19 combined), and other relevant 31.3 tables such as those for Y and W. I have combined these together such that with limited input (material, size range, corrosion allowance, max p & T) the user can calcualte the p,T-rating for a certain pipe spec based on B31.3 rules. The program allows for making the spec flange limited, and will autoamtically determine the required B16.5 flange table number and pound class rating, if you like. It took me less than 1 week to make, while Im not that much an expert in Excel (using VLOOKUP can sometimes be quite challenging to me).

The tables (with p,T-ratings) you are after is exactly what Ive made my program's output to, so with that in mind I think the above could be done within a few hours of Excel work.

 

[LittleInch]

Section 2.1.1 seems to state that the
"Design temperature and
other service conditions shall be limited as provided by
the applicable piping code or regulation for the material
of construction of the fitting.",

Hence throwing it back on the designer and supplier of the particular material. If you base it off XXS material of the same type to B31.3 or whatever you're using you shouldn't go wrong IMO.

They don't actually publish a 3000 or 6000 pressure temperature table either.



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

 

[SNORGY]

XL83N:

Parallel universe...that's what I'm in the midst of doing right now. So, a fittings manufacturer had published the tables I mentioned, so I was contemplating using them if I could first verify them. Otherwise I can go through the ASME B31.3 Code methodology and get the small bore pipe ratings that I need and match the ensuing wall thickness into the fitting rating that I need via 16.5 which I have done. I could also get the stress values for the materials via Table A.1 and develop my own P, T tables, it would just take me a bit of time. I just wanted to make sure I wasn't missing something.

LittleInch:

Yes, you are correct, I could find no such published tables from an official source or Code or Standard. I just found it odd that this particular supplier's catalogue went to great lengths to list the P, T ratings for 2000#, 3000# and 6000#, but not for 9000#. I'll see if I can verify the data tomorrow. I was looking for a short cut if a reliable one was readily available. Meanwhile, what I've done appears to be working.

I must say, I hope this is the last company piping specification I ever have to write / revise. I've done about 5 of them now and I find it extraordinarily tedious and irritating.

Who is right doesn't matter. What is right is all that matters.

 

[XL83NL]

SNORGY, if you like I can do a calculation for you and post results here. We can at least verify if our methods yield the same result. All I need is the material grade, size range, temperature range and corrosion allowance.

 

[SNORGY]

XL83NL:

This is the table - or one of them - I found that I was referring to:

https://cdn.shopify.com/s/files/1/0...for_Pressure_Fittings.pdf?4864146049737822751

And this one (Table 3):

http://pusanfitting.com/products/pdf/Forged_Fittings04.pdf

My intent was to verify these tables and then extend them to 9000#. I have already entered all of the ASME B16.5 flange ratings tables into my spreadsheet and expanded them through interpolation between the listed temperatures. I have also built the logic in there to pick the correct fitting for the threaded or socket welded pipe based on the B16.11 tables. I have incorporated the considerations with respect to the adjustment of "y" from B31.3, and I am using Barlow's equation from which to establish the initial guess. My aim is to do the wall thickness calculations per B31.3, then do the (INDEX(TABLE,VLOOKUP{...},HLOOKUP{...}) functions for flanges and fittings to specify which component limits the design. Some time in future, I will probably pull the (P,T) data for the more common material specifications we use in Table A.1 so that I won't need to manually enter "Sc" and / or "Sh", but for now (today and this weekend), I just want to finish the Piping Specification that I'm working on. The tool in its present form is good enough that my results match, line for line, those thicknesses and materials specified in several reputable "go-by" specifications that I have on hand. That said, I would be more than happy to send you some odd ones for spot-checking; one that always seems to come up is 600# ANSI class in 3" NPS...SCH 40 vs SCH 80...companies here have been arguing that one for decades.

Who is right doesn't matter. What is right is all that matters.

 

[XL83NL]

Hi SNORGY, some questions.

- Im not sure where B16.5 comes in wrt your issue of the 9000# fittings. Or are you comparing the fitting with B16.5 flanges (and other fittings) to find out which fitting limits your spec?
- Sc and Sh; I assume you are referring to the stress allowable from table A-1 for the design or hot condition (sub h), and at ambient (or cold) temperature (sub c)? Sc and Sh have other meanings acc. the nomenclature of B31.3.
- sure, Ill make a snapshot. So, you want the rating for 3" pipe in Sch 40 vs Sch 80. Which material, and whats the corrosion allowance? As you are referring to 3" Sch 40 vs 3" Sch 80, I have no idea with the ANSI 600# has to do with it. There's no such thing as an ANSI 600# class. Also please note it's written as ASME B16.5 Cl. 600 nowadays (actually, since the 70's or so, but most people dont know).

 

[SNORGY]

XL83NL:
- Yes, that is what I am trying to do;
- Yes, Sc and Sh are intended to be those variables in ASME B31.3 Table A.1;
- *THAT* misunderstanding is, of course, my "blinded by involvement" mentality in action - how the heck can I expect you to assume A-106-Gr. B SMLS at 38 C with C.A. = 1.6 mm? <-- LPS for that...

Agreed on the last point...I said "ANSI" not "ASME" which was incorrect, and yes, the intent is to determine whether it is 3" Sch 40 or 3" Sch 80 that ought to be specified. (I say Sch 80...). I'd give you an LPS for that one, too, but I can only give out one at a time.

Who is right doesn't matter. What is right is all that matters.

 

[XL83NL]

Ill follow up on Monday when I'm back at the office.

 

[XL83NL]

Here it is. I have not taken the Weld Joint Strength Reduction Factor into account. Only @ 475 °C the flange rating dominates the pipe rating for 3" 40S; however, I wouldnt use A105N flanges at 475°C and always limit these type of CS specs at 400-425 °C. Therefore, I think 40S suffices for NPS 3".

 

[SNORGY]

XL83NL,

Thank you so much for this check, I'll review shortly to see if my thoughts are in alignment with yours.

Who is right doesn't matter. What is right is all that matters.

 

[KevinNZ]

I would take an other approach. No need to know what the pressure rating of the fittings are. You just know that as good as or better than the pipe.

1. For each project design the piping and work out the required pipe SCH
2. Choose the fittings that match the pipe SCH (and material)

 

[SNORGY]

XL83NL,

Thanks, my numbers agree with yours, pretty much exactly. I think the issue in the past was in the quick estimation by some of hoop stress based on pipe OD (which is really the "pressure design stress") in the numerator. I don't know why some people keep doing it...but apparently they do...then the use of Barlow's formula in CSA Z662 further muddies the waters...

To me, it's technically not true to equate hoop stress with pressure design stress, but it's what some people have tended towards doing.

In the case discussed, the thickness determined in accordance with ASME B31.3 Equation 304.1.2 (3a) gives rise to a surplus t of 0.007 mm. but a "pressure design stress" of 141,657 kPa, or 102.7% of the Sa value.

But none of that was ever my issue in the past. My issue in the past was that, in a size range of 2" NPS and higher, it was an eyesore *to me* to have 3" NPS as SCH 40 and everything else as a higher schedule. But...it is what it is. If that's what people want in their specification for a given line class, then it does meet Code. Just because I wouldn't put it in *my* specification doesn't mean they can't put it in *theirs*.

Who is right doesn't matter. What is right is all that matters.

 

[XL83NL]

Well, if you can limit the spec 1.5 mm CA, and let the temperature range go to max 425 °C, you can use 40S for 1/2", 3/4", 1" and 1.1/2", 2.1/2" and 3". 80S is to be used for 2" and 4" ÷ 8". At 10" and beyond Im at Sch 100, assuming it's all seamless. You then have a flange limited spec.
The only issue with this spec would be that 1.1/2" 40S, @ 0°C,would be limited to 101.4 bar(g0, whereas the flange is limited at 102.1 bar(g); a difference I would care about.