Can I Pressure Test a flange past it's Rated Pressure 4

[ljp01]

Hi All,
I'm trying to find out if I can hydrostatically pressure an ANSI 300 lb (PN50) flange, past it's pressure rating of PN50?

I have a stainless steel pipe with ANSI 300lb flanges on it. The operating conditions below 50 bar, however I need to undertake a hydrostatic pressure test (with water) approximately 20% above 50 bar.

Does any one know what the test pressure of these flanges and/or if there are any links/references that indicate what I can test the flanges to?

 

[stanier]

Check out ASME B31.3 design section. you can see that with the owners permission you can exceed the design pressure for short durations and limited number of hours per year.

"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.

http://waterhammer.hopout.com.au/

 

[BigInch]

ANSI flanges can be hydrotested to 1.5 times design pressure.

Let your acquaintances be many, but your advisors one in a thousand’ ... Book of Ecclesiasticus

 

[TGS4]

[rant]There is no such thing as an "ANSI" flange. The proper designation is ASME B16.5 or ASME B16.47, or AWWA C207. Furthermore, the ASME B16.5 and B16.47 flanges are not "300lb" flanges - they are deemed "Class 300" flanges. Colloquially, we may refer to the antiquated term "pound" when refering to these flanges, but the proper term is "Class 300".[/rant]

You will find all of the information that you seek in the Standard that these flanges come from. If you have an ASME B16.5 flange, then you can find your answers in ASME B16.5. Buy it, read, and come back here if you have questions.

 

[Duwe6]

A lot of refineries and chemical plants, including mine, perform "Full Flange" Hydro's. That is 1.5 times the room-temperature rating of the flange as listed in ANSI B16.5. That gives 1080 psig [minimum] for Class 300 SA-105 carbon steel, 900 psig for 304L/316L 300#'s.

As for the rant, all us old guys call 'em ANSI, vs. API flanges. It wasn't all that many years ago that ASME took over the B16.5 spec from ANSI. Watch out for API flanges, totally different bolt patterns and thicknesses.

 

[TGS4]

Good point duwe6 - many piping line classes are limited by the flange rating, which allows you to do just that - test to the RT flange rating (times 1.5, of course).

It wasn't all that many years ago that ASME took over the B16.5 spec from ANSI.

In 1988 it was a joint ASME/ANSI Code. Since 1996, it has been solely an ASME Standard. After 15 years, maybe it's time...

 

[Duwe6]

maybe so, maybe so . . . .

 

[BigInch]

Not. Agreed that ASME may be the current standard, but $1MM says that ANSI flanges do still exist, ... and the question was about ANSI flanges, was it not?

[rant]Answer the question.[/rant]

Let your acquaintances be many, but your advisors one in a thousand’ ... Book of Ecclesiasticus

 

[europipe]

And please ljp, don't mix up 300# and PN50 (whatever that is, in accordance to flanges.)

 

[BigInch]

europipe... on target!

Let your acquaintances be many, but your advisors one in a thousand’ ... Book of Ecclesiasticus

 

[europipe]

por favor B"

 

[JLSeagull]

Until the standard became ASME B16.5 with update in 1996 ANSI was correct. I too prefer the current standard name for new material. I bet some flanged lines operating around WWII still operate.

 

[SNORGY]

Well...

It's a darn sight easier to figure out "ANSI B16.5 vs ASME B16.5" than it is to figure out that whole, sordid, "...Class 2000 vs 2000# vs CWP vs WOG vs whatever else..." thing.

But that's just me...

Regards,

SNORGY.

 

[TGS4]

BigInch - you are indeed correct. However, it would certainly be helpful in these types of discussions to be accurate when referring to Standard flanges. I agree that pre-1988, they were indeed ANSI flanges. I have seen many of them stamped as such.

Many users here, though, are careless (or ignorant of the differences). Pre-1988, Standard Flanges would be listed as ANSI. Flanges manufactured to the 1988 Edition would be listed as ANSI/ASME. Flanges manufactured to the 1996 and newer Standard would be ASME.

Part of my rant was directed at the OP, because they appeared to not understand the whole "Standard / Edition" context of Standard flanges. The answer to their question would be found in the Standard. So, read the Standard. Which is what I directed them to do.

If they indeed do have an ANSI 300lb flange (as stamped on the flange), then they would need to find out from the piping isometric and line class designation table, which Edition of ANSI B16.5 said flange was from, and then they would need to look up that particular Edition of ANSI B16.5 to find their answer. I know what ASME B16.5 says, from 1996 onwards, but not earlier Editions of ANSI B16.5...

If it is new construction, then...

 

[JLSeagull]

Think flange material and temperature too. Some precision could help as 725.1887 psig is a quick conversion of 50 barg. Class 300 flanges depend upon the material. You need a copy of the applicable standards.

Class 300 is suitable at 740 psig and -20 to 100 degree F for ASME B16.5 in castings of A 216 Gr WCB and forgings of A 105 carbon steel. A bit more such as 750 psig is good for A 216 WCC castings. However many other material tables include the working pressure well below 725 psig. Thus you must verify the material type. As an instrumentation and control systems engineer I buy lots of stuff with type 316 SSt. Types A 182 Gr. F316 and A 351 Gr. CF3 are just below your 50 bar suggestion. The multiplier suggested could still apply. Things could go to hell in a handbasket for B 564 Gr. N02200 (rated 240 psig for Cl 300 and only 720 psig at Class 900. B 564 Gr. N08810 etc. may not be quite as bad.

The approximate 1.5 design pressure multiplier mentioned by BigInch for hydrostatic checking of the piping for leakage is correct. You need to know the piping system design pressure etc. and learn more about hydrostatic pressure testing as suggested. Hydrotesting is well outside my knowledge of the piping game.

BTW I could be wrong, right?

 

[dcasto]

]-- we all get excited about the flanges, BUT, a lot of stainless steel lines are of sch 5 and 10 and the line may limit the pressure rateing of the system. Pay attention to yield strenghts too.

 

[rconner]

It may not hurt to mention as well that of course the "flanges" are not the only components involved in flanged pipe joints, and it may be desirable to pay some "attention" as well to the gaskets, as well as bolt combinations also inherently employed (in one example, if bolts that "gall up" are used along with very hard gasketing materials, one might find it hard to hold even low pressures without leakage, let alone tests beyond rated flange pressures!)

 

[stanier]

Amazing how many young engineers have to be corrected about terminology when it comes to flange classesvs lb, ASME vs ANSI, pipe threads etc etc. It pays to be precise and disciplined in all aspects of engineering. If you get slack in terminology then what value any of your other work?

If people use the wrong expressions then it behoves the more knowledgable engineer to correct them.

My pet hate:- people who still refer to HDPE. The third generation PE100 is actually MDPE. Yes, its black and round and tastes the same but it aint HDPE! MDPE has different properties to HDPE and thus if HDPE is specified either the material is non compliant to PE100 standards or if it is HDPE will have reduced life compared to PE100.

"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.

http://waterhammer.hopout.com.au/