EN 1759 flange for PED (instead of B16.5)

[ElCidCampeador]

Hi,

I have to design a vessel according to EN 13445+PED; previously this vessel was designed according to ASME VIII DIV.1.
I have to use ASTM material + PMA.
Vessel is in stainless steel material and is very simple, a shell from plate with 2 elliptical heads at the ends with some nozzles and flanges.

Now I'm running the previous ASME design in accordance with EN 13445 but I'm having a problem.

A standard flange B16.5 used for a nozzle fails with the new EN calculation ("stresses are greater than maximum allowed"). This because, I suppose, EN considers this flange as "special", so it runs all complete calculation.

A solution that I've found is to consider this flange as standard according to EN 1759, which dimensionally seems to be equivalent to B16.5. In this way, software accept this flange without errors or warning anymore.

If supplier of flanges could certify this flange according to both B16.5 and EN 1759, do you think that this solution could be accepted from third part body who will review calculation for PED?

Thank you

 

[LittleInch]

Does the code 13445 & PED accept ASME B 16.5 flanges as being approved or listed materials which do not need to be designed or reviewed once they are above the pressure rating MAWP of the vessel or not?

If they are accepted as approved items then it's your software which is the issue?

Or just submit it with a note saying according to section xxx.yyy these flanges are considered already accepted.

But this looks to me like a bad thing to do - mixing two different code systems and flanges.

If you "HAVE" to design to 13445, then you need to follow all the recommendations, normative references and allowable materials and codes. If B16.5 isn't listed then you're in trouble according to the letter of the code.

But what does the AI or approval person / body say?

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

 

[ElCidCampeador]

I haven't talked to third body yet, the only thing that I know is that if in the software I select that flange according to EN 1759 (which has the same dimension as per B16.5, i checked), calcs are ok and software doesn't output error or warning anymore. Stop.
So it seems that this solution is valid (software is an international one and validated, but I don't want to spoiler it). My question is simple: has anyone here ever "used" this trick to make acceptable standard flange B16.5 in EN code? Keep in mind that this flange will be certified acc. to EN 1759, so it's not totally unrelated to the EN code.

 

[LittleInch]

Yes, but what does the code say about B 16.5 flanges?

If it isn't a listed component or whatever the EN flanges are called, then doing tricks and inputting false data isn't going to solve the issue.

I'm sure you're correct about the dimensions, but that's not the point here, IMHO.

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

 

[ElCidCampeador]

Ok, I understand your point.

In EN 13445 seems that EN 1759 is not mentioned, but EN 13445-3 par. 11.4.2. says:

11.4.2 Use of standard flanges without calculation
Flanges that conform to an European Standard for pipework flanges may be used as pressure vessel components
without any calculation, provided all the following conditions are fulfilled:
a) Under normal operating conditions, the calculation pressure does not exceed the rating pressure given in the
tables of the relevant European Standard, for the flange and material under consideration for the calculation
temperature.
b) Under testing conditions or exceptional conditions, the calculation pressure does not exceed 1,5 times the
rating pressure given in the same tables, at appropriate temperature.
c) The gasket is one of those permitted by Table 11.4-1 for the relevant PN or Class series.
d) The bolts are of a strength category (see Table 11.4-2) at least equal to the minimum required by Table 11.4-1
as a function of the gasket type used in the connection.
e) The vessel is subjected to loadings of predominantly non-cyclic nature, see 5.4.2.
f) The difference between mean temperatures of bolts and flange does not exceed 50 °C in any condition.
g) The bolt and flange materials have coefficients of thermal expansion at 20 °C that differ by more than 10 %
(e.g. austenitic steel flanges with ferritic steel bolts) but the calculation temperature is < 120 °C, or the bolt and
flange materials have coefficients of thermal expansion at 20 °C which do not differ by more than 10 %.

I suppose that my software has already checked all this points, giving green light for the use of this standard...

 

[LittleInch]

Think this is the killer phrase... "..European Standard for pipework flanges ..."

Mix and matching standard systems is usually doomed to failure I'm afraid so one of:

"I have to design a vessel according to EN 13445+PED" and
"A standard flange B16.5 used for a nozzle "

has to change.

Your or your clients call.

What's the grief factor using EN 1759 flanges?

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

 

[ElCidCampeador]

Mmm but EN 1759 is an european standard, isn't it? I'm not mixing anything because flange is according to an EN standard (and ALSO acc. to ASME B16.5, but in certificate EN will be stated).

 

[LittleInch]

Ok, did a bit more looking at this.

Looks like there was a BS standard basically following B 16.5 called BS 1560-2 and now called EN 1759.

HOWEVER, whilst everything seems to say they are "basically the same dimensions", the world doesn't seem to have anywhere officially speaking that the two are interchangable / identical.

So unless you can find a supplier giving you dual certification and stamped for the same bit of metal, I think you're not going to convince anyone that they are one and the same.

Have you asked any vendors if they are willing to do this? For a price no doubt.

This from the next gen suppliers site and a table which backs up your suspicions.

"One thing to keep in mind is that each calculation code declares which flanges standard can be adopted using the first option when used within a project: this means that a flange can be considered standard only when used within a compatible calculation code. It is not possible for example to use ANSI flanges by their rating within an EN13445 project; similarly, an EN1092-1 or EN 1759-1 flange can't be used by its rating in an ASME project, even if EN 1759-1 flanges have basically the same dimensions as ANSI B16."

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

 

[ElCidCampeador]

I've just found a supplier which will state into certificate the dual standard (EN+ASME), and also without additional costs.
Now I'm in contact with Third Part to understand if he will accept this.

IMO,considering also green light from calculation, unless Notified Body's word, I hope there shouldn't be any problem.

 

[LittleInch]

Great - there shouldn't be any issue as you now have an EN flange both in your calculation and in certificate form.

don't mention the ASME word or it will confuse them.

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

 

[XL83NL]

Shaits. Just made a long post and after submit, it’s gone.

We’ve had something similar. I will go into details tomorrow when I’m at the office and can go through our mail archive, but I think the clue was ISO 7005. That led back to EN1759, and by using some clauses from EN13445 chapter 11 we were good to go.

Huub
- You never get what you expect, you only get what you inspect.

 

[SnTMan]

XL83NL, I've kind of made a habit of copying long posts to a text file before submitting. You know, just in case

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[XL83NL]

Haha yeah I’ve gotten used to that too but I’m on mobile now (iOS) and that’s quite a workaround compared to pc.

As per the first post, I is t understand why you’d want to use ASTM and PMA for an EN13444 vessel. What’s the reason for that? Don’t tell me it’s because the previous version was designed to ASME VII-1 ;-).

Huub
- You never get what you expect, you only get what you inspect.

 

[ElCidCampeador]

As per the first post, I is t understand why you’d want to use ASTM and PMA for an EN13444 vessel. What’s the reason for that? Don’t tell me it’s because the previous version was designed to ASME VII-1 winky smile.

ASTM materials are far easier to purchase for me, so I think I will not change to EN.

 

[ElCidCampeador]

Notified Body has just told me that he will accept flange double certificated as B16.5/EN 1759

 

[XL83NL]

Thats true for some materials, I know from experience. What's your MOC? With ASTM & PMA & B16.5 flange patterns, you're getting yourselves in a heck of trouble if it has to be EN 13445 design.

Huub
- You never get what you expect, you only get what you inspect.

 

[nashki]

Hi,

Can someone explain why EN1795-1 consider material grade up to 2.7 only while ASME B16.5 has material group no. up to 3.19?

I have similar case with this thread

The PV design based on EN13445, MOC is Duplex (X2CrNiMoN22-5-3, 1.4462)

If refer to ASME B16.5, it is same grade with A-182-F51 in material group 2.8

Since, material group 2.8 is not available in EN1759-1

Can someone please share some thought of experience for this case?

 

[davefitz]

I am not sure that the funding for ASME is sustainable ,after witnessing the very low turnout at some ASME conferences. Perhaps the adoption of the funding mechanism used in europe by the EN might be neccesary, or maybe accepting and/or merging with the EN is in the cards.

As far as the B16.5 flanges go, it is my understanding that some B16.5 flanges will not meet the requirements of ASME sect VIII div 1 or div 2 analysis, as they were originally designed "by eye" in the 1930's , way before finite element applications were commercially available. The B16.5 flanges are almost always much heavier and less suitable for thermal cycling in their larger sized flanges than their "compact flange" alternatives that are designed by sect VIII or the EN.

Steam locomoives are in the past, now coal fired boilers are defunct in the US, so it may occur that ASME will fizzle out as well.

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick