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# PN 40 ANSI Class 300

01/16/2009 4:24 AM

Can anyone give me the equivalence of PN 40 to ANSI class? I need a standard to confirm the relatioship. Thanks in advance.

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Guru

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#1

### Re: PN 40 ANSI class 300

01/16/2009 5:48 AM

PN40 is good for 40barg at room temperature and must be derated at higher temperatures.

ANSI works the other way - ANSI class 300 is OK for 300 psig at about 840°F and can go to 740 psig at room temperature.

Pressure/temperature data for both is on the web.

Cheers...........Codey

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#2

### Re: PN 40 ANSI Class 300

01/17/2009 2:39 AM
 Flange Class 150 300 400 600 900 1500 2500 Flange Pressure Number, PN 20 50 68 100 150 250 420

From that table and for Flange Pressure Number PN 40, I prefer if you select ASME/ANSI Flange Class 300#, Please see the following CR4 Thread: PN numbers vs. valve class in ASME standard.

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#3

### Re: PN 40 ANSI Class 300

01/17/2009 11:22 AM

Dear sir,

Table given by you is correct , I think in ' NFE' and 'CSA' standards as per this tble PN numbers are given.

PN is pressure in Kg / Cm. sq. and class is pressure in lb / inch , so one can calculate exact conversion of PN (kg/cm.sq.) to lb / inch , and deside which CLASS is nearest to PN and visa versa.

I have mailed you on 01/09/2009 5:09 PM about ASME B16.5 - EN 1759 . Request you to reply for same.

Thank you.

V.D.DEODHAR.

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#4

### Re: PN 40 ANSI Class 300

01/17/2009 11:54 AM

Neither Class means psi nor PN means Kg\cm2, because Class or PN are just a categorization or a family name called for a specific group of flanges. The determination of Class or PN depends on 3 parameters: Flange Material, Design Pressure and Design Temperature.

So, the Class or PN for such a flange at certain design condition (pressure & temperature) can be differ from the Class or PN of the same flange designed at the same condition when fabricated from another material. Therefore, no way to calculate or to make a conversion between PN in Kg/cm2 and Class in psi, nor to make an interpolation, because they are not a values.

For more clarification for that point, please see the CR4 Thread Pound Rating.

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#7

### Re: PN 40 ANSI Class 300

01/19/2009 4:05 AM

Hello Abdel

I'm not sure you're right about the figures representing classes and having no meaning as pressures.

On the PN** system, the ** is the design pressure in barg. As you say, there are changes for different materials, but it's only the thickness, to account for variations in design stress.

On ANSI, the class is the design pressure in psig. Admittedly, the elevated temperature at which this pressure applies seems rather arbitrary (and it varies with the pressure class), perhaps somebody can post an explanation?

Incidentally, in UK, if using ANSI/ASME, and the designer needs a pressure say 250 psig (at room temperature) he'll often go for next higher class, Class 300, ignoring or being unaware of the fact that Class 150 is OK for 285 psig. I'd be surprised if it doesn't happen in US as well.

Cheers.....Codey

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#8

### Re: PN 40 ANSI Class 300

01/19/2009 4:27 AM

I'm not sure you're right about the figures representing classes and having no meaning as pressures.

Oh, please be sure that I'm right, in the same time you have the right to trust me or not.

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#9

### Re: PN 40 ANSI Class 300

01/19/2009 4:35 AM

I've tried, but I can't, sorry ! I was trying to be tactful.

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#10

### Re: PN 40 ANSI Class 300

01/30/2009 11:47 AM

Dear Codemaster,

The following PDF file introduced by our friend dincon, post #9 in CR4 Thread Pound Rating, may be including such satisfaction to you: http://www.ebaa.com/pdf/pdf/FL-01.pdf.

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#11

### Re: PN 40 ANSI Class 300

02/02/2009 4:06 AM

OK thanks Abdel.....Codey

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#5

### Re: PN 40 ANSI Class 300

01/17/2009 12:24 PM

I have mailed you on 01/09/2009 5:09 PM about ASME B16.5 - EN 1759 . Request you to reply for same.

Sorry, I don't able to open your file ASME B16.5 - EN 1759 , and the following message is created at every trial.

# Problem! You are attempting to do something that is not permitted.

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#6

### Re: PN 40 ANSI Class 300

01/18/2009 3:00 AM

Yes, by comparing between ASME B16.5 and EN 1759 (or any other codes), certainly there is a difference in dimensions between any code and the other. For example by comparing between ASME B16.5 and EN 1759 as clearly noted from the tables, we noticed a difference in dimensions may be exceeded 5 mm. For that reason, we have to specify only one code to be applied in our designs. And as I stated before in many posts, there is nothing called equivalent between codes/standards.

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#14

### Re: PN 40 ANSI Class 300

06/23/2011 1:45 PM

Can you email comparison between ASME B16.5 - EN1759 to me too?

Regards

Milind Nene

Anonymous Poster
#12

### Re: PN 40 ANSI Class 300

08/26/2010 11:37 AM

Anonymous Poster
#13

### Re: PN 40 ANSI Class 300

11/20/2010 4:02 AM

Can anyone give me the equivalence of PN 40 to ANSI class? I need a standard to confirm the relatioship. Thanks in advance.

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