[garzabla]

I have just started working for a company in Canada who are using PN numbers instead of normal ASME Flange ratings

For example they quote FLANGE WNRF NPS 12 PN 100 12.7mm WT

In ASME a PN 100 is Equivalent to ASME 600#
It seems confusing and unnecessary to give only this PN description when everyone is used to the “normal” rating description of 600#

It is even more confusing that in the European standard EN 1092-1 (old DIN) an ASME 600# Flange is equivalent to an EN 1092-1 PN 40 Flange

At least this makes some sense as the European PN units are bars and 40bar=580psi

Why is the ASME PN system different or even used?

[P V]

[quote=”garzabla” post=7171]Jop I don’t think your table is the European Standard, as I said above – In the European standard EN 1092-1 (old DIN) an ASME 600# Flange is equivalent to a PN 40 Flange.

At least this makes some sense as the European PN units are bars and 40bar=580psi
So what is the basis of your table where ASME 600# is equivalent to PN 100?[/quote]

The aforementioned conversion can found here. It also matches the image provided by Anton.

[quote=”from ‘engineeringtoolbox.com'”]Piping Class Ratings based on the ASME B16.5 – Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard – class and the corresponding ISO 7005 PN (Pression Nominal*) ratings[/quote]

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