How do I convert an ASME class to an equivalent PN?

Indicative only: Class 150 ≈ PN20, Class 300 ≈ PN50, Class 600 ≈ PN100. ⚠️ This correspondence does not account for temperature — the ASME B16.5 pressure/temperature rating chart and the EN 1092-1 nominal pressure follow different logics, and the gap widens at higher temperatures. It does not replace checking the standard's own rating chart, which should always be done before specifying a flange.

Is class 600 available from partner stock?

To check case by case depending on diameter — the most common classes (150, 300) are most readily available from partner stock.

Is the RTJ face possible in ASME B16.5?

Yes, on request — RF and FF remain the default faces of the standard offer.

Why isn't ASME B16.47 (large diameter flanges) offered?

This is an SPS offer choice to stay on the two most requested standards — EN 1092-1 and ASME B16.5 — not a technical limit.

STAINLESS FLANGES · ASME B16.5

Stainless flange ASME B16.5

The ASME B16.5 flange is the reference American standard, expressed in class (150 to 600) rather than a direct nominal pressure. Used on projects with a North American reference framework or process equipment imported from the US.

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What is a stainless ASME B16.5 flange?

The ASME B16.5 flange is the North American reference standard for small and medium diameter piping flanges, expressed in pressure class (150, 300, 400, 600…) combined with a pressure/temperature chart per grade, rather than a fixed nominal pressure like EN 1092-1.

How to choose it?

Class is read off the standard's pressure/temperature chart, not as a simple direct nominal pressure — allowable pressure drops with temperature. Type (slip-on, weld neck, blind) follows the same logic as EN 1092-1.

Available grades

Standard austenitics (304L, 316L) from partner stock; duplex on request for more corrosive networks.

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Applicable standards

ASME B16.5

Partner stock or mill?

The ASME B16.5 flange follows the same partner stock / mill logic as the rest of the stainless piping on the same project.

From partner stock: 48 hours for urgent needs, 5 working days as standard.

We go through the mill when volume and lead time make sense — typically container-load quantities, sometimes less, with a lead time of a few months including transport. That arbitration is ours to make: when buying at source works out cheaper for you, we say so.

Frequently asked questions

How do I convert an ASME class to an equivalent PN?: Indicative only: Class 150 ≈ PN20, Class 300 ≈ PN50, Class 600 ≈ PN100. ⚠️ This correspondence does not account for temperature — the ASME B16.5 pressure/temperature rating chart and the EN 1092-1 nominal pressure follow different logics, and the gap widens at higher temperatures. It does not replace checking the standard's own rating chart, which should always be done before specifying a flange.
Is class 600 available from partner stock?: To check case by case depending on diameter — the most common classes (150, 300) are most readily available from partner stock.
Is the RTJ face possible in ASME B16.5?: Yes, on request — RF and FF remain the default faces of the standard offer.
Why isn't ASME B16.47 (large diameter flanges) offered?: This is an SPS offer choice to stay on the two most requested standards — EN 1092-1 and ASME B16.5 — not a technical limit.