Pressure Rating Conversion

Cross-reference ASME Class, EN/ISO PN and JIS K flange ratings for preliminary substitution screening — with a clear reminder that these designations are not interchangeable pressure ratings.

Quick rating cross-reference

Find nominal equivalents across ASME, EN/ISO PN, and JIS K flange rating standards.

ASME / EN / JIS

Select ASME Class

EN / ISO PN Equivalent

PN 20 (≈ PN 16–25)

JIS K Equivalent

10K

Usage Note

Most common low-pressure rating; PN 16 flanges are frequently substituted where dimensions and rating permit.

Cross-reference table

Showing 7 rating classes

Nominal cross-reference between ASME Class, EN/ISO PN and JIS K flange ratings
ASME Class	EN / ISO PN	JIS K	Usage & Interchangeability Note
Class 150	PN 20 (≈ PN 16–25)	10K	Most common low-pressure rating; PN 16 flanges are frequently substituted where dimensions and rating permit.
Class 300	PN 50 (≈ PN 40)	20K – 30K	General medium-pressure service; PN 40 is the usual European counterpart.
Class 400	PN 64	—	Less common; often superseded by Class 600 in project standards.
Class 600	PN 100	40K – 63K	Common high-pressure rating for hydrocarbons and steam.
Class 900	PN 150	—	High-pressure service; verify availability of matching PN flanges.
Class 1500	PN 250	—	High-pressure service, typically ring-type-joint facing.
Class 2500	PN 420	—	Highest standard B16.5 class; RTJ facing, heavy flanges.