What Is EN 1092-1?

EN 1092-1 is the European standard for steel pipe flanges. It covers flanges from DN 10 to DN 4000 in pressure ratings PN 2.5 through PN 400. Widely used in Europe, the Middle East, Africa, and Asia, EN 1092-1 defines a completely different dimensional system from ASME B16.5—the two standards are not interchangeable.

What EN 1092-1 Covers

Parameter	Detail
Size range	DN 10 to DN 4000
Pressure ratings	PN 2.5, 6, 10, 16, 25, 40, 63, 100, 160, 250, 400
Flange types	WN (Type 11), plate/SO (Type 01), blind (Type 05), threaded (Type 13), loose (Type 02), lapped (Type 04)
Facing types	Type B (raised face), Type D (tongue), Type E (groove), Type F (spigot), Type G (recess)
Materials	EN 10222 (forged), EN 10253 (cast)—e.g., P250GH (CS), 1.4301/1.4404 (SS)
Standard parts	EN 1092-1 (steel), EN 1092-2 (cast iron), EN 1092-3 (copper), EN 1092-4 (aluminum)

PN Rating System

PN (Pression Nominale) is the European pressure designation. Unlike ASME classes, the PN number represents the approximate pressure rating in bars at ambient temperature.

PN Rating	Approx. Pressure @ 20degC	Rough ASME Equivalent
PN 10	10 bar (145 psi)	Below Class 150
PN 16	16 bar (232 psi)	Class 150
PN 25	25 bar (363 psi)	Between 150 and 300
PN 40	40 bar (580 psi)	Class 300
PN 63	63 bar (914 psi)	Class 600
PN 100	100 bar (1450 psi)	Between 600 and 900
PN 160	160 bar (2320 psi)	Class 1500
PN 250	250 bar (3625 psi)	Class 2500

These are approximate equivalences. Actual pressure-temperature ratings differ between EN and ASME due to different material strength bases.

Common Mistake

Assuming PN 20 equals ASME Class 150. While PN 16 and PN 20 flanges are sometimes used as “equivalent” to Class 150, their bolt patterns, ODs, and thicknesses are different. EN and ASME flanges cannot be bolted together without adapter flanges.

Flange Type Designations

EN 1092-1 uses a numeric type system:

EN Type	Description	ASME Equivalent
Type 01	Plate flange (flat, no hub)	Slip-on
Type 02	Loose plate flange	Lap joint
Type 04	Lapped flange	Lap joint
Type 05	Blind flange	Blind
Type 11	Welding neck flange	Weld neck
Type 12	Hubbed slip-on	Slip-on
Type 13	Threaded flange	Threaded

Pro Tip

EN 1092-1 Type B1 raised face has a height of 2 mm for PN 10-40, compared to 1.6 mm for ASME B16.5 Classes 150-300. Even the raised face heights are different between the two systems, which affects gasket selection.

EN 1092-1 is referenced by the European Pressure Equipment Directive (PED 2014/68/EU) and carries CE marking requirements for flanges sold in the EU market.

Read the full guide to flanges