EN 1092-1 Type 11 PN 40 Weld Neck Flange — Dimensions, Weights & Bolting

It is a weld neck flange made to the European standard EN 1092-1 in nominal pressure class PN 40. In EN 1092-1, “Type 11” is the designation for the weld neck (welding neck) flange — a flange with a long tapered hub that is butt-welded to the pipe. PN 40 is rated for roughly 40 bar at room temperature, and the chart on this page covers DN 10 to DN 600.

PN stands for “Pression Nominale” — the nominal pressure class. A PN 40 flange is rated for a maximum working pressure of about 40 bar at room temperature, with the exact allowable pressure depending on the material group and falling as temperature rises, per the pressure-temperature tables in EN 1092-1. The PN series runs 2.5, 6, 10, 16, 25, 40, 63, 100, 160, 250, 320 and 400.

PN 40 is the standard process class: saturated and superheated steam, gas lines, thermal oil, chemical process duty and boiler auxiliaries in the 25–40 bar band. It is also the small-bore default — because PN 10, 16 and 25 borrow its dimensions below DN 50 (and PN 25 up to DN 150), stockists carry small EN flanges almost exclusively as PN 40.

EN 1092-1 gives each flange construction a type number — plate (01), loose (02/04), blind (05), hubbed slip-on and threaded (12/13), integral (21) and collars (32/34) — but the chart on this page is edited down to the weld neck alone. It lists the D, K and L mating dimensions with bolting, which are shared by every type of the class, plus the Type 11 columns: neck OD A, thickness C2, lengths H2 and H3, neck diameter N1, radius R and neck wall S.

In duty they are close: Class 300 allows roughly 51 bar for A105 at ambient temperature and PN 40 roughly 40 bar, so specifiers treat them as rough counterparts. But the flanges are not interchangeable — EN 1092-1 uses DN sizes, metric bolting and its own bolt circles and facings, while ASME B16.5 uses NPS sizes and imperial bolting.

The PN 40 Type 11 series runs from DN 10 to DN 600. Uniquely, this chart also serves the lower classes: PN 10 and PN 16 use these dimensions for DN 10–40, and PN 25 uses them all the way to DN 150 — so a small-bore EN weld neck flange is almost always, dimensionally, a PN 40 flange.

From the weight columns in our chart: A DN 50 about 3.1 kg (6.9 lbs), a DN 100 about 6.9 kg (15 lbs), a DN 200 about 22 kg (48 lbs), a DN 300 about 50 kg (110 lbs). These are approximate carbon-steel weights calculated from the standard dimensions with a standard bore — actual weight varies with the bore and material.

Form A flat face, Form B1 raised face (standard), Form B2 smooth raised face; tongue/groove and spigot/recess (Forms C–F) on request. State the form required — and the gasket it must suit — on your enquiry.

The bore is machined to match the inside diameter of the mating pipe so the joint has a smooth, unrestricted flow path and a clean butt weld. State the pipe wall thickness or internal diameter (or the pipe standard and series) with your order — the chart's S column gives the preferred neck wall thickness for each size.

We manufacture them in carbon steel A105/P250GH and low-temperature A350 LF2, stainless steel 304/L (1.4301/1.4307), 316/L (1.4401/1.4404), 321 (1.4541), 310, 347 and 410, 254 SMO (1.4547), 904L (1.4539), duplex 2205 (1.4462), super duplex 2507 (1.4410), alloy steel F1–F91, Monel 400/K500, Inconel 600/625/825, Hastelloy C276/C22, titanium Gr. 2/5, copper nickel 90/10 and 70/30, and bimetal/clad — all with EN 10204 3.1 certificates.

It rises with size — the chart's bolting columns give the exact count and metric thread per DN: a DN 10 takes 4 × M12, a DN 50 takes 4 × M16, a DN 250 takes 12 × M30 and a DN 600 takes 20 × M45. Bolt holes (column L) and the bolt circle (column K) are also tabulated, so gasket and fastener take-offs can be made straight from this page.

EN 1514-1 sheet or spiral wound gaskets sized for PN 40; spiral wound preferred on steam and cycling duty. Always match the gasket to the facing form and PN class of both flanges.

The tapered hub and full-penetration butt weld make the joint as strong and fatigue-resistant as the pipe itself, the weld is easy to examine by radiography or UT, and the matched bore eliminates turbulence and crevice corrosion at the joint. Cheaper constructions have their place in undemanding services, but Type 11 is the engineering choice for process lines, temperature cycling and critical media.

When the line's design pressure (at design temperature, for your material group) exceeds the PN 40 rating of roughly 40 bar — remembering the strong temperature derating: a 35-bar steam line at 400 °C may already need PN 63 or PN 100. Surge and test pressures should be included in the check. See the PN 63 and PN 100 Type 11 charts linked on this page.

Every batch is dimensionally inspected against EN 1092-1, marked with size, PN class, material grade and heat number, and supplied with EN 10204 3.1 mill test certificates. PMI verification, ultrasonic and magnetic-particle examination, impact testing for low-temperature grades, NACE MR0175 compliance and third-party witness inspection by LR, BV, DNV, SGS, TÜV or IBR are available on request.

Yes. Besides standard EN 1092-1 dimensions we machine special bores, extended hubs and long weld neck versions, special facings and drilling, and flanges to customer drawings — including sizes outside the standard series as special forgings, quoted case-by-case. Send the drawing or datasheet and we will quote to it.

Refineries and petrochemical plants, power stations, chemical and fertiliser plants, gas processing, thermal-oil system builders, and any European-specification project in the 25–40 bar band. Because PN 40 doubles as the small-bore reference series, virtually every EN-spec project orders from this chart.

Size (DN) and quantity, standard and type (EN 1092-1 Type 11), PN class, facing form, pipe wall thickness or bore, material grade, any impact-test or NACE requirement, and the certification and inspection you need. Tesco Steel & Engineering is an ISO 9001:2015 certified flange manufacturer and exporter in Mumbai, India, shipping worldwide with sea-worthy packing.