EN 1092-1 Type 11 PN 6 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 6. 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 6 is rated for roughly 6 bar at room temperature, and the chart on this page covers DN 10 to DN 3600.

PN stands for “Pression Nominale” — the nominal pressure class. A PN 6 flange is rated for a maximum working pressure of about 6 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 6 is chosen for the gentle end of plant duty: low-pressure and gravity water lines, drainage and sewage, air, flue-gas and ducting systems, HVAC and condensate headers, and very large low-head pipelines. Because pressures are low, the class stays economical at very large diameters — the chart runs to DN 3600 — where a higher PN rating would simply add dead weight.

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/C3, lengths H2 and H3, neck diameter N1, radius R and neck wall S.

PN 6 sits below ASME Class 150 in duty (Class 150 allows roughly 20 bar cold for A105, PN 6 roughly 6 bar). The systems are dimensionally unrelated: EN 1092-1 uses DN sizes, metric bolting and its own facings, ASME B16.5 uses NPS sizes and imperial bolting — the two never bolt together at the same nominal size.

The PN 6 chart on this page runs from DN 10 to DN 3600 — one of the widest spans in EN 1092-1. Small and mid sizes are machined from forgings; very large diameters are produced as forged rings or fabricated and machined to the standard, with dimensions per the chart.

From the weight columns in our chart: A DN 50 about 1.6 kg (3.5 lbs), a DN 100 about 3.7 kg (8.2 lbs), a DN 200 about 8.9 kg (20 lbs), a DN 300 about 16 kg (36 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 × M10, a DN 200 takes 8 × M16, a DN 1200 takes 32 × M30 and a DN 3600 takes 80 × M52. 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 non-metallic sheet gaskets sized for PN 6 — the low bolt loads of this class suit soft gaskets; full-face gaskets for Form A flat face. 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 6 rating of roughly 6 bar. Water hammer, surge allowances and test pressures should be included in that check. PN 10 and PN 16 share the same DN system with progressively heavier flanges — see their Type 11 charts linked on this page for direct comparison.

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.

Water and wastewater utilities, HVAC and district-heating contractors, power-station auxiliary and flue-gas systems, shipyards, and any European-specification project moving large volumes at low pressure. EPC contractors ordering to EN piping classes use PN 6 Type 11 flanges on the largest, lowest-pressure lines of the plant.

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.