EN 1092-1 Type 11 PN 16 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 16. 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 16 is the most widely specified class in European piping, covering sizes from DN 10 up to DN 2000, with DN 10–40 sharing the PN 40 dimensions.

PN stands for “Pression Nominale” — the nominal pressure class. A PN 16 flange is rated for a maximum working pressure of about 16 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 16 is the default class of European piping specifications: municipal and industrial water lines, HVAC and district heating, compressed air, cooling circuits, general chemical and food-processing duty, and power-station auxiliaries. It carries the great majority of everyday pressures while staying lighter and cheaper than PN 25 or PN 40, which is why it is the most commonly stocked class from DN 50 to DN 2000.

EN 1092-1 gives PN 16 flanges in DN 10 through DN 40 the same dimensions as PN 40 — that is why the first six rows of the chart on this page refer to the PN 40 chart. Because the dimensions are identical, small-bore PN 16 is normally supplied and stocked as PN 40, and the dedicated PN 16 dimension series begins at DN 50.

DN 65 PN 16 is the best-known incompatibility between old DIN and current EN flanges: EN 1092-1 specifies 8 × M16 bolts, while older DIN-series flanges were drilled 4 × M16. The two patterns do not mate, which is why the bolting cell for DN 65 in our chart carries a footnote marker. Always confirm the drilling required when ordering DN 65 or matching existing equipment.

Both are butt-welding neck flanges, but they belong to different systems: EN 1092-1 is metric, sized in DN with PN pressure classes, and its bolt circles, bolt sizes and facings (Form A, B1, B2, etc.) differ from the imperial ASME B16.5 system with its NPS sizes and Class 150–2500 ratings. PN 16 is broadly comparable in duty to ASME Class 150, but the two are not interchangeable — an EN flange will not bolt to an ASME flange of the same nominal size.

The PN 16 chart on this page runs from DN 10 to DN 2000. DN 10–40 use the PN 40 dimensions; the dedicated PN 16 series runs from DN 50 upward. Above DN 600 the standard switches to its large-diameter design series — the flanges become relatively thinner with more bolts — which is also why the weight column steps down between DN 600 and DN 700.

From the weight columns in our chart: a DN 100 Type 11 flange weighs about 4.9 kg (11 lbs), a DN 300 about 23 kg (52 lbs), a DN 600 about 121 kg (268 lbs) and a DN 1000 about 178 kg (393 lbs). These are approximate carbon-steel weights calculated from the standard dimensions — actual weight varies with the bore and material.

EN 1092-1 defines facing forms by letter: Form A is a flat face, Form B1 the standard raised face with a normal serrated finish, Form B2 a raised face with a smooth finish, and Forms C–F cover tongue, groove, spigot and recess joints. Form B1 raised face is the default for PN 16 process work; Form A flat face is used against cast-iron or lined equipment. State the form required 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. The B1–B3 bore columns apply to the plate and loose flange types.

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 50 takes 4 × M16, a DN 100 takes 8 × M16, a DN 200 takes 12 × M20, a DN 500 takes 20 × M24, and a DN 2000 takes 48 × M56. Note the DN 65 footnote: EN specifies 8 × M16 where old DIN flanges used 4. Bolt holes (column L) and the bolt circle (column K) are also tabulated.

For Form B1 raised-face PN 16 flanges, non-metallic sheet gaskets to EN 1514-1 or spiral wound gaskets sized for PN 16 are standard, chosen by service temperature and medium. For Form A flat-face joints a full-face gasket is used, drilled to the same bolt pattern. 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, and the matched bore eliminates turbulence and crevice corrosion at the joint. Plate (Type 01) and hubbed slip-on (Type 12) flanges are cheaper for undemanding services, but Type 11 is the engineering choice for process lines, temperature cycling and critical media at PN 16 pressures.

When the line's design pressure (at design temperature, for your material group) exceeds the PN 16 rating of roughly 16 bar. Water hammer, surge allowances and test pressures should be included in that check. PN 25 and PN 40 share the same DN system with progressively heavier flanges and larger bolting — see our PN 25 and PN 40 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. Standard machined flanges are produced across the DN range, and large diameters — DN 700 up to DN 2000 — are made as forged rings or fabricated-and-machined flanges to the same standard. Special bores, non-standard drilling (including 4-hole DN 65 to match old DIN equipment), tongue/groove and recess facings, and flanges to customer drawings are regular work.

Size (DN) and quantity, standard and type (EN 1092-1 Type 11), PN class, facing form (A, B1, B2…), pipe wall thickness or bore, material grade, any impact-test or NACE requirement, and the certification and inspection you need — plus the DN 65 drilling pattern if applicable. Tesco Steel & Engineering is an ISO 9001:2015 certified flange manufacturer and exporter in Mumbai, India, shipping worldwide with sea-worthy packing.