PN40 Flange Dimensions (EN 1092-1 Type 11, DN10 to DN350)

PN40 flange dimensions to EN 1092-1: flange outside diameter D, bolt-circle diameter K, bolt-hole size, number of bolts and bolt size for Type 11 weld-neck flanges from DN10 through DN350. Includes DN50 (165 mm OD, 4 x M16), DN100 (190 mm bolt circle, 8 x M20) and DN150 (8 x M24). The higher-pressure companion to the PN16 reference. Values cross-checked across three independent reference tables.

PN40 flange dimensions (EN 1092-1 Type 11, DN10 to DN350)

PN40 is the EN 1092-1 pressure rating for a nominal 40 bar flange and a common rating for higher-pressure water, steam and process service. The PN number fixes the bolt pattern, so a PN40 DN100 flange from any maker shares the same 235 mm outside diameter, 190 mm bolt circle and eight M20 bolts. The values below are the EN 1092-1 nominal dimensions for the Type 11 raised-face weld-neck flange across the common DN10 to DN350 range, cross-checked across three independent reference tables.

Bolt holes are drilled on the bolt circle K, straddling the centreline and equally spaced. The bolt size is the largest that passes the listed hole: 14 mm holes take M12, 18 mm M16, 22 mm M20, 26 mm M24, 30 mm M27, 33 mm M30 and 36 mm M33. Up to DN50 the PN40 bolt pattern matches PN16 and PN25; PN40 then diverges, stepping the bolt size up earlier (M20 at DN100, M24 at DN125) and reaching M33 at DN350.

Reading the dimensions

• D — the flange outside diameter; the overall diameter of the flange disc.
• K — the bolt-circle diameter (PCD), the circle through the bolt-hole centres. This is the figure to lay out or check drilling against and the single most important number for matching a mating flange.
• Bolt hole — the drilled hole diameter; the clearance over the bolt lets two flanges line up.
• Number of bolts — always a multiple of four and equally spaced, so the flange turns in quarter steps; both mating flanges share the same count.
• Bolt size — the metric thread of the through-bolt or stud. Use the full set.

Flange thickness is not tabled here: the published EN 1092-1 PN40 thickness columns differ between reference tables at the smaller DN, so a single thickness value cannot be given without ambiguity. Take the flange thickness for a given DN from the controlling EN 1092-1 table or the flange maker’s data sheet.

Selecting and matching

Two flanges bolt together only when the pressure rating, DN, bolt circle K and bolt pattern all agree, so confirm all four before ordering. A PN40 flange will not mate to a PN16 or an ASME Class flange of the same DN even though the bore is the same — the bolt circle, hole count and bolt size differ. Up to DN50 the PN16, PN25 and PN40 bolt patterns in EN 1092-1 share the same K and holes; from DN65 upward the higher rating diverges with a larger bolt circle and bolt size. EN 1092-1 also defines the facing (Type B1 raised face is the common PN40 facing) and the flange material group, which set the gasket and bolt grade for the temperature and pressure. The dimensions above are for the Type 11 weld-neck flange; blind, plate and slip-on PN40 flanges to EN 1092-1 share the same D, K, bolt hole, bolt count and bolt size.

Dimensions are nominal EN 1092-1 values and provided for identification and cross-reference. Confirm against the controlling standard and the specific flange maker’s current data sheet before manufacture or procurement.

Reference compiled for identification and cross-reference. Dimensions are nominal; confirm against the controlling EN 1092-1 PN40 EN 1092-1 revision and the specific component data sheets before manufacture or procurement. All trademarks are the property of their respective owners.