PN6 Flange Dimensions (EN 1092-1 Type 11, DN10 to DN350)

PN6 flange dimensions to EN 1092-1: flange outside diameter D, bolt-circle diameter K, bolt-hole size, number of bolts, bolt size and flange thickness for Type 11 weld-neck flanges from DN10 through DN350. Includes DN50 (140 mm OD, 4 x M12), DN100 (170 mm bolt circle, 4 x M16) and DN150 (8 x M16). The lightest common low-pressure (6 bar) rating; smaller than PN10/PN16 and uses M10 bolts up to DN25. Values cross-checked across two independent reference tables.

PN6 flange dimensions (EN 1092-1 Type 11, DN10 to DN350)

PN6 is the EN 1092-1 pressure rating for a nominal 6 bar flange and the lightest common rating for low-pressure water, ventilation, gravity drainage and general low-duty service. The PN number fixes the bolt pattern, so a PN6 DN100 flange from any maker shares the same 210 mm outside diameter, 170 mm bolt circle and four M16 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 two 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: 11 mm holes take M10, 14 mm M12, 18 mm M16 and 22 mm M20. PN6 uses the lighter M10 bolt from DN10 to DN25 where the heavier PN10 and PN16 ratings already use M12, which is one of the ways a PN6 flange is told apart from a PN10 or PN16 flange of the same DN.

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 — the flange disc thickness, excluding the raised face and the weld-neck hub (the EN 1092-1 b dimension).

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 PN6 flange will not mate to a PN10, PN16 or an ASME Class flange of the same DN even though the bore is the same — the bolt circle, hole size and bolt thread differ. PN6 carries a smaller flange outside diameter and bolt circle than PN10 or PN16 at the same DN and uses a lighter bolt (M10 versus M12) up to DN25, so the two ratings do not interchange. EN 1092-1 also defines the facing (Type B1 raised face is the common PN6 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 PN6 flanges to EN 1092-1 share the same D, K, bolt hole, bolt count and bolt size, while the disc thickness varies with the flange type.

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 PN6 EN 1092-1 revision and the specific component data sheets before manufacture or procurement. All trademarks are the property of their respective owners.