Navigating Flange Standards
Australia's industrial infrastructure uses a mix of local, American, and European pipe flange standards — often within the same facility. Selecting the correct flange gasket size requires identifying which standard and pressure class your flange belongs to. We manufacture to all three.
AS 2129
Australian Standard
Steel pipe flanges for water, mining, and legacy infrastructure. Pressure classes designated as Table D (lower) and Table E (higher). By far the most common standard in Australian water utilities.
ASME B16.21
American Standard
Non-metallic flat gaskets for pipe flanges. Pressure classes designated as Class 150, 300 and 600. Common on imported equipment and in oil & gas applications.
EN 1514
European Standard
Non-metallic flat gaskets for EN 1092-1 flanges. Pressure classes designated as PN 10 and PN 16. Encountered on European-manufactured equipment.
DN vs NPS — Nominal Size Designations
DN (Diametre Nominal) is the metric designation used by AS 2129 and EN 1514. NPS (Nominal Pipe Size) is the imperial designation used by ASME. Both are nominal — they don't represent the actual measured pipe diameter. For example, DN 50 and NPS 2" both refer to the same pipe size (60.3 mm OD).
All dimensions in the tables below are in millimetres (mm). ASME tables show both NPS and the DN equivalent for convenience.
Full Face vs Ring Gaskets
Every dimension table below includes both the Ring OD and the Full Face OD. The correct choice depends on your flange face type.
Full Face Gaskets
For Flat Face (FF) flanges
Extended to the outside diameter of the flange, with bolt holes punched through the gasket. These are essential for Flat Face flanges to prevent bending of brittle flange materials (such as cast iron) during bolt tightening.
Use the Full Face OD, PCD, Bolts, and Bolt Hole columns.
Ring Gaskets
For Raised Face (RF) flanges
Ring gaskets (also called IBC — Inner Bolt Circle) sit inside the ring of bolts, on the raised face. These are used on Raised Face flanges to concentrate bolt load onto a smaller sealing area, improving gasket compression and seal performance.
Use the Ring OD column. Bolt hole dimensions are not needed for ring gaskets.
Measurement Guide
Read how to measure your flange and identify whether you need a Full Face or Ring gasket.
Gasket Profile Generator
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AS 2129 — Australian Standard
AS 2129 is the dominant flange standard in Australian water utilities and mining. Table D covers lower pressures, Table E covers higher — both use the same nominal bore range. Widely used in water utilities, mining, and legacy Australian infrastructure.
Click a table card to switch. All dimensions in mm.
Source: AS 2129-2000 — Flanges for pipes, valves and fittings. Gasket IDs are nominal pipe OD + clearance. Verify against your physical flange.
ASME B16.21 — Non-Metallic Flat Gaskets
Gasket dimensions for ASME B16.5 flanges. Class 150, Class 300 and Class 600 are the primary pressure classes for flat gaskets. Sizes shown as NPS with DN equivalent in parentheses. All dimensions converted to mm.
Click a class card to switch. All dimensions in mm.
Source: ASME B16.21-2021 — Nonmetallic Flat Gaskets for Pipe Flanges. Dimensions converted from inches to mm. Gasket IDs per ASME B16.21-2021 Table 2.
EN 1514 — European Standard
EN 1514 covers gaskets for EN 1092-1 flanges — the European equivalent of the ASME B16.5 system. PN 10 and PN 16 are the two pressure-nominal ratings most commonly seen in Australian applications. Some smaller sizes share dimensions between PN classes — differences appear at larger diameters.
Click a PN card to switch. All dimensions in mm.
Source: EN 1514-1:2024 — Flanges and their joints. Dimensions of gaskets for PN-designated flanges (EN 1092-1).
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Custom & Non-Standard Gaskets
We specialise in custom-cutting non-standard gaskets for legacy, bespoke, or oversized equipment — it's what we do every day. Our CNC capability allows us to cut any size from rubber, compressed fibre, PTFE, and metallic sheet.
If your flange doesn't match any standard table, or you need a gasket for a non-standard PCD, bolt pattern, or irregular shape — send us your measurements or drawing and we'll quote it.
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Disclaimer
This resource is provided for general engineering reference only and does not constitute professional advice, specification, or guarantee of performance. Actual results depend on specific application conditions. Universal Gaskets Pty Ltd accepts no responsibility or liability for decisions made based on this information. For full terms, see our Terms & Conditions.
Standards are periodically revised, and specific equipment may deviate from generic tables. Always verify against physical flange measurements or the current published edition of the relevant standard.