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An FF (Full Face) gasket is a flat gasket that extends to the outer edge of the flange and includes the holes needed for the bolts or studs to pass through. Its geometry makes it easy to distinguish from an RF or IBC gasket, which is annular and sits inside the bolt circle.
This page focuses on the dimensional identification of FF gaskets for flanges designated by PN and on the standards that define their dimensions. For materials, applications and other types of gasket, see our flange gaskets page.
FF stands for Full Face: the gasket covers the face of the flange up to its outside diameter and has the holes required for the fasteners. The EN 1514-1 standard uses precisely the designation Type FF for this type of gasket.
It is defined by several dimensions directly related to the geometry of the flange:
On a standard flange, these dimensions depend on the combination of DN and PN.
The DN (nominal diameter) identifies the size of the connection and the PN (nominal pressure) the pressure rating of the flange. Specifying only the DN – for example, DN100 – may not be enough: the geometry can vary depending on the PN.
As a minimum, you should have:
DN + PN + type FF
If the flange or gasket standard is also known, identification is even more precise.
EN 1514-1 sets out dimensions for non-metallic flat gaskets, with or without inserts, intended for flanges designated by PN. The current edition, EN 1514-1:2024, covers different gasket types: FF (Full Face), IBC (Inside Bolt Circle), TG (Tongue and Groove) and SR (Spigot and Recess).
For a type FF gasket, the standard relates the DN and PN of the installation to the gasket dimensions. It is used together with the EN 1092 series of European flanges, with applications up to PN63 and sizes up to DN4000.
Need an FF gasket but unsure of the dimensions?
Send us the DN, the PN or a drawing and we will tell you which gasket you need.
In installations, drawings and technical documentation that have been in service for years, it is still common to find historical DIN references. It is important to distinguish between the standard that defines the flange and the one that sets out the gasket dimensions: for non-metallic flat gaskets for PN flanges, the current European reference is EN 1514-1.
If only an old DIN reference is available, you should check which element it refers to and confirm the DN and PN before defining the gasket dimensions.
If the part or the flange is available but the standard is not, the six dimensions above are measured: inside and outside diameter, number and diameter of bolt holes, PCD (distance between bolt hole centres) and thickness. With these, and with the DN and PN if known, it is possible to check whether the geometry corresponds to a standard size or a different configuration.
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An FF gasket extends to the outer edge of the flange and includes the bolt holes. An RF gasket, usually used as an annular gasket, sits inside the bolt circle and has no bolt holes. That is why the dimensions that define each one are different and their references must not be used interchangeably.
For annular gaskets traditionally used to DIN, see our RF gasket for raised face flanges (DIN 2690) page.
Flange DN.
PN.
Gasket type FF.
Standard, if known.
Required material.
Thickness.
Quantity.If the standard has not been identified, you can provide a drawing or the main dimensions: inside diameter, outside diameter, number and diameter of bolt holes and PCD. To choose the material according to the fluid, pressure or temperature, see our flange gaskets page.
Materials, applications and manufacture of DIN/EN and ASME/ANSI flange gaskets.
Annular gasket without bolt holes: dimensions, DIN 2690, EN 1514-1 type IBC and how to identify it.
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