O-ring FPM 116x4 FKM Viton

O-ring FPM 116x4 FKM Viton

O-ring FPM 116x4 FKM Viton is an elastomeric sealing ring with a nominal inside diameter of 116 mm and a cross-section of 4 mm. It is made from FKM fluoroelastomer, also referred to as FPM. This material is commonly used in sealing applications requiring resistance to many oils, fuels, lubricants and other media compatible with the specific FKM compound.

Technical data

What does O-ring size 116x4 mean?

The designation 116x4 mm defines two primary dimensions:

• 116 mm - nominal inside diameter ID
• 4 mm - cross-section CS

The 116 mm dimension does not refer to the outside diameter.

Based on nominal geometry, the approximate outside diameter is:

116 mm + 2 x 4 mm = 124 mm

For identification and ordering, the primary size remains 116x4 mm, meaning inside diameter x cross-section.

FKM, FPM and Viton - what do these terms mean?

FKM is the widely used ASTM designation for a family of fluoroelastomers, while FPM is a designation commonly encountered in DIN/ISO terminology.

Viton is a trademark for fluoroelastomer materials owned by Chemours. Therefore, not every O-ring made from FKM/FPM should automatically be described as being made from genuine Viton.

If the manufacturer does not specifically confirm Viton material, the technically precise designation is O-ring FKM/FPM 116x4 mm.

FKM/FPM material properties

FKM fluoroelastomers are widely used in sealing technology because of their resistance to many:

• mineral oils
• fuels
• lubricants and greases
• hydrocarbons
• chemical media compatible with the specific FKM compound

FKM is also commonly selected for applications requiring higher temperature capability than many standard NBR compounds.

However, there is no single universal temperature range or chemical-resistance profile applicable to every FKM O-ring. Performance depends on the specific compound, medium and operating conditions.

FKM vs NBR

FKM/FPM and NBR O-rings may have identical 116x4 mm dimensions, but this does not make them the same product.

FKM is commonly selected where chemical or thermal operating conditions exceed the capabilities of a suitable NBR compound. NBR remains widely used in many standard oil, grease and general technical sealing applications.

Material selection should therefore be based on the actual operating conditions rather than dimensions alone.

How to select an O-ring FKM 116x4

Before ordering, verify:

• inside diameter: 116 mm
• cross-section: 4 mm
• material: FKM/FPM
• required elastomer hardness
• operating medium
• operating temperature
• pressure
• groove dimensions and geometry
• static or dynamic sealing conditions

Identical 116x4 mm dimensions do not automatically make NBR, FKM, EPDM or VMQ O-rings interchangeable.

Installation

The groove and mating surfaces should be clean before installation. Avoid twisting, cutting or excessively stretching the O-ring during assembly.

Sharp edges, threads and burrs can damage the elastomer surface and may lead to premature sealing failure.

Alternative designations and search references

This specification may also be searched as:

• O-ring FPM 116x4
• O-ring FKM 116x4
• FKM O-ring 116x4 mm
• FPM O-ring 116x4 mm
• O-ring 116x4 FKM
• O-ring 116x4 FPM
• O-ring 116 x 4 FKM
• Viton O-ring 116x4

The term Viton O-ring should be used as a material identification only when genuine Viton material is confirmed.

FAQ

What are the dimensions of the O-ring FKM 116x4?

The nominal inside diameter is 116 mm and the cross-section is 4 mm.

What is the outside diameter of a 116x4 O-ring?

Based on nominal geometry, the outside diameter is approximately 124 mm.

Are FPM and FKM the same type of elastomer?

Both designations refer to fluoroelastomers. FKM is widely used in ASTM terminology, while FPM is encountered in DIN/ISO terminology.

Is FKM the same as Viton?

Not necessarily. Viton is a trademark for fluoroelastomer materials owned by Chemours, while FKM describes a family of fluoroelastomers. An FKM O-ring may be manufactured from Viton, but this must be confirmed by the manufacturer.

Can an O-ring FKM 116x4 be replaced with an NBR 116x4 O-ring?

Not automatically. Although the nominal dimensions are identical, NBR and FKM have different material properties and resistance to media and temperature.

What media are FKM O-rings used with?

FKM is commonly used with many oils, fuels, lubricants, hydrocarbons and other compatible media. Compatibility of the specific FKM compound with the actual medium should always be verified.

Do all FKM O-rings have the same temperature range?

No. Permissible operating temperature depends on the specific FKM compound, medium and operating conditions.

O-ring FPM 116x4 FKM - key information

O-ring 116x4 FKM/FPM is a fluoroelastomer sealing ring with a nominal inside diameter of 116 mm and a 4 mm cross-section. FKM is commonly used in applications involving many oils, fuels and other compatible media. Viton is a Chemours trademark and should not automatically be treated as a synonym for every FKM material.