AFLAS O-Rings (FEPM)
The high-performance choice for steam, sour gas, amines and caustic environments where FKM and FFKM are evaluated.
Overview
AFLAS is a tetrafluoroethylene propylene copolymer (FEPM) that occupies a unique position in the high-performance sealing market. It delivers exceptional resistance to steam, hot water, strong bases (alkalis), amines and sour gas (H2S) — media that rapidly degrade standard FKM compounds.
With a continuous operating temperature range of -5C to +230C, AFLAS is widely specified in oil and gas downhole tools, geothermal wellheads, power plant water treatment systems, and chemical processing plants handling caustic soda and amines. Its resistance to phosphate ester hydraulic fluids also makes it suitable for aerospace and industrial hydraulic systems using Skydrol.
AFLAS is not compatible with aromatic hydrocarbons, ketones or chlorinated solvents. In these environments, FKM or FFKM should be selected instead. For applications involving hot water, steam, bases and sour gas, AFLAS often provides the most cost-effective high-performance solution.
Material Properties
| Temperature Range | -5C to +230C (+23F to +446F) |
| Hardness Range | 60-90 Shore A |
| Tensile Strength | 10-18 MPa |
| Elongation at Break | 150-300% |
| Steam Resistance | Excellent (up to +200C) |
| Base Resistance | Superior vs FKM |
| Color (standard) | Black |
| Standards | ASTM D2000 CH, API 6A, NACE MR0175 |
Typical Applications
Oil & Gas
Downhole packer seals, wellhead equipment and BOP seals in sour gas and high-pH environments
Geothermal
Wellhead and valve seals exposed to high-temperature brine and steam
Power Generation
Steam turbine seals, boiler feedwater valves and water treatment system O-rings
Chemical Processing
Reactor seals, agitator seals and pump seals handling caustic soda and amines
Aerospace
Phosphate ester hydraulic fluid seals (Skydrol) and engine hot-section gaskets
Chemical Compatibility Summary
Compatible With
- - Steam and hot water
- - Strong bases and caustic soda
- - Amines and oilfield chemicals
- - Sour gas (H2S)
- - Aliphatic hydrocarbons
Incompatible With
- - Aromatic hydrocarbons
- - Ketones and chlorinated solvents
- - Strong oxidizing acids
- - Some automotive fuels (high aromatic)
- - Polar solvents
Compare Nearby Materials
Further Reading
AFLAS vs FKM
The clearest comparison for amines, steam, sour gas, and aggressive process duty.
Read articleBest Material for Oil and Gas
How AFLAS competes with HNBR, FKM, and FFKM in field applications.
Read articleKey Advantages
Exceptional Steam and Hot Water Resistance
AFLAS maintains sealing integrity in continuous steam service up to +200C, outperforming FKM and HNBR in wet heat environments.
Superior Base and Amine Resistance
Strong alkalis, caustic soda and oilfield amines that attack FKM have minimal effect on AFLAS compounds.
Sour Gas (H2S) Compatibility
NACE MR0175 compliant AFLAS grades are used extensively in sour gas wellheads and downhole tools where H2S concentrations are high.
Cost-Effective High Performance
AFLAS delivers many of the benefits of FFKM at a significantly lower cost for steam, base and amine applications.
Frequently Asked Questions - AFLAS
What is AFLAS and how is it different from FKM?
AFLAS (FEPM) is a tetrafluoroethylene propylene copolymer. It offers superior steam, base, and amine resistance compared to FKM, though it is less resistant to aromatic hydrocarbons.
Where is AFLAS commonly used?
AFLAS is specified in oil & gas downhole seals, geothermal equipment, steam boilers, and chemical plants where caustic media are present.
Can AFLAS handle sour gas (H2S)?
Yes. AFLAS exhibits excellent resistance to sour gas, oilfield amines, and high-pH environments that degrade many other elastomers.
What is the temperature range of AFLAS O-rings?
AFLAS operates from approximately -5C to +230C, with excellent long-term stability in hot water and steam up to +200C.
Is AFLas more expensive than FKM?
AFLAS is generally comparable to or slightly more expensive than standard FKM, depending on the grade and application requirements.