Gasket material guide
Choosing the right seal material for steam, pure water and process fluids
| Material | Continuous steam | Intermittent steam | Pure water ambient | Pure water hot | Process fluids ambient | Process fluids hot | Temp swings (<32°F to >212°F) |
Temp range |
|---|
Tuf-Flex® and Tuf-Steel® service life is application dependent. Buna does not pass USP Class VI or cytotoxicity testing and is not animal-derived-ingredient (ADI) free.
Tuf-Steel®
-320°F to 550°F
A 50/50 blend of virgin PTFE and passivated 316L stainless steel. The top choice where purity, chemical and heat resistance, and long service life all matter.
- Best for: SIP, WFI and steam lines, extreme temperatures
- Minimal creep and cold flow, so it stays leak free when torqued correctly
- Non-stick, ultra-low absorption, no pigment
Tuf-Flex®
-20°F to 300°F
A PTFE sealing face permanently bonded to an EPDM core. You get the purity of PTFE with the flexibility and memory of a rubber gasket.
- Best for: biopharma, ultra-pure water, WFI, demanding food and beverage
- Holds its seal through wide temperature swings
PTFE
-100°F to 500°F
Almost no extractables, low absorption and excellent resistance to process fluids. Long service life in water and continuous steam.
- Best for: chemical resistance and purity where temperatures are steady
- Watch out: can creep and leak with frequent large temperature swings. Use high-pressure clamps
- For slight misalignment, use a PTFE envelope gasket with an FKM core
Silicone (platinum cured)
-40°F to 450°F
Very flexible, even at low temperatures. Platinum curing keeps extractables low for sanitary water systems.
- Best for: sanitary water systems, misaligned fittings, wide temperature swings
- A cost-effective option when PTFE isn't practical
FKM fluoroelastomer (Viton®)
-30°F to 400°F
A good all-round elastomer with a high temperature limit. Rated good across steam, water and process fluids.
- Best for: hot process fluids and steam applications
- Watch out: not recommended for continuous SIP. Replace on a maintenance schedule
EPDM (peroxide cured)
-30°F to 300°F
An economical, widely specified elastomer for general sanitary service. Peroxide curing keeps extractables lower than sulfur curing.
- Best for: general process and water service, low-pressure steam
- Watch out: not recommended for continuous SIP. Replace on a maintenance schedule
Buna (nitrile)
-30°F to 200°F
The lowest-cost option with the narrowest temperature range. Usually the last choice for sanitary process lines.
- Do not use: with steam
- Watch out: not for strong acids or ozone. Does not meet USP Class VI
Many sanitary gaskets carry colored dots on the tab so you can tell the material at a glance once they're out of the bag.
| Material | Marking |
|---|---|
| Tuf-Steel®, Tuf-Flex®, PTFE | No dot |
| Silicone (platinum cured) | No dot |
| Silicone (white platinum) | One pink dot, if requested |
| FKM fluoroelastomer | One white dot and one yellow dot |
| PTFE envelope, FKM filler | One white dot and one yellow dot |
| EPDM (peroxide cured) | Three green dots |
| PTFE envelope, EPDM filler | Three green dots |
| EPDM (sulfur cured) | One green dot |
| Buna | One red dot |
Tell us what's running through the line, the temperature and how it's cleaned, and we'll recommend a material. Ratings above are general guidance; final suitability for your process is the user's responsibility.
Phone: 801-561-8877
Email: [email protected]
Ratings and temperature ranges courtesy of Rubber Fab Technologies Group, Hygienic Seal Material Guidelines. Tuf-Steel® and Tuf-Flex® are registered trademarks of Rubber Fab. Viton® is a registered trademark of The Chemours Company.