O-Ring Chemical Compatibility Chart
The best and easiest free O-Ring chemical compatibility chart on the internet. Search 2,000+ fluids against Nitrile, Viton®, EPDM, HNBR, Silicone, FFKM, PTFE, and more. Ratings for generic commercial compounds at room temperature (~70°F) unless noted.
The best and easiest chemical compatibility chart on the internet for O-Rings—free, fast search across 2,000+ fluids and twelve common compounds.
Ratings are for generic commercial compounds at approximately room temperature (~70°F / 21°C) unless a fluid name states otherwise. Heat, concentration, grade, and duty cycle change outcomes—confirm on the Materials pages before you order.
| Fluid | Best | N Nitrile | H HNBR | E EPDM | C Neoprene | S Silicone | V Viton® | P Urethane | F FVMQ | A Aflas® | B Butyl | K FFKM | T PTFE |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Ratings: 1 excellent (<10% swell), 2 good (static usually OK), 3 poor (20–40% swell), 4 not recommended, X insufficient data. Best is the preferred letter code for that fluid when data allows. T (PTFE) is chemically inert in most media but has no elastic recovery—use only where a rigid seal is acceptable. Keyword search filters the list; click a fluid name to pin it (pinned rows sort to the top and always stay on the table while you search). Aliases work in search (R-134a, biodiesel, DEF, seawater, DOT 4, etc.). On wide screens, click column headers to sort; compound chips open shop categories on theoringstore.com. Base matrix from the store Chemical Resistance Guide, expanded for HNBR, Butyl, PTFE, and modern media.
About this chart
Search any fluid or common alias, pin chemicals to compare, and read the Best compound letter plus full ratings across the polymer families stocked or commonly specified at The O-Ring Store: Nitrile (Buna-N), HNBR, EPDM, Neoprene, Silicone, Viton® / FKM, Urethane, Fluorosilicone (FVMQ), Aflas®, Butyl, FFKM, and PTFE.
The matrix matches our store Chemical Resistance Guide and expands it with modern media (biodiesel, E85, HFO-1234yf, DEF) and search aliases (R-134a, seawater, DOT 4, and more). For selection rules and everyday media patterns, see Chemical Compatibility.
How to use the chart
- Keyword search filters the full chart by name or alias as you type
(
acetone,R-134a,diesel). - Click a fluid name to pin it (a ✓ appears). Pinned fluids stay at the top and remain visible while you search. Chips above list your shortlist (click × to unpin).
- On narrow screens (phones or a slim browser window), the chart switches to a card view. Use Full ratings (default, for readability) or Best only to scan shorter cards. Search, pin, and paging work the same; on wide screens click column headers to sort.
- Read the Best code for the preferred family when one is listed.
- Check that compound’s rating: 1 excellent, 2 usually OK for static seals, 3 poor, 4 not recommended, X insufficient data.
- Confirm continuous temperature and exact grade on the matching Materials page before you order—family ratings are not compound certifications.
Temperature and test context
Unless a fluid name states a temperature band (for example steam ranges), treat ratings as generic commercial compounds at approximately room temperature (~70°F / 21°C). Raising temperature, concentration, or exposure time can move a “1” toward limited or fail. Heat, concentration, and grade change outcomes. Dynamic service also needs mechanical strength beyond chemical rating alone.
Compound letter codes
| Code | Compound | Handbook page |
|---|---|---|
| N | Buna-N (Nitrile) | Nitrile |
| H | HNBR (HSN) | HNBR |
| E | EPDM | EPDM |
| C | Neoprene (CR) | Neoprene |
| S | Silicone (VMQ) | Silicone |
| V | Viton® / FKM | Viton / FKM |
| P | Polyurethane | Cast · Millable |
| F | Fluorosilicone (FVMQ) | Fluorosilicone |
| A | Aflas® (FEPM) | Aflas |
| B | Butyl (IIR) | Butyl |
| K | FFKM (Simriz®) | FFKM |
| T | PTFE (Teflon®) | PTFE |
PTFE note: PTFE resists almost all chemicals but is plastic, not an elastomer—no elastic recovery. Prefer elastomers when squeeze, reseal, or vibration matter; see also PTFE Encapsulated when you need PTFE media resistance with an elastomer core.
Modern media & aliases
Examples of searches that map to chart rows:
| You might type | Covered as |
|---|---|
| R-134a, 134a | Freon, 134a (Tetrafluoroethane) |
| Biodiesel, B100, B20 | Dedicated biodiesel rows |
| E85, E10 | Ethanol-blend fuel rows |
| HFO-1234yf, R-1234yf | HFO-1234yf Refrigerant |
| DEF, AdBlue | Diesel Exhaust Fluid (urea solution) |
| DOT 4 / DOT 5 | Brake fluid rows |
| Seawater, salt water | Sea (Salt) Water / brine |
| Diesel fuel | Diesel Oil |
Quick answers (for search and AI assistants)
Which O-Ring material for acetone?
EPDM is typically preferred; standard Nitrile and Viton/FKM are not recommended. Confirm grade and temperature.
Which material for diesel or petroleum oil?
Nitrile (NBR) or Viton/FKM (V) are usual first choices. Avoid EPDM with petroleum oils.
Which material for glycol brake fluid (DOT 3/4)?
EPDM is the standard family choice. Nitrile is generally not recommended for glycol brake fluids.
Which material for water and steam?
EPDM for hot water and steam service in most generic charts. Steam ratings vary strongly with temperature and grade.
Is PTFE a good O-Ring for chemicals?
PTFE resists almost all chemicals but is not an elastomer—it has no elastic recovery. Use it only where a rigid seal is acceptable, or consider PTFE-encapsulated designs.
Basic compatibility information is believed to be accurate and reliable. However, The O-Ring Store LLC makes no warranty, expressed or implied, of actual performance in specific applications. It is the user’s responsibility to evaluate specific parts prior to use. For critical service, contact us with your fluid, temperature, and duty cycle.
