O-Ring Material Selection Guide
O-Ring compound selection guide with temperature ranges, shelf life, stocked inch and metric sizes, and where each compound belongs.
The compound is the single most important choice you make when specifying an O-Ring. It decides what temperatures the seal survives, what fluids it can touch, and how long it lasts. Use the guide below to shortlist a compound, then open its detailed page (click the compound name, or use the Compounds & Certs menu) or confirm it against your fluid on the Chemical Compatibility page. Need documentation or a spec callout? See Standards & Certifications.
Compound selection guide
| Compound | Temperature Range | Shelf Life (ARP5316) | Shop AS568 Inch | Shop Metric | Best For | Avoid With |
|---|---|---|---|---|---|---|
| Buna-N (NBR) | -40°F to +250°F (-40°C to +121°C) | 15 years | 50 Duro 70 Duro 90 Duro | 70 Duro 90 Duro | Oils, fuels, hydraulics, general purpose | Ozone, UV, ketones, esters, brake fluid |
| HNBR (HSN) | -40°F to +300°F (-40°C to +149°C) | 15 years | 70 Duro 90 Duro | 70 Duro | A/C refrigerants (R134a), automotive, sour gas | Ketones, esters, chlorinated solvents |
| EPDM | -65°F to +300°F (-54°C to +149°C) | Unlimited | 70 Duro FDA 70 Duro FDA/NSF-61 80 Duro E454 | 70 Duro | Water, steam, brake fluid, outdoor use | Petroleum oils, fuels, greases |
| Viton® (FKM) | -20°F to +400°F (-29°C to +204°C) | Unlimited | 50 Duro 75 Duro 90 Duro | 75/80 Duro 90 Duro | High heat, fuels, chemicals, vacuum | Ketones, esters, amines, hot water/steam |
| Viton® Extreme ETP | -8°F to +482°F (-22°C to +250°C) | Unlimited | 75 Duro | 75 Duro | Aggressive chemicals, FFKM alternative | Very few, broad resistance |
| Silicone (VMQ) | -75°F to +400°F (-59°C to +204°C) | Unlimited | 50 Duro 70 Duro FDA | 70 Duro | Food, medical, extreme temps (static seals) | Dynamic use, fuels, steam |
| Fluorosilicone (FVMQ) | -76°F to +392°F (-60°C to +200°C) | Unlimited | 70 Duro M25988/1 75 Duro | Contact us | Aerospace and automotive fuel systems | Dynamic wear, high pressure |
| Neoprene (CR) | -40°F to +225°F (-40°C to +107°C) | 15 years | 70 Duro | Contact us | Refrigerants, ammonia, Freon® | Strong acids, aromatics, esters |
| Aflas® (FEPM) | -25°F to +450°F (-32°C to +232°C) | Unlimited | All Aflas® | Contact us | Oil field, sour gas, steam, amines | Aromatic fuels, low temperatures |
| FFKM (Simriz®) | Up to +617°F (+325°C) by compound | Unlimited | All Simriz® FFKM | All Metric FFKM | Extreme chemical and heat service | Cost; molten alkali metals |
| PTFE (Teflon®) | -100°F to +500°F (-73°C to +260°C) | Unlimited | All PTFE | All Metric PTFE | Nearly universal chemical resistance | No elastic memory (rigid) |
| PTFE Encapsulated | FKM core: -10°F to +300°F Silicone core: -80°F to +500°F | Unlimited | FKM Core Silicone Core | FKM Core Silicone Core | PTFE chemistry with elastomer recovery | Dynamic / reciprocating service |
| Urethane Cast (Disogrin) | -115°F to +250°F (-82°C to +121°C) | 5 years / 10 with inspection | 70 Duro 90 Duro | All Metric Urethane | High pressure hydraulics, abrasion, shock loads | Hot water/steam, acids, bases, amines |
| Urethane EU (Millable) | -30°F to +180°F (-34°C to +82°C) | 5 years | 70 Duro 90 Duro | All Metric Urethane | Air guns, paintball markers, pneumatics | Hot water/steam, acids, bases, solvents |
| Butyl (IIR) | -75°F to +250°F (-59°C to +121°C) | 15 years | All Butyl | Contact us | Vacuum service, gas sealing, brake fluid | Petroleum oils, fuels, aromatics |
Temperature ranges are for standard compounds in typical service. Specialty grades within a family can run colder or hotter. When your application sits near the edge of a range, contact us and we’ll pull the compound datasheet for you.
Compound selection depends on temperature, pressure, and the specific media in your application. Once you’ve shortlisted on temperature, confirm the compound against your fluid on the Chemical Compatibility page, media is where most seal choices are won or lost.
