Why Elastomer Seal Materials Determine Seal Life
A seal rarely fails because of its size. Instead, it usually fails because the material was wrong for
the job. Chemicals swell it, steam hardens it, or plasma erodes it. As a result, choosing the right elastomer seal materials is the most important step in seal design.
This guide helps engineers and procurement teams make that choice with confidence. First, we cover the core polymer families. Next, we lay out the decision criteria that matter most. Finally, we give industry-specific recommendations for pharmaceutical, food, semiconductor, oil and gas, chemical processing,
aerospace, and industrial equipment.
Throughout the guide, we link to Marco Sealing Solutions products, datasheets, and reference tools. That way, you can move from research to a quote in a few clicks.
The Core Families of Elastomer Seal Materials
Most industrial seals come from about ten polymer families. Each family has a clear sweet spot. However, individual compounds within a family can perform very differently. For that reason, always check the compound datasheet, not just the family name.
The table below summarizes typical dry-air temperature ranges from Marco’s O-Ring Material Quick Reference Guide. Actual limits depend on media, pressure, and hardware.
| Material | Typical Range (°F) | Best At | Avoid |
|---|---|---|---|
| Buna-N (NBR) | -31 to 250 (specialty -70 to 275) | Petroleum oils, fuels, water | Ketones, brake fluid, ozone, strong acids, UV exposure |
| HNBR | -30 to 325 (specialty -50 to 350) | Hot oils, sour crude, abrasion | Ketones, strong oxidizers |
| EPDM | -65 to 300 | Hot water, steam, brake fluid, ketones | Petroleum oils and fuels |
| Viton® (FKM) | -15 to 437 (specialty -54 to 437) | Fuels, oils, most acids, vacuum | Ketones, amines, Skydrol, hot water (standard grades) |
| Aflas® (FEPM) | 25 to 450 (specialty 5 to 482) | Amines, bases, steam, sour oilfield fluids | Ketones, Skydrol, low-molecular esters |
| Silicone (VMQ) | -65 to 400 (specialty -100 to 500) | Dry heat, wide temperature swings, non-toxic uses | Abrasion, ketones, acids, silicone oils |
| Fluorosilicone (FVMQ) | -80 to 350 | Jet fuel and low temperature | Abrasion, hydraulic fluids, brake fluid |
| Neoprene (CR) | -35 to 250 | Refrigerants, ammonia | Gasoline, ketones |
| Polyurethane | -30 to 180 (specialty -65 to 300) | Wear and extrusion in hydraulics | Water, acids, hot service |
| FFKM perfluoroelastomer | 5 to 550 (specialty -50 to 650) | Nearly universal chemical resistance, highest heat | Molten alkali metals, some fluorinated fluids |
In addition, two plastic options fill important gaps.
- FEP-encapsulated O-rings: a PTFE-family jacket over an elastomer core, giving broad chemical resistance at lower cost than FFKM. The link to the encapsulated O-rings page is unchanged.
- Spring-energized PTFE seals: a metal spring keeps the PTFE jacket loaded against the hardware, for chemicals, temperature extremes, and pressures beyond a standard elastomer. This links to Marco’s spring-energized seals page.
Where FFKM Perfluoroelastomer Fits
FFKM perfluoroelastomer is the elastomer equivalent of PTFE. It handles the widest range of chemicals and the highest temperatures of any rubber. Consequently, it is the default choice when downtime costs more than the seal.
Marco’s Markez® FFKM line offers performance similar to major brands at a lower price. For example, the general-purpose Markez Z1028 compound is rated to 610°F (321°C). Similarly, Z1400 handles long-term service up to 335°C. Marco also supplies Chemraz® and Parker branded products.
How to Choose Elastomer Seal Materials: Six Decision Criteria
Good selection starts with the service conditions, not the catalog. Before you compare O-ring materials, answer these six questions.
- What media will the seal touch? List every fluid, steam, gas, cleaning agent, and sterilant. Then check each one in Marco’s O-Ring Chemical Compatibility Guide.
- What is the temperature range? Include peaks, cold starts, and thermal cycling. Also remember that published limits assume dry air.
- What pressure or vacuum will it see? High pressure drives extrusion. By contrast, vacuum service raises permeation and outgassing concerns. See the O-ring permeation guide.
- Is the seal static or dynamic? Dynamic seals need wear resistance. For example, FFKM lists dynamic service as a limitation.
- Which certifications apply? FDA, USP Class VI, NSF, 3-A, MIL-SPEC, and NORSOK M-710 each narrow the field quickly.
- What does failure cost? If one leak halts a fab or a well, a premium compound is often the cheaper choice.
In addition, gland design matters as much as chemistry. A good compound in a poor groove still fails. Therefore, pair your material choice with the O-Ring Groove Design Guide. If a seal has already failed, the O-Ring Failure Analysis guide helps you find the root cause.
Quick Reference: Elastomer Seal Materials by Application
| Application | First Choice | Alternatives | Marco Compounds to Review |
|---|---|---|---|
| Pharmaceutical processing seals | EPDM | FFKM, steam-grade FKM | E1000, Z1426 |
| Steam sterilization / autoclave | Peroxide-cured EPDM | Steam-resistant FKM, FFKM | E1000, V1118, Z1352 |
| Medical devices (FDA, USP Class VI) | Platinum-cured silicone | FFKM | S1037, Z1318 |
| Direct food contact | FDA EPDM or silicone | FDA NBR, FKM, FFKM | B1002, Z1416, E1000, S1000, V1006 |
| CVD and plasma chambers | High-purity FFKM | Blue FVMQ for ash | Z1400, Z1403, Z1419, F1001 |
| Cleanroom and low outgassing | Non-carbon-black FFKM | White FKM, platinum silicone | Z1218, Z1407, Z1419, Z1403 |
| Wafer transfer, low stickiness | Low-sticking FFKM | Coated seals, PU pads | Z1400, P1000 |
| Subsea oil and gas equipment | Low-temp AED FKM | HNBR, low-temp FFKM | V1160, R1008, Z1322 |
| Explosive decompression / high pressure | 90–95 durometer AED FKM | FFKM, HNBR + backup rings | V1044, Z1412, E1141, V1090 |
| H2S and sour gas | FFKM | Aflas, base-resistant FKM | Z1412, L1009, L1010, V1090 |
| High-temperature refinery | FFKM | Aflas, high-performance FKM | Z1028, Z1400, Z2000 |
| Aggressive solvents | FFKM | Viton ETP, spring-energized PTFE, FEP-encapsulated | Z1028, Z1352, V1020 |
| Aerospace hydraulics (MIL-H-5606) | AMS-P-83461 NBR | AMS 7276 FKM | M1000, M1001, V1002 |
| Jet fuel | Fluorosilicone (FVMQ) | AMS 7270 NBR, FKM | F1001, F1002, F1003, F1004, M1007 |
| Low-temperature aerospace | Silicone or FVMQ | ULT FKM | V1166 |
| Engine oil and industrial hydraulics | Buna-N (NBR) | HNBR, low-temp NBR | B1000, B1083, R1008 |
| Automotive fuel systems and under-hood heat | FKM | HNBR (moderate heat) | V1000 |
| Coolant, brake fluid, and outdoor exposure | EPDM | Neoprene for refrigerants | E1000 |
| High-wear hydraulic cylinders | Polyurethane | 95-durometer FKM + backup rings | P1000, PTFE |
Elastomer Materials by Industry and Application
Read on to find application-specific recommendations for your industry.
- Elastomer Seal Materials for Medical Device & Pharmaceutical Processing
- Food and Beverage: O-Ring Materials Approved for Direct Food Contact
- Plasma-Resistant Seals and Elastomer Seal Materials for Semiconductor Fabs
- Elastomer Seal Materials for Oil & Gas: Subsea, Sour Gas, and Refinery Service
- Chemical-Resistant Seals for Aggressive Solvents in Chemical Processing
- Aerospace & Defense: MIL-SPEC O-Ring Materials for Fuel, Hydraulics, and Cold
- Elastomer Seal Materials for Automotive & Industrial Equipment
