ASTM D2000 Callout Decoder
How to read, decode, and specify an elastomer material callout — no guesswork, no spec sheet hunting.
How to read, decode, and specify an elastomer material callout — no guesswork, no spec sheet hunting.
M 2 BC 507 B14 | M 2 HK 714 A17 B17 EF31 | 2 CE 614 A15 B14 C12Determined by oven aging per ASTM D573 at the listed temperature for 70 hours — measures changes in tensile and elongation. Not the same as continuous field service temperature.
| Type | Test Temp | Typical Materials | Notes |
|---|---|---|---|
| A | 70°C (158°F) | Natural Rubber (NR), Reclaim, SBR | General-purpose, low-cost. No oil resistance. |
| B | 100°C (212°F) | NBR (Buna-N), SBR, Butyl (IIR) | Workhorse for petroleum hydraulics and pneumatics. |
| C | 125°C (257°F) | EPDM, Neoprene (CR), Butyl (IIR) | EPDM for water/steam; CR for moderate ozone/weather. |
| D | 150°C (302°F) | FKM (standard), Polyacrylate (ACM), HNBR, ECO | Entry-level FKM; ACM for automotive powertrain fluids. |
| E | 175°C (347°F) | FKM, Silicone (VMQ), Polyacrylate (ACM), AEM | Standard FKM (65% fluorine) is the most common choice. |
| F | 200°C (392°F) | FKM (high-fluorine), Fluorosilicone (FVMQ), Silicone | Silicone peaks here. FKM with 66–67% fluorine. |
| G | 225°C (437°F) | High-fluorine FKM (Viton GF, GBL-600S), Specialty Silicone | Requires carefully compounded FKM or specialty silicone. |
| H | 250°C (482°F) | High-fluorine FKM (Viton GF-S, GBL-S) — see HK note | Achievable with regular high-fluorine FKM. Not FFKM. |
| ⚠ FFKM (Kalrez®, Chemraz®, Simriz®) exceeds the D2000 classification matrix and is specified separately — not via a D2000 callout. | |||
Field note: HK (Type H + Class K) is a well-established FKM designation per ASTM D2000 Table X1.1 — achievable with high-fluorine FKM grades. Do not confuse with FFKM.
Volume swell in ASTM Reference Oil No. 3 at 100°C for 70 hours. Tighter class = more fluorine required = less swell in petroleum-based oils.
| Class | Max Swell in ASTM #3 Oil | Practical Meaning |
|---|---|---|
| A | No requirement | Oil resistance not tested — for non-oil service (water, steam, air) |
| B | ≤ 140% | Very high swell tolerated — NR, SBR |
| C | ≤ 120% | Low oil resistance — SBR, EPDM |
| D | ≤ 100% | Moderate — standard NBR grades |
| E | ≤ 80% | Better NBR or neoprene |
| F | ≤ 60% | High-quality NBR or ACM |
| G | ≤ 40% | High-performance NBR |
| H | ≤ 30% | HNBR or low-fluorine FKM |
| J | ≤ 20% | Standard FKM (Viton A/B) |
| K | ≤ 10% | High-fluorine FKM only — HK combination = FKM per ASTM Table X1.1 |
ASTM D2000 Table X1.1 maps specific Type+Class pairs to material families. The same material can appear at multiple levels depending on formulation.
| Type+Class | Material | Typical Use |
|---|---|---|
| AA | Natural Rubber (NR) | Vibration isolation, non-oil contact |
| BA, BC | NBR (Buna-N) | Petroleum hydraulics, general industrial |
| BG | NBR, Urethane | Higher oil resistance, mobile hydraulics |
| CA, CE | EPDM | Water, steam, brake fluids, outdoor weathering |
| CH | Neoprene (CR) | Refrigerants, moderate oils, ozone resistance |
| DA, DE | EPDM (heat-stabilized) | Automotive coolant, hot water systems |
| DF, DH | FKM (standard), HNBR | Engine oils, fuel injection at 150°C |
| EE, EF | Polyacrylate (ACM), AEM | Automotive powertrain, ATF fluids |
| EJ, EK | FKM (Viton A/B) | Petroleum oils and fuels at 175°C |
| FC, FE | Silicone (VMQ) | High-temp static seals, food-grade, −55°C to 200°C |
| GE, GF | Fluorosilicone (FVMQ) | Fuel + wide temp range −50°C to 200°C (aerospace) |
| FK, GK | FKM (high-fluorine) | Aggressive fuels, oils, chemicals at 200–225°C |
| HK | High-fluorine FKM (Viton GF, GBL-S series) | Extreme temp + oil: turbo systems, downhole, chemical process |
| Grade | Scope |
|---|---|
| 1 | Basic — Type, Class, hardness, tensile, elongation only. Suffix requirements still apply if listed. |
| 2 | Standard — adds specific testing per all suffix codes. Most industrial specs use Grade 2. |
| 3 | Extended — full qualification with higher-frequency retesting and tighter process controls. Safety-critical / aerospace. |
Each suffix = letter (which test) + 2 digits (test conditions: method + temperature). Multiple suffixes can be stacked. A callout without suffixes only guarantees the base Type/Class properties.
After oven aging at the specified temperature for 70 hours, re-measures hardness (±8 Shore A max change), tensile (−40% max), elongation (−40% max). Limits vary by condition code.
Why it matters: A material that passes the Type heat aging test can still harden or crack in service — Suffix A with a realistic temperature catches this.
Sample compressed 25% for the test duration. After release: measures permanent deformation as % of original deflection. Max ≤ 25% for most conditions (≤ 30% at high temps).
Why it matters: The single most predictive test for seal longevity in the field. A material can pass every other test and still leak due to compression set. Always specify Suffix B at or above your actual service temperature for static face seals, valve seats, and long-dwell applications.
Static exposure to ozone at defined concentration and elongation for 96 hours. Pass/fail on surface cracking. Critical for outdoor, under-hood, and HVAC applications where NBR or NR would degrade.
Measures bond strength (N/mm) of rubber-to-metal or rubber-to-plastic. Used on bonded seals, rubber-metal assemblies, and bushings. Condition digits select substrate type and test method.
The Class tests ASTM #3 oil. Suffix E tests immersion in a different fluid. A second letter identifies the fluid; the 2 digits define volume/hardness change limits and test duration.
The 2 digits after the fluid letter define max volume change acceptance limits per ASTM D2000 tables.
Tests that the material does not crack or become inflexible below the stated temperature. The condition number directly encodes the negative test temperature in °C. Critical for outdoor, cold-climate, refrigeration, and arctic/aerospace applications.
Minimum tear strength in kN/m. Important for wiper seals, energized lip seals, and any application with mechanical contact or risk of nick propagation. Condition digits set the minimum tear strength value.
Repeated bending cycles — inspected for crack initiation. Used on dynamic seals, bellows, boots, and hose assemblies that flex in service. Condition digits define number of cycles and bend radius.
Peel strength when rubber is bonded to fabric or a flexible backing. Used on fabric-reinforced diaphragms and belting assemblies.
Anything not covered by the standard suffix letters. Z1, Z2, Z3, etc. are sequentially assigned. The complete test requirement for each Z code must be fully documented on the drawing or PO. No standard definition exists — without documentation, a Z code is unverifiable and untestable.
| Property | With M prefix | Without M prefix |
|---|---|---|
| Tensile strength | MPa | psi × 100 (e.g., "14" = 1,400 psi ≈ 9.6 MPa) |
| Temperature | °C | °F |
| Volume loss (abrasion) | mm³ | in³ |
| Callout | Material | Service | Not suitable for |
|---|---|---|---|
| M 2 BC 507 B14 | NBR 50 Shore A | Petroleum hydraulics & lubricants to 100°C; pneumatics | Steam, hot water, ketones, brake fluid, ozone |
| M 2 BC 714 B14 C12 | NBR 70 Shore A (ozone-resistant) | Hydraulics + outdoor exposure | Same fluid limits as BC above |
| M 2 CE 614 A15 B14 | EPDM 60 Shore A | Steam, hot water, phosphate-ester hydraulics, brake fluid, outdoor | Petroleum oils and fuels — swells severely |
| M 2 DF 710 A16 B16 EF31 | FKM (Viton) 70 Shore A | Petroleum oils, fuels, aggressive chemicals to 150°C | Ketones, amines, steam, low-temp below −20°C |
| M 2 EK 714 A17 B17 EF31 | FKM 70 Shore A (higher fluorine) | Same + 175°C continuous + aggressive fuels | Ketones, MEK, steam |
| M 2 FC 514 A17 B17 F55 | Silicone (VMQ) 50 Shore A | High-temp static seals −55°C to 200°C, food-contact, dry heat | Dynamic seals (poor wear), petroleum oils, steam |
| M 2 GF 514 A17 B17 F40 | Fluorosilicone (FVMQ) | Fuel + wide temp range −50°C to 200°C, aerospace | Aromatic fuels >30%, ketones, acids, steam |
| M 2 HK 714 A17 B17 EF31 | High-fluorine FKM (Viton GF, GBL-S) | Extreme temp + oil + fuel: turbocharger seals, chemical process, downhole | Ketones, low-temp below −15°C without F suffix |
| Step | Question | Sets |
|---|---|---|
| 1 | Metric or imperial drawings? | M prefix (or no prefix) |
| 2 | Full qualification or baseline only? | Grade (1 = basic, 2 = standard, 3 = extended) |
| 3 | What is the maximum continuous service temperature? | Type letter (A–H) |
| 4 | What fluid contacts the seal? What swell is acceptable? | Class letter (A–K) |
| 5 | What hardness is needed? What minimum tensile? | 3-digit mechanical code |
| 6 | What additional tests are required? (aging, compression set, low-temp, fluid resistance) | Suffix codes with condition numbers |
| 7 | Any application-specific requirements outside the standard? | Z codes — document fully on drawing |