ASTM D2000 Standards

How to Read and Interpret

The most common material classification system used in o-ring specification is the Standard Classification System for Rubber Products in Automotive Applications, also known as the ASTM D2000. Developed by the Society of Automotive Engineers (SAE), the line call-out is a simplified method of describing elastomer material. This page is your detailed guide to reading an ASTM D2000 line call-out.

Our ASTM D2000 Guide:

  • Helps in understanding the ASTM standard as it applies to o-rings and seals.
  • Effectively breaks down each segment of an ASTM D2000 call-out.
  • Includes Type and Class material designations and Requirement Suffixes
  • Can be emailed to you with a DOWNLOADABLE link!

The full ASTM D2000 Guide is continued on the remainder of the page below.

Get The ASTM D2000 Guide Emailed To You!

How to Read an ASTM D2000 Line Call-Out

Specification Revision

ASTM-D2000-99 M 2 HK 7 14 A1-10, B38, C12, EF31, EO88, F15, Z1

This indicates the revision year of D2000 to which the line call-out makes reference.

Measurement Units

ASTM D2000-99 M 2 HK 7 14 A1-10, B38, C12, EF31, EO88, F15, Z1

If an M is present, metric units will be used for tensile strength, temperature, and tear strength (MPa, °C, and kN/m respectively). If no M is present, English units will be used (psi, °F, and ppi respectively).

Grade Number

ASTM D2000-99 M 2 HK 7 14 A1-10, B38, C12, EF31, EO88, F15, Z1

This indicates the level of test requirements to which a material may be subjected. For example, Grade 1 shows that only basic properties are required, while Grades 2-9 require additional testing criteria, such as low temperature brittleness or special heat aging tests. In our example, we will be looking at a fluorocarbon material that must meet some or all Grade 2 requirements. Note that Grade Numbers may not be relevant to all material Types and Classes.

Type and Class

ASTM D2000-99 M 2 HK 7 14 A1-10, B38, C12, EF31, EO88, F15, Z1

The table, shown below, contains the most common polymers used for type and class.

Classification System D2000

SAE J200 Material Designation (Type and Class)

Test of Polymer Most Often Used
AA Natural rubber, reclaimed rubber, SBR, butyl, EP polybutadiene, polyisoprene
AK Polysulfides
BA Ethylene propylene, high temperature SBR, butyl compounds
BC Chloroprene polymers (neoprene), cm
BE Chloroprene polymers (neoprene), cm
BF NBR polymers
BG NBR polymers, urethanes
CA Ethylene propylene
CE Chlorosulfinated polyethylene (Hypalon), cm
CH NBR polymers, epichlorohydrin polymer
DA Ethylene propylene polymers
DF Polyacrylic (butyl-acrylate type)
DH Polyacrylic polymers, HNBR
FC Silicone (high strength)
FE Silicones
FK Fluorinated silicones
GE Silicones
HK Fluorinated elastomers (Viton®, Fluorel, etc.)
KK Perfluoroelastomers

For each Type and Class, ASTM D2000 includes a table giving all basic requirements, physical properties, and all suffix requirements.

Hardness (Durometer)

ASTM-D2000-99 M 2 HK 7 14 A1-10, B38, C12, EF31, EO88, F15, Z1

This number indicates durometer range in Shore A units (plus or minus 5 points). In our example, the material specified would possess a hardness of 70 ± 5 durometer.

Tensile Strength

ASTM-D2000-99 M 2 HK 7 14 A1-10, B38, C12, EF31, EO88, F15, Z1

The next two digits indicate the material’s minimum tensile strength. If measurements are in metric units, the digits show MPa. If measurements are in English units, the digits show psi and only the first two digits of that measurement are indicated. In our example (which is in metric units), the two tensile strength digits are “14” thus the minimum tensile strength required would be 14MPa. If this example were non-metric, this callout would be 20 (14 Mpa = 2031 psi).

The first six characters of a Line Call-Out give a lot of basic information about the type of elastomer required and its physical properties. Most specifications require more information to guarantee that the seal will meet the needs of the application.

Additional Requirement Suffixes

ASTM-D2000-99 M 2 HK 7 14 A1-10, B38, C12, EF31, EO88, F15, Z1

Suffixes appended to the Line Call-Out are letter and number combinations that indicate a material’s test and performance criteria per the Grade number indicated. In our example, A1-10 indicates a heat resistance test. B38 indicates a compression set test. C12 indicates resistance to ozone. EF31 and EO88 indicate fluid resistance criteria. F15 indicates low temperature brittleness criteria. Z1 indicates a user-defined requirement as must be specified including test criteria.

Refer to ASTM D 2000 for expanded suffix call-out details.

Suffix Letter Test Required
A Heat Resistance
B Compression Set
C Ozone or Weather Resistance
D Compression-Deflection Resistance
EA Fluid Resistance (Aqueous)
EF Fluid Resistance (Fuels)
EO Fluid Resistance (Oils and Lubricants)
F Low Temperature Resistance
G Tear Resistance
H Flex Resistance
J Abrasion Resistance
K Adhesion
M Flammability Resistance
N Impact Resistance
P Staining Resistance
R Resilience
Z Any Special Requirement (Specified in Detail)