Decoding ASTM D2000 Specifications

ASTM (American Society for Testing and Materials) D2000 provides a way for buyers and suppliers to have a standard way to describe rubber. It's clear, concise, and highly descriptive explanation creates a "common language" for communication. Do you know what each section of the specification is telling you?

For our example we're going to use compound Chloroprene/Neoprene: ASTM D2000-05 M2BC 507 A14EO34

ASTM D2000-05 M2BC 507 A14O34

The beginning letters and numbers indicate the ASTM standard

ASTM D2000-05 M2BC 507 A14O34

The numbers after the standard indicate what year the standard was last revised — in this case 2005.

ASTM D2000-05 M2BC 507 A14O34

The next letter indicates the unit of measure used to report test results. The 'M' lets you know this compound uses the metric system— the International System of Units (SI). When not prefixed by the letter 'M', the compound is referring to an earlier system based on inch-pound units. The change to SI occurred in 1980.

ASTM D2000-05 M2BC 507 A14O34

The number next to the unit of measure dictates material Grade. Our example compound is a Grade 2. Designating a grade other than Grade 1 allows for the addition of suffix requirements (A14O34).

ASTM D2000-05 M2BC 507 A14O34

The 'B' is the type of material, classified by temperature resistance. ASTM D2000 requires that rubber materials meet the following requirements after 70 hours of heat aging at the type testing temperature:

ASTM D2000-05 M2BC 507 A14O34

The 'C' signifies the class of material. Class is based upon the resistance to swelling in IRM #9 oil, after 70 hours at the temperatures in the table below. A maximum of 150°C has been established, which is the test oil limit of stability.

ASTM D2000-05 M2BC 507 A14O34

Letter designations are always followed by three numbers. The first number denotes durometer hardness — in our example the durometer is 50 +/-5 in Shore A.

The last two numbers indicate the minimum tensile strength. 07 means the tensile strength must be at least 7 MPa (mega Pascals) or 1015 PSI. Reference Table 6 in ASTM D2000 guide.

To convert a MPa to PSI use the following formula: MPa x 145.03773800722

ASTM D2000-05 M2BC 507 A14O34

The last section of the description is called suffix requirements. Suffix requirements are only specified as needed to define qualities necessary to meet service requirements. Not all suffix values available for a given material need to be specified.

In our example the suffix values are A14 and O34. The letter indicates a required test as specified in the following table as well as in Table 3 in the ASTM D2000 guide. The first suffix number indicates the test method as defined in Table 5 of the guide, and the second suffix number indicates the test temperature as defined in Table 4 of the guide.

Suffixes starting with Z dictate a special requirement. This requirement is not covered by tests in the tables of ASTM D2000 as they are user defined and should always be clearly specified in advance.