By Richard Wilhelm

Jul 26, 2016

Form and Style Describes Use of the Modified Decimal Numbering System

Properly organizing the sections of your standard is a crucial part of the standards development process. While the entire Form and Style for ASTM Standards manual is an aid in achieving this order, Part D, Use of the Modified Decimal Numbering System, specifically addresses the means by which information is organized in a standard. Following the rules of Part D will result in standards that flow well and are more easily understood by users.

According to Part D's introduction, ASTM International adopted the use of the modified decimal numbering system in 1963. Using the MDN system, each division in a standard is assigned a unique number that shows the relationship of that section to all previous sections.

Section D2 advises that standards writers should not use a combination of the MDN system and other numbering systems. For example, 8.4 would not be divided into subsections 8.4 (a) and 8.4 (b); instead these would become 8.4.1 and 8.4.2.

Each standard consists of primary sections, which may include one or more secondary sections. In turn, secondary sections may include ternary sections, which, finally, may include quaternary sections. Here is what this arrangement looks like:

1. (primary section)

1.1 (secondary section)

1.1.1 (ternary section)

1.1.1.1 (quaternary section)

Details on the assignment of numbers in the main body of the standard using the MDN system are given in D3. A preliminary section such as a foreword or introduction should not be assigned a number, so that the scope of the standard can be designated with the number "1."

Section D also explains how other parts of a standard should be numbered. These include the following: