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July/August 2011

Covering a Broad Scope

Form and Style Provides Guidance in Writing Specifications

Given the broad scope of ASTM International standards, it is practically impossible to list all of the subjects covered in ASTM’s specifications. However, Part B of Form and Style for ASTM Standards does provide a great deal of general guidance to committees involved in writing specifications.

Form and Style defines a specification as “an explicit set of requirements to be satisfied by a material, product, system or service.” Examples include, but are not limited to, requirements for physical, mechanical or chemical properties, and safety, quality or performance criteria. Specifications identify the test methods used to determine whether each of the requirements is satisfied.

Section B1, Functions, notes that specifications can serve any combination of the following three functions:

  • Purchasing — Sufficient requirements should be included so that all batches, lots or deliveries that conform to the spec will be satisfactory to the purchaser.
  • Standardization — A byproduct of most specifications, standardization involves a deliberate and possibly arbitrary choice of a limited number from the multiplicity of qualities, sizes, compositions, etc., that may be available.
  • Providing Technical Data — While all specifications contain technical information, in some cases more information is required than that provided for purchase or standardization. This extra information can be included as either requirements or as appendixes.

Even if a specification serves all three of these functions, it is still helpful when creating a draft to keep each of the functions in mind, so that the primary purpose of the specification does not get confused.

Form and Style also notes, in B1.2, Open-End Agreements, that no statements shall be permitted in specifications that “allow agreement between purchaser and supplier that do not meet the minimum requirements of the specification by such means as omitting tests that are a part of the specification, substituting or modifying a test method, or by changing the specification limits to be less restrictive.”

Title, designation, scope and keywords are all mandatory sections of an ASTM specification. The scope should include information relating to the purpose of the specification, such as the materials, products, systems or services to which the specification applies and any known limitations. The scope should also provide information about systems of units used and any caveats required by ASTM.

A classification section is useful in a specification when more than one material, product or system is being specified and needs to be separated within the standard. According to Section B8 of Form and Style, elements that need to be separated should be done in the following precedence:

Type, identified by Roman numerals. This first subdivision shall be based on some major property, composition or application of the item;

Grade, identified by Arabic numbers and based on some pertinent property or properties;

Class, identified by capital letters. Class would only be used if the items were not suitably separated by type and grade.

More information on the form of ASTM specifications can be found in Section B of Form and Style for ASTM Standards.