|by Richard Wilhelm
ASTM has a detailed form and style for its standards, and as a
standards developer, you need to be familiar with these rules.
But just how do you know whether the new standard youre writing
is a test method or a specification? Rich Wilhelm, of Editorial
Services, tells you the difference among the six types of ASTM
David Letterman has a recurring routine in which he challenges
an audience member to play the Know Your
game. The game is
simple. Letterman introduces an obscure topic, for example, Know
Your 19th Century Vice Presidents. After some banter with Dave,
the contestant is asked a question about Elbridge Gerry or some
equally obscure vice president. The contestant then answers the
question (or, more likely, reads the answer from the card Dave
helpfully provides) and wins dinner at a fine New York restaurant.
Here at ASTM, we also occasionally play the Know Your
This months topic: Know Your Types of ASTM Standards.
Lets begin by defining the term, standard. According to the
current Regulations Governing ASTM Technical Committees, a standard
is defined as a document that has been developed and established
within the consensus process of the Society and that meets the
approval requirements of ASTM procedures and regulations.
ASTM publishes six different types of standards: test method,
specification, classification, practice, guide, and terminology.
The definitions that appear in this article are taken from the
Regulations. The information in the brief discussions that follow
each definition is taken from Form and Style for ASTM Standards.
More details on each type, as well as information on use of the
Modified Numbering System, legal aspects in standards, and use
of SI units also can be found in Form and Style.
Although each type of standard is different from the other, certain
mandatory sections must be included in all types. Obviously each
standard must have a title and designation, but each must also
include a scope and keywords.
A definitive procedure that produces test result.
A test method usually includes a concise description of an orderly
procedure for determining a property or constituent of a material,
an assembly of materials or a product. All details regarding apparatus,
test specimen, procedure, and calculations needed to achieve satisfactory
precision and bias should be included in a test method. An ASTM
test method should represent a consensus as to the best currently
available test procedure for the use intended and it should be
supported by experience and adequate data obtained from cooperative
Examples of test methods include, but are not limited to: identification,
measurement, and evaluation of one or more qualities, characteristics
or properties. A precision and bias statement shall be reported
at the end of a test method. Aside from the mandatory sections
common to all standards, sections of Significance and Use, Hazards
(where applicable), Procedure, and Precision and Bias are mandatory
for test methods.
The question sometimes arises as to the difference between a test
method and a practice. The major difference is a test result.
A test method produces a test result. A practice does not.
An explicit set of requirements to be satisfied by a material,
product, system or service.
A wide variety of subjects are covered in ASTM specifications.
Examples of specifications include, but are not limited to, requirements
for: physical, mechanical, or chemical properties, and safety,
quality, or performance criteria. A specification identifies the
test methods for determining whether each of the requirements
Specifications may serve three functions: to facilitate purchasing;
to create standardization; and, to provide technical data. A specification
can serve all three functions, but it is important not to get
these functions confused when writing a standard.
A systematic arrangement or division of materials, products, systems,
or services into groups based on similar characteristics such
as origin, composition, properties, or use.
Because each ASTM committee is unique, the classifications written
by one committee might be quite different from those written by
another. The one common aspect to all ASTM classifications is
that each must have a mandatory Basis of Classification section.
This is the most important part of any classification as it sets
up categories in which groupings are made.
A definitive set of instructions for performing one or more specific
operation that does not include a test result.
As mentioned in the Test Methods section, occasionally there is
confusion about the differences between practices and test methods.
In addition, questions sometimes surface over the differences
between practices and guides, which are defined below. Generally
speaking, the difference between a practice and a guide is that
a practice underscores a general usage principle while a guide
suggests an approach. A guide connotes accepted procedures for
the performance of a given task.
Examples of practices include, but are not limited to: application,
assessment, cleaning, collection, decontamination, inspection,
installation, preparation, sampling, screening, and training.
A compendium of information or series of options that does not
recommend a specific course of action.
A guide may propose a series of options or instructions that offer
direction without recommending a definite course of action. The
purpose of this type of standard is to offer guidance based on
a consensus of viewpoints but not to establish a standard practice
to follow in all cases. A guide is intended to increase the awareness
of the user concerning available techniques in a given subject
area, while providing information from which subsequent testing
programs can be derived.
A document comprising definitions of terms; explanations of symbols,
abbreviations, or acronyms.
Of all the types of standards published by ASTM, terminology standards
are the most self-explanatory: it is simply a collection of definitions
and, occasionally, symbols, abbreviations and acronyms.
In addition to the six types of standards, ASTM also publishes
provisional standards, which are defined in the Regulations as
a document published for a limited time by the Society to meet
a demand for more rapid issuance of specific documents, such as
an emergency situation, regulatory requirements, or other special
circumstances. Provisional standards are not full consensus documents
because they require subcommittee consensus only. Section 14 of
the Regulations provides more information on provisional standards.
Now that the various types of ASTM standards have been defined
and described, you should have an easier time determining which
type of standard you want to write. Perhaps more importantly,
if youre ever an audience member on the Letterman show when Dave
wants to play Know Your Types of ASTM Standards, youll be ready.
Incidentally, Elbridge Gerry served as James Madisons vice president
from 1813 to 1814. //
Copyright 2000, ASTM