Amendments are one of the primary means by which standards can be changed. An amendment alters or adds to the technical provisions previously agreed upon within an international standard. Like the standards’ revisions themselves, an amendment must be agreed upon through the consensus process.
A good example of this is ISO/IEC 14496-5:2001 - Information technology - Coding of audio-visual objects - Part 5: Reference software, which actually has been amended several times since its initial publication. One of these alterations was conducted through the release of ISO/IEC 14496-5/AMD1:2002 - Amendment 1: Reference software for MPEG-4. This amendment completely replaces clause 4 of the document.
Another means by which standards can be altered slightly is through a corrigendum. Corrigenda differ significantly from amendments, and the differences between the two are conveyed clearly through their definitions in the IEEE Standards Board Operations Manual. In this document, an amendment is described as:
“A document that adds to, removes from, or alters material in a portion of an existing IEEE standard and may make editorial or technical corrections to that standard.”
And a corrigendum is described as:
“A document that only corrects editorial errors, technical errors, or ambiguities in an existing IEEE standard.”
While this explicitly states that these definitions apply to IEEE standards, they are still applicable to all international standards. From this, it can be seen that a corrigendum does not add any new material, and has no effect on the scope of the document.
An example would be the corrigendum to NSF/ANSI 4-2005E, titled Editorial Corrections to NSF/ANSI 4-2005E. As implied by its name, this document only makes minor changes to the original standard, being concerned primarily with the insertion of headings.
It is also important to point out that corrigenda are not limited simply to the content of the document. For example, the corrigendum to ISO 11634:1996 - Snowboard-boots -- Interface with ski-binding marks one small alteration: a change to the title. ISO 11634/COR1:2007 retroactively changes the name of this document to “Snowboard-boots — Interface with snowboard bindings” to better match the current terminology of the industry.
Lastly, errata generally mark the most minor changes made to a standard document. IEEE describes this as:
“A document that contains only grammatical corrections to, or corrections of errors introduced during the publishing process of, an existing IEEE standard.”
Basically, the unique characteristic of an erratum document is its basis in the comparison of the final balloted version of the standard to the published version, removing any errors that might have emerged during that process.
An example of this is the erratum to ANSI/AAMI/IEC 60601-2-19:2009 - Medical Electrical Equipment Part 2-19: Particular requirements for the basic safety and essential performance of infant incubators, which is ANSI/AAMI/IEC 60601-2-19:2009 ERRATUM. This erratum establishes the insertion of a table into the document, in addition to some other changes.
Please note that many errata could also be considered to be corrigenda. In fact, the erratum referenced in the last paragraph, which was published by U.S. national standards bodies, is actually considered to be a corrigendum internationally by IEC.
Corrigenda and errata are both available free on the ANSI Webstore, regardless of the standard that they adapt. Search the ANSI Webstore for any standard amendments, corrigenda, or errata that might be useful to you.