IEC 60695-6-1:2021 is available as IEC 60695-6-1:2021 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.

IEC 60695-6-1:2021 gives guidance on:
a) the optical measurement of obscuration of smoke;
b) general aspects of optical smoke test methods;
c) consideration of test methods;
d) expression of smoke test data;
e) the relevance of optical smoke data to hazard assessment.
This basic safety publication focusing on safety guidance is primarily intended for use by technical committees in the preparation of safety publications in accordance with the principles laid down in IEC Guide 104 and ISO/IEC Guide 51.
One of the responsibilities of a technical committee is, wherever applicable, to make use of basic safety publications in the preparation of its publications.
This third edition cancels and replaces the second edition of IEC 60695-6-1 published in 2005 and Amendment 1:2010. It constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
- References to IEC TS 60695-6-30 (withdrawn in 2016) have been removed.
- References to IEC TS 60695-6-31 (withdrawn in 2016) have been removed.
- References to ISO 5659-2 have been inserted.
- The scope contains some additional text.
- Terms and definitions have been updated.
- Subclause 3.2 has been updated.
- Subclause 7.1 has been updated.
It has the status of a basic safety publication in accordance with IEC Guide 104 and ISO/IEC Guide 51. This International Standard is to be used in conjunction with IEC 60695-6-2.