Provides guidance on the factors which affect the toxic hazard from fires involving electrotechnical products, and provides information on the methodologies recommended by ISO TC 92 (SC 3) for estimating and reducing toxic hazard from fires, as expressed in ISO/TR 9122 (Parts 1 to 6), ISO 13344 and ISO/TS 13571.

There is no single test to realistically assess toxic hazard in fires. Small-scale toxic potency tests are not capable on their own of assessing fire hazard. Current toxicity tests attempt to measure the toxic potency of a laboratory generated fire effluent. Toxic potency should not be confused with toxic hazard.

Although the structure of this standard remains essentially the same, the main changes with respect to the previous edition are listed below:

- Introduction: an explanation concerning the publication of IEC 60695-7-50, a small-scale toxicity test method, reference to IEC 60695-7-51 which covers the calculation and interpretation of test results, an explanation of the alignment with ISO/TC 92 Fire safety.

- The expansion of the scope further clarifies the subject matter and alignment with ISO/TC 92, in particular ISO 13344 and ISO/TS 13571.

- Formulae are given for the calculation of the fraction of the incapacitating dose for each of the asphyxiants, carbon monoxide and hydrogen cyanide.

- Volume fractions that are expected to cause incapacitation (F values) are given for some of the more important irritants.

- The definitions have been greatly expanded and updated. - The subclause on factors determining toxic hazard has been expanded.

- New subclauses include general aspects of small-scale test methods, evaluation of test methods and the relevance of toxic hazard data to hazard assessment.

- A flowchart has been added to outline the stages to be followed for test method assessment. Has the status of a basic safety publication in accordance with IEC Guide 104.