Hello,

I would like to know if ISO class 6 chemical indicators are better or safer than ISO class 5 chemical indicators, noting that in the EN standards, all chemical indicators are considered of class D.

i am confused about which indicator to use and i would like to know if there are any documents or references supporting both opinions.

thank you and best regards,

natali

Hello!

The enumeration of the various indicator classes do NOT imply that the higher the number the better the indicator. The serve different applications, e.g. Class 2 (EN Class B) indicators are designed for the Bowie Dick Test. It is not superior to a Class 1 nor is it inferior to a Class 3 indicator.
The differences between the classes have already been addressed in answers to questions Q00331 and Q00426.
The European classification ends with Class D, but this is more for historic reasons. EN 867 and ISO 11140 are currently undergoing joined revision and ultimately the new ISO EN 11140 will replace EN 867 and the alphabetical listing will disappear.
In addition the ISO Guidance on selecting chemical indicators will undergo revision as well.
Again, the numbers are not hierarchical!

Regards
K. Hahnen