This is the first time I have seen a published chart from a clothing manufacturer that has layering values for tested combinations. Thought I would post it here for info although I am hesitant as it is for one specific manufacturer. Does anyone know of other similar charts done by others?

Nothing other than the few combinations that show up on Hugh's web site which seem to be targetted towards utilities.

My company uses Tyndale, thanks for the heads up. I've also not seen data like this published.

Westex has published layering data for years.

Very interesting. My training had stated that 'layering' to achieve an HRC rating was not allowed and I have been teaching that in my classes. I will have to research this and perhaps update my lectures.

Layering has always been allowed. What changed is that at one time you simply added the ATPV values. Now you are not allowed to add ATPV values. However layering was never disallowed. The change was that testing had to be done to verify the ATPV of the combination. The silver lining is that the combination is not additive...it exceeds additive ratings.