In a previous post James wrote...
I assume from Bob's post, that the (newer) p-t lumber still has the
retention ratings of things like .40 , .60 etc etc.


YES! The penetration values for the various chemicals used are the same.


--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA
bob at rlmorrisonengr dot com