I recently went shopping for PT landscaping timbers. I noticed that the tag on the ends read "Treated To Refusal". Not knowing what that meant, I look ed it up.
"Treated To Refusal" means that they pressure treat the wood until it will no longer accept any more treatment. In other words it "refuses" any more t reatment.
There are apparently no firm standards for the amount of treatment a "Treat ed To Refusal" product must contain. Under the same treatment conditions a wet piece of wood will refuse further treatment much sooner than a dry piec e of wood. A hard piece of wood will refuse further treatment much sooner t han a soft piece of wood.
What this means for the consumer is that you could buy 20 pieces of "Treate d To Refusal" wood from the same supplier and get 20 different levels of tr eatment. You basically have to hope that the manufacturer had some level of quality control in place and wasn't simply grabbing soaking wet wood and r unning it through their treatment process.
While the following piece may be slightly biased, the point it makes is tha t wood that is labeled as "Treated To Refusal" does not meet International Building Codes because the consumer/contractor/inspector has no idea how mu ch treatment the wood has accepted.