US connector manufacturers have published coatings specifications for connectors and fasteners for use with treated wood, according to industry newsletter Random Lengths. The move follows tests on the corrosiveness of new generation wood preservatives.
One major manufacturer has rated the relative corrosiveness of ACQ (alkaline copper quarternary) and CA (copper azole) as very similar.
The two leading connector manufacturers recommend stainless steel connectors and fasteners. The minimum is hot-dipped galvanized fasteners meeting ASTM A153 requirements and hot-dipped galvanized connectors meeting ASTM A653, G-185.