Expanded certification, explained
Koppers Performance Chemicals has secured an expanded ground-contact listing for MicroPro® SIENNA Select, extending the micronized copper system’s approved end uses to UC4A applications such as posts, joists, and structural members in direct soil contact. The expanded listing follows a multi-year program of accelerated field exposure and independent laboratory testing.
For treaters and specifiers, the update means a single preservative platform can now span a broader range of above-ground and ground-contact projects without switching chemistries — simplifying inventory, retentions, and quality control across the plant.
Inside the testing program
The expanded certification is backed by a rigorous, repeatable evaluation program built around the AWPA standards that govern treated-wood performance. Below is a closer look at how the data was generated and verified.
Test methodology
Specimens were treated to target retentions across multiple charge sizes and conditioned before exposure. Daily analytical testing at our laboratories tracked penetration and retention to confirm that every charge met the UC4A specification rather than relying on averaged batch results.
Third-party validation
An independent, accredited laboratory replicated the exposure protocol and audited the supporting data package. That outside review is the backbone of the listing — it lets specifiers rely on the certification without re-running the work themselves.
Climate and exposure scope
Field stakes were installed across multiple decay and termite hazard zones to capture the full range of service conditions a ground-contact member is likely to encounter, from humid coastal sites to high-termite-pressure inland regions.
What this means for specifiers
Architects, engineers, and building officials can now specify MicroPro® SIENNA Select with confidence across a wider envelope of code-recognized applications. Because the system retains its lighter, more natural appearance and low corrosivity to fasteners, the expanded scope arrives with no trade-off in finish quality or constructability — giving the design community one consistent, well-documented preservative to specify from deck to soil.