Certifications for A-T Trunnions April 2017 Posted on April 16, 2017May 8, 2020 (April 2017) It's official . . . after careful attention to testing and required documentation, our Trunnion Mounted valves are now certified as SIL 3 capable. Visit the Quality & Certification page underĀ Resources to download the certificate. Posted in Uncategorized.