Tim has worked at ASTM for 27 years, the first seven as manager, Standards Development, five years as director, and then four years as an assistant vice-president in Technical Committee Operations. In 2011, he assumed his current role, which includes responsibilities for: Training and eLearning, Proficiency Testing, the Cement and Concrete Reference Laboratory, and the Test Monitoring Center, an ASTM affiliate.

In late 2019, Tim became president of another ASTM affiliate, the Safety Equipment Institute.