The Clean Air Act Amendments of 1990 required states to adopt enforceable volatile organic compound (VOC) regulations. As a result, capture efficiency (CE) test methods were required to be included in the state implementation plans (SIPs). In April 1990, the Environmental Protection Agency (EPA) issued guidance on CE measurement procedures, emphasizing procedures that required a total enclosure.
The EPA received comments from parties concerning the potential excessive costs involved in using the recommended protocols that specify a temporary total enclosure (TTE) for measur