Sulfur Hexaflouride Tracer Gas Evaluations on Hood Exhaust Reductions

Abstract

Proposed facility energy reductions, which include exhaust fan speed and corresponding exhaust volume reductions, demand evaluations of exhaust hoods to ensure adequate containment efficiencies. Sulfur hexafluoride tracer tests were conducted on various designs of exhaust hoods in order to evaluate their performance in an exhaust-reduction mode. Performance tests were conducted on semiconductor-type wet process stations and plating tools operating in Class 100 and 10,000 clean-rooms and a standard laboratory fume hood using ASHRAE Standard 110-1985 “Methods of Testing Performance of Laboratory Fume Hoods” as a guideline. Test results confirmed accepted hood design standards and showed that exhaust reductions can be safe but are highly dependent on design, manufacturer, and the operating environment. Administrative controls are required for any hood exhaust reduction program, and education on the proper use of the exhaust hood, based on its specific design, was found to be necessary. With such controls in place, exhaust fan speed reductions appear to be a feasible approach to reducing the cost of operating an R&D facility.