A variable-air-volume, hood face velocity, androom pressurization control system has been in operation fof two years at a research center in Warrensville Heights, OH. The system design is simple and has,resulted in an average annual supply air savings of 18,000 cfm in what was previously a 55,000 cfm constant-volume dual-duct system. Testing and development started in May 1985 in a selected occupied laboratory.

The system controls consist of electronic hood face velocity, pneumatic temperature, and room pressurization. The negative lab pressure is being maintained at.O02 velocity pressure relative to the adjacent corridor. The controls are independent of each other and respond to the changes in the laboratory. The design has provided a safer, quieter, more flexible, energy-conserving environment. A two- to three-year program will convert all labor ratory ventilation systems to this design.