Chemical hood systems shall be designed to protect laboratory workers and to ensure that hazardous chemical vapors originating from laboratory operations shall not be recirculated. The use of variable air volume systems is preferred. Additional requirements include:
- Designed to provide 100 linear feet per minute face velocity at a height of twelve inches.
- Maintain a set point within five percent within one second of any change in fume hood sash position, or changes in the exhaust and/or supply systems; except in those cases where the existing building's HVAC systems are not capable of complying with this requirement.
- Provide flow detectors/alarms visual readout of face velocity.