A fume hood that meets its brochure face velocity and still leaks at the sash is not a containment device. Specify the work, the duct and the test — then buy the cabinet.
1. Start from the chemical, not the width
Acids, solvents and powders ask for different liners and scrubbers. Write the reagents first. Width is decided after the work surface and the number of operators.
2. Face velocity is a range, not a number
0.4–0.6 m/s at the sash is typical. Ask for a smoke test at the working sash height with the room HVAC running.
3. Ducted vs ductless
Ductless hoods are for known, low-volatility work with a rated filter stack. Anything you cannot name belongs in a ducted hood with a roof fan.
4. Site checks before the PO
- Make-up air for the hood
- Sash alarm
- Service fixtures with valves outside the sash
- Containment test in the quote
5. Walk-in hoods
Tall reactors need a walk-in, not a bench hood with the sash yanked up. Send the process and we will specify the hood.
