Q. Are pass thru fume hoods considered ‘High Performance Hoods’?
A. Pass Thru Fume Hoods are not high performance hoods. Under good conditions, with one sash open between 12” and 18”, the hoods can contain at lower velocities. But, performance is different for each installation and dependent on lots of variables. To achieve maximum hood performance our experience shows that the air flow amount needs to be field adjusted for each pass thru hood.
Pass Thru Fume Hoods have a sash on opposite sides allowing users to access the work surface from either side. They are very practical in some applications and look really cool. They are also some of the most difficult hoods to design into Lab HVAC Systems. It is critical to operate a Pass Thru Fume Hood with one sash closed at all times. That’s how they are designed to work. Alarms can be provided to warn users of improper use (both sides open at once).
An alternative to the pass thru hood is the teaching hood. On a teaching hood the baffles are clear to allow viewing through the back of the hood (see photo). The teaching hood can be designed as a High Performance Fume Hood.
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