Hood Awareness
The hoods are an integral part of your research toolkit here at Princeton Chemistry, and their care and maintenance are essential to helping them function at their peak. With that in mind, Facilities and Safety Manager Stellios Maroulis created this series of lessons to familiarize users with best practices for hood use.
Hood Awareness #1 Fume Hood Sash Stoppers
The fume hoods in our building are like a fine sports car. Like anything else that is meant to be kept and cherished for many years to come, they require a little TLC. What better way to show some care for your work area and ultimately to the environment?
For Part #1 of the Hood Awareness series, we’ll start with something that has become a hot topic and requires urgent attention: the fume hood sash stoppers.
The fume hoods have two open positions: the first stop is 600mm, which is the normal opening; and the second stop is 900mm for a higher reach. It is really important that you don’t go beyond the highest sash stop because going above the 900mm mark will trigger a hood alarm.
Above all, do not remove the sash stop: removal of sash stops is dangerous because it allows the user to bypass the fume hood safe face opening area of operation.
You may ask why this is so important. For starters, the height at which a hood sash is left open will trigger an air flow damper to open and close, as well. These sash locations are the fume hood’s happy place. Think of them like the gears of a car; you don’t want to rev the car too high or you will damage the transmission.
The reason for not removing the sash stops is because, well, our Special Facilities Team will just put new ones back on anyway. So just don’t bother.
The third and perhaps the most important reason is because eventually your hood fume hood sash will get stuck. This could wreak havoc to your hood and even the entire lab.
Take a look at the pictures below for some visual cues. Questions and concerns should be directed to Stellios at: [email protected]
The tabs to the left here are sash stoppers, with the lower stopper marking 600mm and the upper marking 900mm. These stoppers are not to be removed.
The green light above the sash stoppers indicates that the hood is open to an ideal height. Please make sure the green light is "on" when your sash is open.
The yellow light indicates that the sash is NOT at an ideal position. If this yellow light stays on too long, an alarm will go off.