Good morning,

When we moved into our 'wet lab' building about 15 years ago, each fume hood was equipped with a mechanical stop placed at 18 inches, as well as an alarm system governed by Phoenix controls.  In this time, we have only had a malfunction with an alarm (didn't go off) in one hood.  The mechanical stop is on one side of the hood, and can be manually released to raise the hood above the stop point in order to set up apparatus, etc.

Because the mechanical stop is easy to 'hit', even though students are generally careful, over 15 years we have recently seen two incidents of the sash cable becoming frayed and as a result, the sash is difficult to open/shut.  Repairs are costly plus a large inconvenience as the hood and solvent cabinets underneath must be emptied and deconned.

Apparently these 18" mechanical sash stops are rare in other institutions per our vendor; and we are planning to remove them.  We were thinking of placing labels denoting the 18 inch mark after the stops were removed, but this would mean installing about 70-80 labels pretty quickly.  Not a difficult task, but enough time spent with a tape measure that I wanted to ask...

Does your institution rely on just the alarm going off if the sash is raised above the setpoint, or do you also have a visual guide to the maximum set point on the side of each fume hood?  We would confirm the alarms were working at the beginning of each semester as well as the beginning of the summer research period.

thank you!
Margaret

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Margaret A. Rakas, Ph.D.
Lab Safety & Compliance Director
Clark Science Center

Smith College
413-585-3877 (p)

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