This conversation has prompted me to re-label all of ours. They came labeled "panic button," which seems like a ridiculous label for a red button in a hallway. For a time, we were told they actually turned off the fume hoods, which was simply false, but the rationale was that would be a good thing to do in a case of a fume hood fire and were labeled as such.
Having verified that they do in fact crank up the fume hoods (which are for the most part of a two-stage VAV design), they now bear the following legend:
"PURGE BUTTON: In case of chemical spill or release, press to maximize laboratory exhaust ventilation." No guarantee that pressing it will solve your particular problem, but at least it's truth in labeling.
Don
Donald Abramowitz, CIH
Environmental Health & Safety Officer
Bryn Mawr College
Bryn Mawr, PA