Tan I believe the "Emergency Purge Mode Switch" works well for fumes, vapors, and some light mists, not so much for flammables that are combusting. The instruction manual/instructions/vendor/installer should have mentioned this. To put out active fire in a hood or the ductwork, a built-in Fire Suppression system needs to be installed. The purge fan only increases the air flow - which you have discovered. More responses from the rest of the list to follow, I'm sure. Bill Parks CHST, CHMP, CEHT, CIE(pending), LSP(C), RPIH 630/380-4032 **Providing sound Industrial Hygiene, Occupational Safety and Health, Environmental Health & IAQ, Environmental, and Laboratory support services and solutions for over 25 years** --- On Fri, 3/5/10, Tan Khai Sengwrote: > From: Tan Khai Seng > Subject: [DCHAS-L] Emergency purge mode for fumehood > To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU > Date: Friday, March 5, 2010, 10:36 AM > Hi everyone > > for some fumehood, especially the VAV fumehoods, they come > with an emergency purge button which is supposed to increase > the exhaust rate in the event of a spillage. > > I have just encounter an incident where a distillation was > wrongly set up, the set up went flying after 2 hours and > toluene was spead all over the fumehood. The researcher > instinctively close the sash fully and activate the > emergency purge mode. by then, the toluene had ignited and > the activation of the purge mode actually fanned the fire. > the fire was big enough to melt the flexible duct connecting > the fumehood to the exhaust duct. the researcher was able to > contain the fire within the fumehood and extinguish it with > the fire extinguisher. > > we are debating over the question of whether to activate or > not to activate the emergency purge button. > > > > any advise? >
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