From: Yung Morgan <pmorgan**At_Symbol_Here**EHS.UMASS.EDU>
Subject: FW: [DCHAS-L] [DCHAS-L] Fume hoods purge buttons
Date: Tue, 13 Aug 2013 20:50:21 +0000
Reply-To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>
Message-ID: B146A5C95EBD714CB311BE2ABF6C028A091359**At_Symbol_Here**oit-ex2010-mb3

The following is the perspective from our emergency response team leader re: the need for emergency purge buttons for rooms and hoods.  Thank you all for your responses and comments  on this issue.


Best regards,


Yung Morgan, MsPH
Laboratory Safety
Industrial Hygiene Services
Environmental Health and Safety
117 Draper hall
UMASS,Amherst MA 01003
phone (413)  545-2682
Fax  (413) 545-2600
email : pmorgan**At_Symbol_Here**


From: James M. Field
Sent: Tuesday, August 13, 2013 4:20 PM
To: Yung Morgan
Subject: RE: [DCHAS-L] Fume hoods purge buttons


Yung I would add from my perspective the following


Our office has been involved in campus wide emergency response for over 30 years. We maintain 24/7 coverage and operate a full HAZWOPER team. The fire department along with the State HAZMAT team expect us to be on scene to help assess and evaluate any ER to the campus.

For chemical spills in laboratories we generally respond in house and clean these up under our HAZWOPER protocols. The fire chief has worked well with us and wants to be in the loop and is available if we need him. We train with the fire department and the state HAZMAT team on a regular basis. I think maintaining that relationship and fostering the sense of confidence allows you to maintain control of your buildings and your operation. When we request assistance from these groups it is generally a Unified Command Structure with our staff participating in the decision making process. These efforts take considerable time and effort but have paid off in major incidents.


Now to laboratory purge systems.

As the Incident Commander directing an entry I would prefer to have my entry team enter a room with the lowest readings possible. We do not allow entry if readings are at 10% of the LEL and I would prefer that measurements if available are below any IDLH. Our first call as we respond to a spill is to ask if the room is on full purge. If the occupants did not activate the room purge as they evacuated our HVAC people can activate these emergency purges room by room or floor by floor depending on what has occurred. With modern day controls our HVAC staff can operate these from home at any time of the day or night. This simple action makes the room extremely negative and keeps the hot zone small. We allow the purge to continue as our team suits up and we develop our Incident Action Plan. This can take up to an hour or more for an off shift response. The longer the purge is running the better as far as the entry team is concerned. Our initial entry is normally simple, SCBA is a requirement along with robust level B suits. We enter with multiple detector devices usually both PID and multi gas readings are taken. Assess the size and complexity of the spill. Determine the accuracy of what is reported to be spilled and spread adsorbent onto any spilled liquid materials.

As the IC responsible for the safety of the entry team it has been extremely useful to have the room at 12 air exchanges per hour while you prepare for entry. The idea the you can keep the hot zone to a room or a floor is a great asset that can minimize potential exposure and allows the entry team to setup at the lab door versus outside the building. The issue of responder safety whether it is our group, the fire departments or the HAZMAT team is paramount and should be considered when designing a laboratory. These full exhaust emergency purge operations are not run during normal operations and are generally activated by the occupants as they leave the lab during a spill. I am convinced after 30 years of spill response that this simple addition to the building design reduces potential exposure to occupants as they leave and minimizes the potential hazard to the first responders. It allows the response to be conducted with more confidence and minimizes the duration of the spill clean-up.  Our energy engineers were at first reluctant participants but now see the value of these seldom used tools. The last time we trained with the district hazmat team they loved the ability to bring the cold zone up to the lab door and questioned why this was not a design standard for all laboratories.


It seems we have this fight with all design engineers when we build new or renovate any old lab buildings. We go through the same argument every time.

Loss of energy efficiency! How often do you expect to use this tool?

Creates turbulence and could draw chemical vapors out of the hood! No one should be in the lab at this point! We are trying to exhaust the room not the hood.

Talk to first responders and ask them, when making an entry to the hot zone with full protective gear and SCBA do you want to enter a room saturated with vapors at or above the LEL or the IDLH or one the gives you no reading or a very low readings.

Its relatively simple to do during the design build process and the cost is negligible. It just makes sense.




Jim Field

Hazardous Materials Control Manager

EH&S 113 Draper Hall

University of Mass.

Amherst, MA 01003

phone 413 545-5122

Cell 413 427-4897

fax 413 545-2600




From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU]On Behalf Of Monona Rossol
Sent: Tuesday, August 13, 2013 10:06 AM
Subject: Re: [DCHAS-L] Fume hoods purge buttons


Ventilation for laboratories is not my area, although fume hoods and dilution ventilation systems used in art studios, printmaking acid rooms and the like are my field.  I haven't specified a purge system for an art studio, but I'm beginning to think from the conversations on this thread that that is a REALLY good idea.  


We do use a purge system on theatrical stages.  Some unions require a system that will completely clear the area behind the curtain of airborne special effects between acts in under 5 minutes. 


And I can see how a purge system that would keep the atmosphere in a lab somewhat under control in an emergency could be useful.  A purge system might preclude a spill getting out of hand to the point that SCBA would be necessary.  Or it could prevent a solvent spill vapor concentration from ever reaching the LEL.   


I am going to consider this purge idea for some art labs and studios.  For example, I already specify special kind of displacement ventilation system for traditional solvent art painting rooms. There are two settings for air flow for these system, one during painting classes and a lower setting for night time when only the outgassing canvases in the drying rack need exhaust.  It would be so simple to have a third setting that could jack up that flow to purge the room in an emergency.   


One of these painting room displacement systems I recommend was installed in the new art building at UMass-Amherst.  The original purge question came from their EH&S person who is a friend and colleague. Hmmmm.  That's making me think even harder.  In any case, you've all given me something to think on.   Thanks.

Monona Rossol, M.S., M.F.A., Industrial Hygienist

President:  Arts, Crafts & Theater Safety, Inc.

Safety Officer: Local USA829, IATSE

181 Thompson St., #23

New York, NY 10012     212-777-0062



-----Original Message-----
From: David C. Finster <dfinster**At_Symbol_Here**WITTENBERG.EDU>
Sent: Tue, Aug 13, 2013 7:27 am
Subject: Re: [DCHAS-L] Fume hoods purge buttons

I'm surely not a ventilation expert, and I've never heard of a "purge button" before.  However, in addition to Ralph's question below about the purpose of using such a device, as an volunteer firefighter for 20 years I can view this scenario of a "significant spill" as a situation that should only be handled by emergency responders.  Any situation that poses an atmosphere that is not human-friendly and/or a fire/explosion hazard should simply call for an building evacuation with appropriate power shut-downs (to eliminate ignition sources) IF POSSIBLE.   


"We found ourselves using the purge buttons a lot to exhaust the room and the hoods  in an emergency."


I'd re-examine protocols to prevent these episodes rather than re-evaluating response options.


"This is  to allow a  safer environment for emergency personnel to enter the area and do spill clean ups, particularly when the spill happens outside of the hood. "


The firefighters who respond to this will surely be wearing SCBA and have a four-gas meter to check O2/CO/flammables/X  (where is likely H2S).  It is thoughtful of you to consider them but, frankly, they will mostly ignore you and treat any major spill as a worst-case scenario to protect themselves.  Firefighters can't afford to blindly trust information given to them by dispatch since in some instances it a wrong (even when not intended to be.)   The best thing to is to meet the officer in charge of entering crew at the door, give the best information you have, tell them if you think there is any chance that someone is still in the building, and make sure they have master keys.  They know what to do after that.






David C. Finster
Professor, Department of Chemistry
University Chemical Hygiene Officer
Wittenberg University


From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU]On Behalf Of Ralph B. Stuart
Sent: Monday, August 12, 2013 5:50 PM
Subject: Re: [DCHAS-L] Fume hoods purge buttons


> We found ourselves using the purge buttons a lot to exhaust the room and the hoods  in an emergency.


I'm not clear what hazard is being reduced by this strategy. Are you trying to prevent a fire by keeping the concentration of the spill below the LEL? Or are you trying to control levels below the IDLH? I'm not sure that general ventilation will accomplish these goals, as the spill could be a location in the lab where the ventilation system doesn't effectively clear the air. We are finding significant "dead spots" in many of our lab settings�


My personal opinion is that the ventilation system should not be considered part of the emergency response system, as its value in a specific situation is undeterminable.


- Ralph


Ralph Stuart CIH

Chemical Hygiene Officer

Department of Environmental Health and Safety

Cornell University



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