Date: Fri, 19 May 2006 15:03:52 -0400
Reply-To: List Moderator <esf**At_Symbol_Here**UVM.EDU>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: List Moderator <esf**At_Symbol_Here**UVM.EDU>
Subject: 8 Re: [DCHAS-L] Venting flammable storage cabinets

A diversity of answers...

- Ralph

From: "Diane Amell" 
Date: Fri, 19 May 2006 12:20:05 -0500
Subject: Re: [DCHAS-L] Venting flammable storage cabinets

NFPA 30 Appendix A also recommends that, if a cabinet is vented, that  
the "cabinet should be vented from the bottom with make-up air  
supplied to the top," so that would be acceptable.

(One of the best things we ever did here was to subscribe to the NFPA  
Codes Online.)

- Diane Amell, MNOSHA

From: "Randy Ryan" 
Subject: Flammable storage cabinets
Date: Fri, 19 May 2006 11:11:49 -0700
Organization: University of Arizona

The policy may be to not vent the flammable storage cabinets for  
flammability reasons but common sense dictates that they  be vented  
for human health hazards. Go to a well stocked flammable storage  
cabinet, open the door and draw a deep breath. What you smell are the  
same compounds you are using the fume hoods to avoid. Many of the  
organic chemicals with low vapor pressure are released through the  
caps, screw cap connections and or are somehow released into the  
cabinet. Opening the door releases a bolus of concentrated vapors  
into your face and into the room. I worked with B-mercapto-ethanol  
(the  compound is used as an odorant for natural gas) for years. The  
stuff gives me a headache. If we stored it in the unvented flammable  
storage cabinet, I smelled it every time we opened the door. Putting  
it into a vented storage cabinet and the problem went away.

The flammable storage cabinets are designed to be vented with a  
perforated bung to prevent flame extension out of the cabinet. The  
two solid bungs (at top and bottom) can be easily be replaced with a  
perforated bung (if it is not already built in) and piping installed  
(with the perforated bung still in line) to an exhaust system (same  
ductwork as a fume hood). Sidestepping the issue based upon 'NFP'  
recommendations for fire or cost is paramount to exposing the users  
to unnecessary chemical hazards.

This is my opinion and for the past twenty years the issue has been  
around. SOMEONE (EPA, OSHA, ?) needs to weigh in at the national  
level and balance flammability/ product liability with human health  
hazard and render an opinion and guidelines.

Randy Ryan
Assistant Director
Agricultural Experiment Station
College of Agriculture and Life Sciences
The University of Arizona
Forbes 314
1140 E. South Campus Dr.
PO Box 210036
Tucson, AZ 85721-0036
Phone (520) 621-1845
FAX (520) 621-7196

Subject: RE: Venting flammable storage cabinets
Date: Fri, 19 May 2006 09:39:41 -0700
From: "Russell Vernon" 

Adding to the thread...

I strongly encourage the venting of flammable storage cabinets at  
both the top and bottom ports. On our campus it is a requirement for  
new construction.

It is true that UL rates the cabinets un-vented. Properly venting the  
cabinets will not compromise the fire protection and will prevent  
unnecessary personnel exposure to the chemical vapors of the  
materials stored.

Even the University of California as a whole can't agree on requiring  
venting 100% of the time. Here's the relevant paragraph from our  
Laboratory Design Guide:

D.	Venting Hazardous Material Storage Cabinets
1.	Flammable liquid and corrosive material storage cabinets,  
including those built into laboratory casework, may be vented. If  
vented, they shall be connected directly to an exterior exhaust duct  
above the fume hood trim or balancing damper.
2.	If a flammable liquid storage cabinet is ventilated, then it shall  
be connected through the lower bung opening to an exterior exhaust in  
such a manner that it will not compromise the specified performance  
of the cabinet. The other metal bung shall be replaced by a flash  
arrester screen provided by the manufacturer with the cabinet.
3.	If the cabinet is not vented, then it shall be sealed with the  
bungs supplied by the manufacturer.
24 CCR, Part 9, 7901.11.1.1
Good Practice

Russell Vernon, Ph.D., NRCC-CHO
Laboratory / Research Safety Specialist & Integrated Waste Manager
Environmental Health & Safety
University of California, Riverside
900 University Ave.
Riverside, CA 92521
Direct: (951) 827-5119
Admin: (951) 827-5528
Fax: (951) 827-5122
Join us for the 2006 CSHEMA Conference at the Disneyland Resort in
Anaheim, California
The nation's premiere conference on campus health, safety and
environmental management!

From: "Michael E. Green" 
Subject: Re: [DCHAS-L] Venting flammable storage cabinets
Date: Fri, 19 May 2006 11:48:47 -0400

What about using an open dish of charcoal to adsorb the
               Michael Green
               City College of New York


From: "Debbie Decker" 
Subject: RE: [DCHAS-L] Venting flammable storage cabinets
Date: Fri, 19 May 2006 08:45:45 -0700


As you have already heard, venting is not recommended.  When a user  
wants a cabinet vented, I make the requirements stringent (read:  
expensive) and they back off from it.

If the users want vented flam cabinets, the cabinet must be vented  
directly into the general lab exhaust - NOT into the fume hood!  The  
vent must be 304 stainless, not pvc or polypropylene (which supports  
combustion) and vented through the holes already in the cabinet.  No  
new holes in the cabinet that could compromise fire safety.

There exist after-market smell scavengers.  Labsafety Supply markets  
VapRGard that is basically an activated carbon bed to absorb organic  
odors in cabinets.  They work pretty well.

Hope this helps,
Debbie M. Decker, Campus Chemical Hygiene Officer
Environmental Health and Safety
University of California, Davis
1 Shields Ave.
Davis, CA  95616
(530)754-7964/(530)752-4527 (FAX)
Co-Conspirator to Make the World A
Better Place -- Visit and join the conspiracy


From: "paracelcusbombastusvon**At_Symbol_Here**"  

Date: Fri, 19 May 2006 16:31:25 GMT
Subject: Re: [DCHAS-L] Venting flammable storage cabinets

My company has installed several flammable cabinents and "buildings"  
at locations through-out the US and have found tremendious variablity  
in in  stallations.  One fire marshall/engineer required a powered  
vent to the outside.  Others say nothing or use as supplied by the  
manufacturer.  If  you vent, do so to the outside in such a manner so  
any potential emissi  ons do-not pool or are capable of being pulled  
back into the building th  rough ventilation or open doors or  
windows.  Pay special attention to th  e aerodynamic effects of the  
building in relation to the vent and make s  ure to install spark and  
flash-back arrestors.

Check with the locals and get written approval.
Lynn K

Date: Fri, 19 May 2006 11:42:53 -0400
From: Ken Simolo 
Subject: Re: [DCHAS-L] Venting flammable storage cabinets

I am one of those who does not like unvented flammable storage  
cabinets.  I prefer the cabinets to be HIGHLY vented.  However, I do  
not install flammable storage cabinets to increase the amount of  
chemicals allowed in the room.  I like to look at the overall safety.

If the chemicals were on an open shelf or bench, they would be  
exposed to flames/heat.  Being in a highly vented cabinet does not  
greatly increase this exposure risk especially if flame arrestors are  
used.  I consider the buildup of fumes/odors in an unvented or poorly  
vented cabinet to be an unnecessary exposure risk for nuisance and  
health reasons.  Because the air turnover rates in our wet labs are  
so high (12 - 16 air exchanges per hour, sometimes more), I would  
prefer to see either chemicals on open shelves or in highly vented  
cabinets.  The fire marshals do not like the fact that we vent the  

(As a point of information, all of our exhausts are individual  
exhausts that run to the roof and are plumbed with stainless steel  
ductwork until they reach the vertical transite runs.)

Ken Simolo

Date: Fri, 19 May 2006 13:01:47 -0400
From: naomi 
Subject: Re: [DCHAS-L] Venting flammable storage cabinets

We recommend venting the cabinets if the flammables are also highy  
toxic. You should use metal ducts to maintain a fire barrier. The  
reason for specifying metal ducts is to maintain a fire barrier.  
However, metal pipes do not have air-gap insulation, so are lower  
fire rating than the cabinet itself. Therefore, you will need to  
install a fire barrier at the duct connection to the cabinet. eg. fit  
either a flash arrestor or flameproof mesh screen in place of the bung.

If your fire marshall will allow it, you can use plastic pipe if you  
fit an intumescent fire collar around the pipe, fixed to the cabinet.  
In a fire, the collar will close like a sphincter, crushing the pipe,  
and sealing the cabinet.

You should check with your fire marshal before making any decision on  

Naomi Kelly
Clemson University
Environmental Health and Safety Specialist
208 N. Palmetto Blvd.
Moorman House
Clemson, SC 29631-3012
(864)650-8155 Cell
Fax (864)656-7630

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