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 russell.vernon**At_Symbol_Here**ucr.edu www.ehs.ucr.edu 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! www.cshema2006.org === 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 odors? 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 Yung: 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 --------------------- 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) dmdecker**At_Symbol_Here**ucdavis.edu Co-Conspirator to Make the World A Better Place -- Visit www.HeroicStories.com and join the conspiracy ==== From: "paracelcusbombastusvon**At_Symbol_Here**juno.com" 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 cabinets. (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 this. Naomi Kelly Clemson University Environmental Health and Safety Specialist 208 N. Palmetto Blvd. Moorman House Clemson, SC 29631-3012 (864)656-7554 (864)650-8155 Cell Fax (864)656-7630
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