Dear members, Thank you so much for all your responses for my question on" whether or not to vent flammable storage cabinets". The responses were varied but so very informative and thorough. Here are some examples: !. "NFPA 30-2003, Flammable and Combustible Liquids Code, does not require that a flammable liquids storage cabinet be provided with ventilation or exhaust. It does compromise the integrity of the cabinet because the cabinet is intended to keep a fire outside from getting at the materials inside for at least 10 minutes, said time presumably being sufficient for evacuation of the area. This is especially true when the user merely removes the bung from the 2-inch openings on the cabinet and leave them exposed" 2. Another direct quote from NFPA 30 ." However, it is recognized that some jurisdictions can require storage cabinets to be vented and that venting can also be desirable for other reasons, such as health and safety. In such cases, the venting system should be installed so as to not affect substantially the desired performance of the cabinet during a fire. Means of accomplishing this can include thermally actuated dampers on the vent openings or sufficiently insulating the vent piping system to prevent the internal temperature of the cabinet from rising above that specified. Any make-up air to the cabinet should also be arranged in a similar manner. If vented, the cabinet should be vented from the bottom with make-up air supplied to the top. Also, mechanical exhaust ventilation is preferred and should comply with NFPA 91, Standard for Exhaust Systems for Air Conveying of Vapors, Gases, Mists, and Noncombustible Particulate Solids. Manifolding the vents of multiple storage cabinets should be avoided." 3. Not vent the cabinets at all and requiring that some other types of odor absorbing materials and" door closing and locking of the cabinets to keep the odors down. 4. From our own hazwaste officer and emergency response leader, Jim Field: My understanding is that some institutions require that venting be part of all cabinets installations. The rational behind venting is really more of a personnel exposure issue. The problem has been that many short chain volatile once opened will off gas vapors into the cabinets crating a vapor filled container. We see this with especially the ethers and some of the more volatile acids and bases. These more corrosive liquids present an even greater exposure problem and will eventually corrode the cabinets. Venting these storage cabinets creates a safer environment in the lab and extends the life of the cabinets. Some of the major problems associated with venting flammable storage cabinets is if they are installed improperly they can increase the hazard. The connections to the venting system must follow the mechanical code. The cabinets flash arrestors must be open and used for the supply air and as I understand the problem the flow rate must be very low. The idea is that a high volume flow rate might draw the flame form an impinging fire into the cabinet defeating its purpose. We do have some vented cabinets on campus. The flammable storage cabinets in Conte chemical stock room are vented and I think the under fume hood cabinets in this building have openings for passive exhaust ventilation. I would have to look to verify that.. If you remember, the fire in Conte the flames were all drawn into the fume hood. The fume hood was destroyed but the fire did not extend into the lab or adjacent storage areas. In fact the samples and some of the apparatus in the hood were salvageable. I don't have enough room to list all the responses but if anyone would like to see them, either for or against venting the cabinets, I can send them individually . Again thanks a million for all your help, you are "a terrific group", to quote Monona. Yung Morgan, MsPH Chemical 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**ehs.umass.edu
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