Fume Hoods-Environmental Health & Safety - Carnegie Mellon University

Friday, April 1, 2011

Fume Hoods

For those of us who work with hazardous materials, a properly operating fume hood is a necessity of our job.  Ensuring that the hood is working properly, given the age of the systems in some of our buildings, is quite a challenge to say the least!  EH&S, FMS and you, the reader, all have roles in the process of making sure our fume hoods are properly protecting us from the materials being worked with.

Facilities Management Services has the responsibility to ensure that the fume hood is operating properly, that is, providing the proper, balanced air flow through the system.  Our FMS personnel are very good at understanding our systems and making routine repairs.  As system parts break, however, they are not always easily replaced and often time parts are no longer available.  Certain changes in the system may require a full building rebalancing of the hood flows throughout.  A daunting task indeed.

EH&S has the role of testing to see whether there is a problem with the operation of the hood.  Jeff Harris of our office takes care of this most times-he, too, is very well versed in the operation of our hoods and the exhaust systems, and can offer guidance on your options when the hood is not working correctly.

Finally, you have a very important role in the proper operation of the fume hoods.  Be sure that the sash is located in the proper operating location for optimal flow, when you do your work.  (Keep in mind that the hood is designed to operate at 80-120 fpm face velocity.  Higher flows are NOT better-this creates turbulence which may cause fumes to travel out the front of the hood!)  Also, be sure that you are not overcrowding the hood with stored items.  These stored items often lead to blocked air flow which in turn defeats the proper transfer of your chemicals AWAY from you.  It is important that you NEVER use a red-tagged fume hood-it is a serious hazard to use an improperly functioning hood. 

If you suspect your hood is not working properly, EH&S can confirm this.  If repairs are needed, a work order to FMS must be submitted.  Keep in mind that EH&S can assist you with a poorly functioning fume hood, but we do not do the repairs ourselves.