Chemical Fume Hood Operation - Urgent Help Required (Jul/01/2008 )

Hey all,

There is a bit of an on-going query in our lab relating to the operating level of our chemical fume hood. The minimum operating level is clearly marked on the hood but it is routinely ignored and I have been told that the "minimum operating level" acts as only a "guideline!".

Common solvents used in the hood include ethyl acetate, acetone, dichloromethane, acetonitrile and ethanol.

The latest problem has arisen due to the lack of air-exchange in the lab. A senior person has suggested that the fume hoods be turned on fully and opened fully to allow for air-exchange to occur more frequently. Surely this is a very bad idea?? Will this not cause air to be pushed out of the fume hood and also the rate of air extraction in the lab will not be affected by having the fume hood open?? Even at times when chemicals are not being used in the hood, the sash should surely be kept down?

Any technical info / comments are greatly appreciated. We are trying to ressolve this matter urgently.

Thanks....

The mark in the hood isn't the minimun operation level, is the optimum level that make sure the filters are functioning as should be. Any cm over the mark and the operator is expose to the fumes. Leaving the door fully open is the same that mixing the chemicals over the lab. bench, there is no protection to the operator.