The flow visualization helps to identify potential locations within the enclosure and at the sash opening where eddy currents and turbulence are likely to form. Smoke tubes and candles are used to map out the flow pattern which then enables us to improve on the flow dynamics generated by our fume hoods. The face velocity uniformity test evaluates the uniformity of the inflow velocity at various points across the sash opening while the final part, i.e. the SF6 containment test, evaluates the containment efficiency. A very sensitive SF6 particle detector, capable of reading as low as 0.01ppm, is used in the detection of leaked SF6 during the containment test.
The derived performance as determined by the smoke visualization test and the face velocity uniformity measurement provides a valuable indicator to the containment property of the fume hood. The SF6 containment test provides the ultimate proof in establishing this sequence. If the results of the smoke test and the face velocity test are good, then the containment capability of a fume hood is considered good.
For further information on the test method and observed results, please .
Here in Esco, we are capable of conducting the complete ASHRAE110-1995 test in our laboratory.