How to Use a Laminar Flow Hood

Many biological and chemical experiments require researchers to keep materials and equipment free from environmental contamination. A contaminated Petri dish or chemical solution means a flawed experiment. Laminar flow hoods, also called clean benches, prevent contamination by pulling air through a HEPA filter before it flows into the hood. The air then flows out horizontally, toward the user. Because of the way the air flows, laminar flow hoods protect materials under the hood, but do not protect the user. For this reason, chemical fume hoods and biosafety cabinets are necessary when working with potentially harmful substances.

• 1

  Close the hood and turn on its germicidal ultraviolet (UV) light. Let it run for several minutes. This disinfects the surfaces inside the hood.

• 2

  Turn off the UV light. Turn on the blower and the regular light.

• 3

  Raise the hood slowly until you feel resistance, and then stop. Raising the hood beyond this point reduces its effectiveness; many hoods have a warning system that will buzz if you raise the hood too high.

• 4

  Wear laboratory gloves, and wipe them down with alcohol every time you insert your hands under the hood.

• 5

  Wipe the surfaces inside the hood with alcohol on a clean paper towel, to provide further disinfection. Wipe the surfaces of all materials you intend to use before placing them into the hood.

• 6

  Move the supplies for your procedure inside the hood. Keep them a few inches back from the front of the hood to ensure that they remain uncontaminated. Do not place them too far back, as this may interfere with the airflow.

• 7

  Remove all of your supplies when you are done using the hood. You should never store anything in a laminar flow hood.

• 8

  Wipe down the surfaces inside the hood with alcohol once again, and close the hood.

• 9

  Turn on the UV light again. Let it run for several minutes, and then turn it off.