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Tackling Common Fume Hood Working Issues

by | Feb 23, 2022

Any equipment could pose some issues during its working and the Fume Hood is not an exception. Let us discuss some common complaints related to the working of a fume hood and ways to resolve them.

Basic Checks

Most often it is reported that the fume hood is not offering adequate suction (airflow). While there could be many reasons, one can always eliminate the most obvious. A common reason is that the ‘Damper’ located in the throat of the fume hood is fully closed or isn’t in the ideal position of the opening. This can be easily corrected by readjusting the Damper manually.

At times the fume hood blower is not connected with the right polarity from a three-phase supply. This makes the blower impeller rotate in the reverse direction. In such an event, there is some suction but not adequate suction. This issue can be easily overcome by reconnecting the blower motor with the right polarity sequence.

Casing Drainage

In places where heavy rains take place, such as Mumbai, there is a possibility of the rainwater finding its way into the blower casing. The accumulated water at the bottom level of the blower casing poses resistance to the free movement of the impeller. This results in lower suction and at the time of restart, the water splashes up. Labguard fume hoods are provided with a drain hole from which the accumulated water can be easily drained. If the drain point is choked with dirt or sediments, it should be cleaned.

Ducting Check

At times users complain about condensation inside the fume hoods. A common cause is the high humidity of the supply air. Another reason is that the exhaust duct is not of the proper cross-section which results in higher air velocities and lower temperature causing condensation. Corrective action can be taken.

Air Dynamics

Relocating a fume hood near a door or a window can adversely affect the airflow. This is due to the eddies and turbulence that get created at such positions. A new supply air damper, that has been added and opens in front of the fume hood, can have a similar effect. These conditions need correction.
Placement of heavy equipment just in front of a fume hood, heavy material, and personnel movement in proximity could also affect the airflow.

Airflow Monitor

Finally, one needs to check whether the airflow monitor itself is malfunctioning. If it shows Air Fail continuously, the underlying cause should be identified and tackled.

With these simple tips, you can keep your fume hood performing at its peak at all times. Just in case you are not able to resolve the fume hood operational issues, you may seek help from Labguard. We are just a call away.

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