Fume Hoods Are Used To

Proper Work Practices

The level of protection provided by a fume hood is affected by the way in which the fume hood is used. No fume hood, however well designed, can provide adequate containment unless good laboratory practices are used, as follow:

The hood user should know the normal operating configuration (NOC) of the hood and should design experiments and then that this configuration tin be maintained whenever chancy materials are at risk. The NOC refers to the position of the sash established when the hood was installed and certified (i.e. how far open is the maximum prophylactic sash position). This is where the survey sticker with arrow is located.

Before using the hood, the user should check the hood survey sticker to make up one's mind where the sash should exist positioned for optimum containment for that particular unit.

The hood user should also check the magnehelic guess or other hood functioning indicator and compare its reading to the reading indicated on the hood survey sticker. If the reading differs significantly (20% or more than for a magnehelic gauge) from that on the sticker the hood may non be operating properly. Contact EHS with hood location and contact information.

Never use a hood to control exposure to hazardous substances without first verifying that information technology is operating properly.

To optimize the performance of the fume hood, follow the practices listed below:

Mark a line with tape vi inches behind the sash and keep all chemicals and equipment behind that line during experiments. This will aid to go on materials from escaping the hood when disturbances like air currents from people walking past the hood, etc., interfere with airflow at the face of the hood.

Poor	Practiced	All-time

Poor placement of materials.	Expert placement of materials.	Best placement of materials.
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Proceed the sash completely lowered whatsoever time an experiment is in progress and the hood is unattended. Note: Lowering the sash provides additional personal protection from projectiles and can also result in meaning energy conservation. Continue the hood sash make clean and clear.

Check area around the hood for sources of cross drafts, such as open up windows, supply air grilles, fans and doors. Cross drafts may cause turbulence that tin allow leaks from the hood into the lab. Also, avert placing fans or equipment with fans in the hood in an orientation that causes the fan to blow out of the hood as the inward catamenia is unlikely to exist strong plenty to keep air and possible contaminants from escaping out of the hood.

Extend only hands and artillery into the hood and avoid leaning against it. If the hood user stands upward against the face up of the hood, air currents produced by turbulent airflow may transport contaminants into the experimenter's breathing zone.

Visually inspect the baffles (openings at the top and rear of the hood) to be sure that the slots are open and unobstructed. 1000 eep baffles and other ventilation openings clean, free of accumulating dust, and unobstructed by collections of numerous containers. The work surface of a smoke hood is not the identify to store materials. Information technology is meant to keep hazardous materials from being inhaled during manipulation.

Keep vents and baffles unobstructed.

For optimum functioning, suit the baffles when working with high temperature equipment and/or heavy gases or vapors. See effigy below for suggested baffle positions.

Normal	Hot Work	Heavy Gases

Normal baffle positioning	Bamboozle position to utilise for hot work	Bamboozle position for heavy gases

Normal baffle position all slots are evenly opened.

Loftier temperature work such as using hot plates; lower slots are minimized since heated vapors tend to rise

Heavy gasses and vapors are better captured when upper slots are minimized

Do non cake slots. If big equipment must be placed in the hood, put information technology on blocks to enhance information technology approximately 2 inches above the surface so that air may pass beneath information technology. See figure below.

Poor Placement	Skillful Placement

Poor large equipment placement.	Practiced large equipment placement.

Place large or bulky equipment near the rear of the fume hood. Large items virtually the face of the hood may cause excessive air turbulence and variations in face velocity.

Practice not utilize the hood every bit a storage device. Keep only the materials necessary for the experiment within of the hood. If chemicals must be stored in the hood for a period of time, install shelves on the sides of the hood, away from the baffles.

Provide secondary containment for containers that could break or spill, to minimize the spread of spilled liquids. Dishpan type containers are provided by EHS upon request. Contact EHS or use the Safety Supply Gild Form (login required).

Items contaminated with odorous or hazardous materials should exist removed from the hood but later on decontamination or if placed in a closed outer container to avoid releasing contaminants into the laboratory air.

When using cylinders containing highly toxic or extremely odorous gases, buy only the minimal practical quantity. Consider using a flow-restricting orifice to limit the rate of release in the event of equipment failure. In some circumstances, exhaust arrangement command devices or emission monitoring in the exhaust stack may be advisable.

All electrical devices should be connected to receptacles located outside the hood to eliminate the potential for electrical arcing that could ignite a flammable or reactive chemical.

Exercise NOT USE A HOOD FOR Whatsoever Function FOR WHICH IT WAS Non INTENDED. Certain chemicals or reactions require specially constructed hoods. Examples are perchloric acrid or high-pressure reactions. Most special utilize hoods are labeled with the uses for which they are designed.