Basic Fume Hood Safety Guidelines

One of the most important pieces of equipment in any laboratory environment is the fume hood. Fume hoods, when used properly, help protect lab employees and students working with toxic or volatile chemicals and compounds.

The fume hood serves as a physical barrier between the employee and the harmful fumes, fires, explosions and spills that might result from handling or experimentation. Because of this, fume hood safety is extremely important and can help protect your employees and student workers from injury.

Even though fume hoods are designed to protect against unexpected reactions of volatile chemicals, laboratory workers must serve as the first line of defense against. The equipment can only perform and protect if used properly. Operators must follow some basic fume hood safety guidelines to prevent accidents, but before we get into those specifics, let’s quick outline the basic components of a fume hood.

What is a fume hood?

A fume hood essentially looks like an enclosed industrial workbench. To break it down, a fume hood is made up of:

The body: The body of the fume hood contains a work surface, enclosed completely on three sides, on which lab personnel can conduct their experiments / research.

The sash: The sash is the fourth side to the hood, basically a window between the employee and the volatile compounds he or she is working with.

The exhaust duct: The exhaust duct releases any contaminated air to the outside. Usually this duct is connected to the building’s HVAC infrastructure, but there are ductless fume hoods available if flexibility, lower cost, and energy efficiency are key drivers for your business or institution. 

The baffles: The baffles are slotted panels that control the amount of air flowing into the hood from the surrounding environment.

Fume hood safety before and during usage

So, now that you understand the basic construction of a fume hood, let’s get into the basic principles of fume hood safety. There are steps you must take before you even utilize the fume hood, so let’s review.

1. Before using the fume hood, make sure you have been trained in proper use of the equipment. If you don’t know how to use it, ask someone to demonstrate.
2. Understand the potential reactions of the chemicals you are working with (could this chemical explode, liquefy or evaporate under certain circumstances).
3. Open the sash to the proper operating height. Note: If the sash is too high, there is not enough of a barrier between you and the chemicals to provide protection.
4. Check that the air gauge shows that air flow is within the required range.

Now you are ready to use the fume hood! That said, the following safety precautions should be kept in mind while you’re using the equipment.

1. Don’t ever let your head enter the fume hood beyond the sash (this is not going to protect you if something happens within the fume hood).
2. Use eye protection!
3. Try to limit motion around and in front of the hood while you're working. Excess movement could cause the fume hood to vibrate and disrupt airflow.
4. Don’t block baffles or exhaust slots while working in the fume hood, this would prevent air from flowing into and out of the hood.
5. Keep all materials at least six inches from the sash opening inside of the hood.
6. When not working in the hood, close the sash and never store any chemicals inside the hood while it’s not in use.
7. Know your laboratory’s action plan in case of an emergency while handling toxic chemicals.

Final Thoughts 

The last thing you want to worry about is a workplace injury or major emergency. No matter how state-of-the-art your equipment may be or how thoughtful your laboratory design is, if employees and other users are not properly trained on the use of the fume hoods, their safety is at risk. 

For further reading in fume hood safety, check out this OSHA quick fact sheet.