Considerations for Floor-Mounted Fume Hoods

There are many different types of fume hoods, each best suited for a different application. One special type of fume hood is the floor-mounted hood, previously referred to as a walk-in hood. Disclaimer: You should never walk in to a floor-mounted fume hood without direct advice of your Chemical Safety Officer or refer to a hood as walk-in! 

What makes these hoods so special is obvious – they sit on the floor rather than the benchtop. But more than that, they can be enormous. A benchtop hood typically goes up to about 8 feet wide, though they can be larger. A floormounted hood can be twice that. Labconco offers standard part numbers for floor-mounted hoods up to 16 feet wide but that isn’t necessarily the largest they can be.

Width isn’t their only advantage. They also come in multiple depth options. It’s possible to have a 16’ wide hood that’s over 4’ deep. Labconco’s standard interior dimensions are 46.7” deep and 84” high with a sash opening 73.5” high but larger hoods may be customized in some instances.

Obviously that’s not the typical size, but it is a possibility – and one that is needed for some types of equipment. Floor-mounted hoods are great for working with large equipment and apparatus, using smaller equipment that is kept on a cart and shared among labs, or when using large drums of powders or chemicals.

When selecting a floor-mounted hood, you first need a risk assessment of what you’re working with, what type of electrical classification your room will need, and how you will handle potential spill containment, among other topics.Your organization’s Chemical Hygiene Officer or the Authority Having Jurisdiction on safety must do this. You must also assess if your mechanical system can support the hood(s) and more. Knowing the chemicals you’re working with determines the type of fume hood that is safest for your work.

The electrical classification will tell you if you need an electrically classified room and explosion-proof (EP) equipment. 

The mechanical system assessment is vital to the success of the hood. Can it support the CFM requirements of the hood? Can it provide enough supply air to replace the tempered air that’s being exhausted? You must be sure the hood(s) can be properly supported or you risk failing to properly exhaust the fumes. Determining your CFM requirements may also help identify the size of hood you need.

Next, you need to determine how much space you need inside the hood. Do you just need enough space to roll in a cart? Or are you placing large equipment permanently inside the hood? If the equipment will be kept in the hood, it’s important to verify how much room is needed. This means not just the overall dimensions of the equipment, but what is required to operate and maintain the equipment? Is there a door that needs to be able to be opened? Will a lever need to be raised? Or does part of the equipment rise during use or loading that adds to the overall height of the equipment? 

Determining the dimensions needed for the equipment itself is first. Then consider if there are any power plugs, fixtures, etc. that need to be accessible on the equipment. Making sure you  have enough interior width, depth and height is vital to selecting the right floor-mounted hood. Don’t forget to account for how you will manage and organize hoses and cables. 

Next, consider if there are any accessories needed for the hood itself. Do you need service fixtures for gas, water, vacuum, and so on? Do you need power outlets? Or passthrough ports for hoses or cabling? How about an airflow monitor? While not required, they are an important step to ensuring safety. Also consider what type of sashes you need – horizontal- or vertical-sliding. Are you using a vacuum pump? Where the discharge from the pump will go needs to be considered as well.

It’s equally important to consider the placement of the hoods. Being near vents, door, windows or high traffic areas can affect the air flow into the hood. And if you need to service the hoods, you may need to access the side panel – is that readily available or are the hoods going to be placed up against each other?

One final, but very important, consideration is one that is often overlooked until the day of delivery. How are you going to get it into the lab? You need a route into the building that will accommodate the size of hood you are needing. Floor-Mounted Hoods are often delivered in sections, on pallets larger than the hood itself, but they can still be massive in size. Don’t overlook the logistics of physically navigating your building.

Once you’ve decided on the size of hood you need, you can start selecting the model. Labconco offers both filtered and ducted floor-mounted hoods. Protector Echo Floor-Mounted Filtered Hoods are unique in that they require no ducting. They use comprehensive carbon filtration to remove fumes and recirculate the air back into the lab. These are great for when ducting out of the lab is difficult, but there are certain limitations of the filter so each potential use must be reviewed using a Chemical Assessment Form prior to purchase. 

Protector XL Floor-Mounted Hoods are traditional ducted hoods. They can handle almost any chemical with the right type of ductwork. These also come in much larger widths than the Echo hoods. Both hoods feature a chemical-resistant, fiberglass-reinforced composite panel liner and can be outfitted with all of the same accessories as benchtop hoods.

Need help selecting a floor-mounted fume hood? Contact us about your application.