How Often Should Restaurant Hoods Be Cleaned?

The air in a busy restaurant kitchen is unlike anywhere else. Breathing it constantly would be hazardous for a person’s lungs if not for powerful exhaust systems that constantly circulate air in and out. As these systems do their job, grease and particulate inevitably settle inside the system, restricting air passage, putting more strain on the system, and leaving more unhealthy air in the kitchen. This – in addition to the well known fire risk that a grease-laden exhaust hood brings – is an excellent reason to clean your hood on a regular basis. But how often is the right frequency? When should you clean your restaurant hood? There are regular inspections, of course, but what’s the real answer?

When Should You Clean Your Restaurant Exhaust Hood?

Poor indoor air quality is one of the hazards presented by a grease-laden hood. Another is kitchen fires. There’s no doubt that a greasy vent hood is correlated with fires. In the recent National Fire Protection Association (NFPA) report on “Structure Fires in Eating and Drinking Establishments,” 22 percent of the restaurant fires reported were attributed to failure to clean, and a grease-laden hood will start one quickly. It’s staggering to think that more than one-fifth of all kitchen fires wouldn’t have happened if the hood had been cleaned earlier that day.

Yes, it’s a difficult job, but the risk is real. The best policy is to clean it as soon as it’s filled with grease. And that depends on how busy your kitchen is. Guidelines can help establish a basis for how often you should do it, but if your hood needs to be cleaned every two weeks, cleaning it every two weeks makes for a healthier and safer kitchen workplace. The NFPA sets national standards for kitchen exhaust inspections and cleaning. According to the NFPA 96 Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations, every restaurant and commercial kitchen falls into one of these four categories:

• Monthly: Restaurants using solid fuel such as charcoal or firewood need to be inspected each month. 
• Quarterly: High-volume cooking operations, including 24-hour cooking, charbroiling, or wok cooking, need to be inspected quarterly.  
• Semiannually: Restaurants with moderate-volume cooking operations are inspected twice a year. 
• Annually: Establishments with low-volume cooking operations such as churches, day camps, seasonal businesses, senior centers, ski resorts, are inspected once a year. 

If a fire marshal arrives and an inspection is past-due, several things could happen. They could shut the site down immediately for not adhering to NFPA standards. Or, the fire marshal may provide a time frame to address the vent cleaning, perhaps 48 or 72 hours, and then come back and make sure the vent and hood were cleaned and passed inspection. If the issues haven’t been addressed, the fire marshall could then shut the restaurant down. Sometimes, a fine may also result. If a restaurant is operating beyond the due date of their required kitchen exhaust inspection, the restaurant takes full liability for any sort of loss due to a fire.

Which Parts of an Exhaust System Require Cleaning?

All four major parts of a restaurant kitchen exhaust system need to be cleaned:

• Exhaust hood: This large stainless steel canopy is mounted above the cooking appliances. It is designed to hold the baffles, while funneling the airflow into the ductwork. 
• Baffles: Often made of metal, their primary job is to prevent flare ups from reaching further than 18 inches into the hood and flue. Some baffles are also designed to filter grease and solid fuel embers, though not all baffles are filters. If they aren’t routinely cleaned, they can easily become a major fire hazard.
• Ductwork: Large pipes connect the exhaust hood canopy to the exhaust fan and move the cooking exhaust outside. 
• Exhaust Fans: Fans are typically either found below the ductwork, or all the way up on the rooftop. They’re the powerhouse of the exhaust system — and in order to work efficiently, they should be clean.

How Does Third-Party Hood Cleaning Work?

Typically, it’s the same third-party vendor that inspects the hood or cleans the hood depending on what’s needed. If they clean it, or if it passes inspection, they’ll attach an updated inspection sticker on the side of the hood canopy showing when it’s due for its next inspection. Local fire marshalls often conduct their own separate unannounced inspections annually to ensure that the restaurant is operating within the span on the sticker. Before beginning, the cleaner will do a few things to prepare.

The areas around the hood need to be cleared out, which means appliances get unplugged and moved, pilot lights go out, gas lines are disconnected, and so on. Once the area is emptied, plastic sheets should be hung from the vent hoods and funneled down into a trashcan to catch all of the grease, water and detergent from the cleaning process. Once setup is complete, power washers clean everything from the hood canopy through the ductwork and up to the rooftop. During the long cleaning process, the kitchen is shut down, which means the restaurant is shut down. This often means that exhaust hood cleaning takes place overnight, which necessitates hiring someone to stay and supervise.

Clean Your Exhaust Hood the Restaurant Technologies Way

Thankfully, the days of dealing with messy hood, flue, and fan cleaning are over. Restaurant Technologies offers two solutions that can either completely eliminate the need for future third party kitchen exhaust cleanings or simply reduce the need for hood cleanings by up to 75%.

AutoMist: Automated Hood Cleaning on Your Schedule

AutoMist is an automated system that cleans the kitchen exhaust system daily without having to shut down operations.

“AutoMist runs while the restaurant is operating,” said Katie Dye, AutoMist Product Manager. “That is one of the reasons why AutoMist is a great fit for stores that are open 24 hours a day. They never have to shut down to clean their kitchen exhaust system.”

The automated cleaning takes place behind the baffle filters. Grease is washed out and collected in a container that is easy to empty daily, or directed to a floor drain with a grease trap. The detergent used in the system is easy to replace, food safe in its diluted form, safe to dispose of down the drain and has a triple zero hazmat rating, making it safe for employees to handle. Restaurant Technologies can eliminate or reduce the need for third-party hood cleaning while reducing risk from prolonged grease build-up and freeing up labor.

Tips to Make Your Exhaust Hood Easier to Clean

• Install duct access doors. This allows visibility to the ducts’ condition and allows easier access to clean them. 
• Install an exhaust fan access port. This is an NFPA 96 fire code requirement, but some restaurants still don’t have one. Easier access to the fan blades allows you to wash them more frequently, which prevents unbalanced fan blades and excess wear and tear, lengthening the life of the fan.
• Install an exhaust fan hinge kit. This allows cleaners to tip the fan back to gain access to the ductwork. This prevents damage to the fan base, fan components, and damage to your roof that can happen during cleaning.  
• Clean baffles/filters regularly. Even if you get the whole system cleaned and inspected often, your hood baffles or filters should be cleaned on a much more frequent basis. Refer to your hood filter manufacturer for more precise details.