Hidden Danger

by Katie Lee

Taking a closer look at the commercial kitchen grease we don’t see.

By Brian S. Smith, Ph.D.

Grease is an issue that restaurants have been struggling with since the first time fat was cooked. Grease can be seen, felt and smelled throughout the restaurant. Restaurants can get into a lot of trouble because of grease; it seems to be an issue that is never fully resolved. Grease control and the necessity of addressing it is something that is not generally understood. There are areas in the restaurant that even today are ignored — not just by the restaurant owners, managers and employees, but by the regulatory people responsible for the protection of property and the safety of people: fire marshals and other AHJ (Authorities Having Jurisdiction).

Let’s first look at the obvious grease issue restaurants must face: the grease trap. Most restaurants have a grease trap in the floor; some have in-ground interceptors that separate water from grease and other things put into our sewers and storm water systems. Ask someone who knows storm water or sewage about the damage grease can do to your systems; he or she will give you a dissertation on the subject. Grease is bad for our sewer and storm water systems. The EPA and other agencies have plenty of regulations regarding the grease that goes from the kitchen to the drain.

But what about the grease we don’t see? The grease that is aerosol and finds its way up through the hood exhaust system to our rooftops? Most people don’t understand that the hood system — from the kitchen to its external exit — is filled with grease aerosol when it is in use. That grease aerosol, when slowed down, hits the cool air when it exits, reforms and collects on the fan, and often on the roof.

When grease collects on and around the fan and makes it onto the roof, it becomes not only an environmental issue, but it becomes a safety concern. Grease is flammable. Grease is slippery. Grease is caustic, and grease is dirty. All of these pitfalls are detrimental to the long term viability of the restaurant and to people’s safety.

Grease can ignite at as little as 550 degrees. Imagine the damage a fire fueled by grease could cause! There are over 5,000 restaurant fires a year and most are caused by grease. If that grease accumulates through the duct or on the roof, the damages can be catastrophic.  

RFB 2 27 Article GraphicThe kitchen can be dangerous. Poor ventilation in the kitchen can cause an accumulation of grease in the kitchen, making the entire environment slippery. Who wants to fall in a kitchen? Similarly, a rooftop can become very slippery and dangerous due to rooftop grease.

Grease is acidic, and if it accumulates on the roof it will eventually eat through the roof and may cause the roof or connecting parts to fail. Grease can also damage other mechanical equipment on the roof. These issues pose both financial and safety liabilities for the restaurant.

Grease is dirty. How often do we see a grease trail, or what looks like a skid mark, running away from the fan unit and oozing its way down the roof? How about the trail of grease and other material coming from the garbage/grease dumpster area? These problems pose an additional concern: the visual turnoff. Visibility is the precursor to profits; when customers see this trail of filth on the roof, or coming from the garbage area, it can affect profits. How many customers are lost by this visible turnoff?

Repairing the damage done by grease that is not under control can be costly — much more expensive than the annual fee to manage the grease properly. There are grease solutions for every external issue you face in your restaurants. There are at least seven different types of rooftop grease containment systems available. Many have been around for a long time and the technology has not changed for those systems in 25 years.

There are newer systems on the market that take advantage of the latest technologies and provide “lifetime of fan” warranties; this ensures that you have a containment system matched correctly to the exhaust fan unit for your restaurant. Another important key is keeping your containment system off your roof. While on-the-roof systems can be effective, the liabilities and costs associated with these systems makes their technology out of date — not to mention they rarely offer “lifetime of fan” warranties.

You also have options for your garbage or grease dumpster areas. These areas need the same level of attention and pose some of the greatest financial risks to restaurants as they are often the most visible.

The best place to start your search is with your KEC or roof maintenance companies. These firms will know the requirements of your roof and KEC systems, ensuring that you match the correct grease containment system with your roof and exhaust system. If you employ a facilities maintenance company, it should be able to reach out to its vendors to ensure that whatever system is chosen will address all of the risks associated with external grease containment. Most of the manufacturers of these units employ engineers, and both Driploc and our company offer no-cost engineering support to the service providers solving external grease containment.

In the end, grease containment is the restaurant’s responsibility. Failure can result in fines, fires and damages that go beyond financial or property loss. People have lost their lives as a result of poor grease containment in restaurants. Containing grease and removing it is the most important step restaurants and their service companies can take to prevent such disasters from occurring.


— Brian S. Smith, Ph.D., is the managing partner at Elgin Illinois-based Omni Containment Systems. As an active member of IKECA (International Kitchen Exhaust Cleaning Association), Smith speaks regularly around the world on grease and NFPA96 issues facing restaurants and other food processing companies. Omni Containment Systems is the world’s largest manufacturer of NFPA96-compliant products and holds seven patents related to kitchen exhaust access and grease containment systems. Email the author at [email protected].

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