There’s Grease On My Roof?

Understanding the need for rooftop grease containment.

By Greg Stark

For anyone that has ever gone up the ladder in your kitchen or utility room to the rooftop, you already know there is always something new to discover, maintain or fix. With so much equipment sitting out of sight, it is easy to forget the amount of equipment sitting on the rooftop. This includes everything from packaged heating and air conditioning, chillers, satellite dishes, drains, ventilation fans and exhaust equipment. All of this equipment is required to keep your business open and running smoothly, and each one requires its own level of maintenance. Today we are going to dive into the little-known world of FOGs (fats, oils and greases) that are discharged from the exhaust fans located above your kitchen’s hood system. Yes, you read that correctly: The grease from that delicious steak or hamburger is actually draining out onto your rooftop and causing all sorts of short term and long term issues for your rooftop investments.

During the standard cooking process on a flat top, char grill or wood burning cooking surface, hundreds of degrees of heat are cooking items for customers. As these foods heat, the FOGs are slowly burned off and put into the air. This airborne particulate is largely drawn into your hood system directly above these cooking systems thanks to an exhaust fan on the roof acting like a giant vacuum. At this point, your hood filters do a great job creating the extra surface area and fire protection to absorb some of this particulate. However, slowly but surely, FOGs make their way into your ductwork and cool, solidify and build up over time. As grease is fuel to a fire, it is legally required in almost all cases to get your kitchen exhaust system cleaned by a professional contractor. This is often referred to as your KEC (Kitchen Exhaust Cleaning) company. You may also have a contractor who offers soak tanks to clean your hood filters.

Here is where it gets interesting. Between exhaust cleanings, some of the FOGs have actually made it all the way to the exhaust fan and have begun leaking from a spout or drain on the fan itself onto your rooftop. Once there, these FOGs can present numerous problems:

1. The FOGs are slightly acidic and thus will slowly eat away at your roof membranes, causing damage and, ultimately, costly repairs. Not to mention leaks in your restaurant and a voided roof warranty!

2. Fats, oils and greases are potential fuel for a fire. Fuel in your exhaust system and on your roof will cause the fire to spread faster, thus causing more damage. This can be especially hazardous in strip centers, malls or any shared tenant spaces.

3. Storm drains are not designed to handle grease. This is why you learned as a child not to pour the bacon grease in the sink. As it cools and solidifies, it clogs storm drains and prevents the proper flow of water. There are strict laws in place in most places to prevent this from happening, and these laws have high daily fines while the mess is being cleaned up.

4. Plants and animals are not built to withstand the acids contained in FOGs. If left untreated, these greases will destroy your beautiful landscaping and leave deceased animals on your rooftop. None of this is sanitary or the image you want customers to see.

5. FOGs are just the kind of slippery substance we don’t want on an elevated roof deck. This leaves potential for a contractor getting grease on their work boots and climbing down a ladder. Which further leads to the potential of severe injury or death from slipping and falling. To make matters worse, compensation claims and liability cases could leave a huge impact on your bottom line.

These are very serious risks that ultimately need a solution to prevent them. Enter rooftop grease containment. There are many contractors, manufacturers and distributors who offer solutions to this problem. These solutions are typically products that are built in or around the exhaust system to prevent the grease from ever touching the roof deck in the first place. However, containing FOGs is just the beginning of the issues these rooftop guardians must fight against, and not all rooftop grease containment systems are created equal. As it turns out, absorption of these contaminants is a bigger task then you think. There are a lot of variables at play. You must make sure a rooftop grease containment system meets these requirements:

1. Obviously, it must absorb fats, oils and greases. The more the merrier. This is typically done with a sorbent material much like a napkin or paper towel, but on a more robust, industrial scale. Containment capacity is a vital measurement in your rooftop grease containment needs. How much grease are you producing? How much do you need to absorb on the rooftop? Can my grease containment system meet that expectation? Most providers of rooftop grease containment have multiple models, sizes and capacities to choose from, ranging in price of course.

2. A good containment system will manage the elements just as well as — if not better than — grease. With exposure to the outside world, the system will need to endure water, wind, falling debris, and everything else mother nature can throw at it. If the grease is just going to mix with the rain water and run down the drain, then it isn’t very effective. Good containment systems are made of hydrophobic (water resistant) materials. If there are 60 mph wind gusts, the containment system can’t fly away. Good containment systems are either attached directly to the fan curb or are very low profile to prevent these issues.

3. It cannot turn into a literal fuel tank. The only thing worse than a fire spreading across the rooftop riding a trail of grease is a large quantity of grease centered around the fire source in a nice big containment system. A good containment system will address the needs of fire suppression, control and prevention. Make sure this is addressed when sourcing a rooftop grease containment provider.

4. Installation of containment systems can be a messy business. In most cases beyond new build-outs, cleanup of the current grease must be considered. This will usually require a contractor, likely your exhaust cleaner, to clean up the grease on the rooftop currently. Depending on how long the grease has been baking in the sun, removal of this fried rooftop grease can reveal or even cause damage. It is important that you are prepared to have a roofing inspection completed along with your cleanup or shortly after. If you have a warranty in place, this should be completed by the original installer. You should call the installer of your roof system for clarification.

5. ALL rooftop grease containments require care and maintenance. Most grease containment systems use a series of filters to absorb FOGs. Once these filters reach their capacity, they will need to be replaced. In many cases, you will have to use a different contractor than the original equipment manufacturer. There are containment companies that offer service along with their products, though, and this should be asked about when considering rooftop containment. It should also be noted that containment maintenance is an ongoing process. As long as you are cooking, you will need containment service.

6. Additionally, during kitchen exhaust cleanings, the containment systems will need to be covered. This is because the chemicals used to clean your exhaust system are usually oil-based, and if those cleaning chemicals touch your containment, they will be absorbed into the system. This is a waste of your system’s filters. Most containment providers also clean exhaust systems, but if they don’t, it is recommended that you put them in touch with your containment provider to ensure this due care is given.

7. In most kitchen hood systems, you will have different cooking equipment being covered. You may also have different exhaust fans on the rooftop to meet different air flow needs. Due to these variables, your containment systems must be adjusted accordingly. Your rooftop may need more than one containment system and require to different models to ensure everything is collected properly. When sourcing a containment provider, it is good to have pictures ready so the proper solution can be provided. If you are getting containment before a new location opens, it is good to put your containment provider in touch with the main General Contractor (GC) doing the work so mechanical drawings can be considered.

With these variables to consider, rooftop grease containment is not only vital to your operation, but may require additional assistance to procure, install and maintain. However, enjoying a grease-free rooftop provides a peace of mind that your rooftop investments are secured, even when the grill and your dining area are nice and full. As FOGs on rooftops become ever more prevalent, it is those who know about rooftop grease who have the responsibility to act with the intelligence and diligence to ensure guests, investments and the environment are safe.

— Greg Stark is marketing director of Naperville, Illinois-based Grease Guard LLC, dba Rooftop Solutions. Stark has been in the rooftop grease containment industry since 2009 and continues to work diligently toward helping building owners protect their rooftop investments. Email the author at greg.stark@greaseguard.com.