As Clear As Grease

December 1, 2017 Emily Gamble

Grease management can be a daunting industry for newcomers, especially if it’s your first time trying to choose a system for your restaurant or project. And if you haven’t already, you’ll encounter a barrage of acronyms and seemingly complicated terms, like HGI, FOG, and interceptor. But don’t fret, because by the end of this post, you’ll be fluent in conversational grease-anese, and well on your way to selecting an ideal solution.

What the heck is a grease interceptor?

Traditional grease traps have been around for over a century, designed to keep FOG (fats, oils, and grease) from clogging up municipal sewer systems. Flourishing populations have resulted in more restaurants cooking more food, creating too much grease for septic tanks and treatment facilities to handle. We needed something larger, and more efficient to stop as much FOG as possible from reaching drain pipes and damaging the environment.

Enter grease interceptors: New technology, bigger capacities, tougher materials. According to the Uniform Plumbing Code (UPC), the main difference between a trap and an interceptor is how much liquid the device can effectively process in gallons per minute (GPM), with traps handling less than 50 GPM, and interceptors handling over 50 GPM. But their separation efficiency is where interceptors really shine.

So, small = trap, big = interceptor, right? Essentially, but some like to argue that only the products spawned by the heavy wave of industry innovations starting in 01’ are interceptors, while all previous designs are traps. And while that’s not intensely important, the different kinds of interceptors are.


HGI stands for hydromechanical grease interceptor, the current Cadillac of grease management technology (especially in terms of environmental effects). HGIs use a unique balance of air and water to continuously separate as much FOG (fats, oils, grease) from water as possible. HGIs are also classified by their interior baffles, which are engineered to slow the flow of grease into the interceptor, and maximize separation efficiency.


GGI stands for gravity grease interceptor, a somewhat simplified version of an HGI. GGIs are much larger than HGIs and contain a lot more water, which is why they are usually found both outdoors and underground. With no baffles, FOG flows uninhibited into one of at least two massive chambers, and is slowed only by the GGIs massive reservoir of water. Their engineering then relies only on time and the buoyancy of grease for separation.

Choosing the optimal interceptor is based on the needs, output, and budget of your application. Alternatively, you can always consult an industrial plumber to choose one for you, but with your freshly upgraded vocabulary, feel free to check out our sizing calculator or read more about sizing here.

Previous Article
Sizing Up Grease Interceptors
Sizing Up Grease Interceptors

Despite the lack of any actual cutting, the age old adage “measure twice and cut once” is intensely relevan...

Next Article
Endura® Shines at FOG Forum
Endura® Shines at FOG Forum

In April, the Western State Alliance (WSA), in collaboration with The Pacific Northwest Pollution Preventio...