What is two-step sizing for grease interceptors is a common question I am asked. Uniform Plumbing Code (UPC) sizes hydromechanical grease interceptors (HGI) by flow rate (pipe size) as shown in step 1 above. If you are using a 4" grease waste line on a project UPC would require a minimum 75 GPM HGI (2-minute drain time) such as the Schier GB3. The GB3 is a third-party certified 75 GPM HGI so code is satisfied, right?

Technically yes, but the shortcoming of stopping at step 1 is that it does not factor loading. Compare two similar restaurants, let's say they are similar in size, kitchen equipment, the number of meals served per day (let's say 300) but the difference is food type. Restaurant 1 is a sandwich shop and restaurant 2 is a bar and grille. Back to the GB3 that satisfied UPC. The GB3 is third-party certified to a maximum grease capacity of 175.6 lbs of grease separated and stored. The sandwich shop would be considered a category A in step 2 above and produce 0.005 lbs of grease per meal served. 300 meals served per day * 0.005 lbs per meal served = 1.5 lbs of grease produced per day. By comparison the bar and grill at 300 meals served per day * 0.0455 lbs per meal served = 13.65 lbs of grease produced per day.

See the problem with stopping at step 1? If the GB3 is used it will require maintenance every 117 days at the sandwich shop (175.6 capacity of GB3 / 1.5 lbs grease produced per day). The bar and grill every 12 days (175.6 / 13.65). Both are UPC compliant per step 1 but by not considering loading they yield two very different maintenance intervals. 

The solution? The Schier GB-250 is 100 GPM, satisfies step 1 as it's 75 GPM or larger but will separate and store 1,751 lbs or grease. By using a GB-250 in the bar and grill application we can match the maintenance interval of the sandwich shop. 1,751 lbs grease capacity / 13.65 lbs produced per day = 128 days between cleanings. 

That's the basic concept of the two step approach. To make this really easy Schier has an online sizing program Grease Monkey that will allow you to input all parameters of the job and give a recommendation. They even have a team that will pre-approve AHJ acceptance and it's free.

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With 510 gallons of capacity the GB-500 slots perfectly between the successful 275 gallon GB-250 and the new 1,010 gallon GB-1000. Available early 2019 the GB-500 is third-party certified to ASME A112.14.3-2018 to hold 3,048 lbs of grease. The GB-500 can be installed above or below grade and has a new riser system allowing up to burial depths of 8' (top of unit to grade). A few firsts for the GB-500 is also the new triple inlet and outlet design allowing for ultimate design ease as well as the Safety Star™ feature preventing accidental entry into the tank. More about the GB-500 can be found here >>

Striem describes some of their products as being rotomolded (rotationally molded) but what does that mean? Watch the Ripple Engineering Pressure-Cooled Rotomolding machine in action at Striem in Kansas City in the video above. More about how the machine works can be found at the Ripple Engineering website. 

I've been asked this same question many times and Ken Loucks of IW Consulting Service provides a great explanation. If you aren't part of his email list sign up.  Read more here >>

Introducing the GB-1000. That's right, 1,000 gallons of hydromechanical grease interceptor with a third-party performance certification proving it holds 6,547 lbs of grease! Don't take our word for it, have a look at the ASME test report. Why specify a large volume grease interceptor without knowing what it actually holds?  Click here for all the information including technical data package in PDF and DWG as well as Revit and CSI masterspec files.

Schier Products recently unveiled the latest version of their grease interceptor sizing service, Grease Monkey. Updates include the ability to create a profile and save jobs for future reference or use, the ability to do a quick sizing and a polished user interface that makes determining what product you need for your job easy. Grease Monkey uses Schier's grease production sizing method to determine real world demand based on volume and food type all while adhering to UPC guidelines. 

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The Junction in Bothell is the latest home to 9 of our GB-250 grease interceptors. The photo shown is 7 in series utilizing our no-charge H20 rated pickable cast iron cover option making servicing fast. This setup allows for 165,538 high grease producing meals before needing to be serviced. How do we do this? All Schier units are third-party certified to maximum grease capacity, in this case 1,076 lbs of grease per GB-250. Using Schier’s Grease Production Sizing Method (now included in the ASPE handbook) with each meal contributing 0.0455 lbs or grease this system will support 1,839 meals per day from the contributing common grease line all while retaining a 90 day cleaning interval insuring low run costs for tenants.

Why guess on what size interceptor is needed? Let us know if we can help with a sizing.