Grease Production Sizing™
Schier recommends the Grease Production Sizing method for product selection: first by flow rate, then by grease capacity for pump-out cycle. Please note that our sizing method may not satisfy local jurisdiction requirements for installation approval. Always review plumbing code and locally adopted ordinances. Call us for help determining specific local requirements.
Step 1: size by flow rate
Hydromechanical Grease Interceptor Sizing Using Gravity Flow Rates (Per Ch. 10 of the Uniform Plumbing Code)
Diameter of Grease Waste Pipe Maximum Full Pipe Flow* Size of Grease Interceptor
One-minute Drainage Period Two-minute Drainage Period
2" 20 GPM 20 GPM 10 GPM
3" 60 GPM 75 GPM 35 GPM
4" 125 GPM 150 GPM 75 GPM
5" 230 GPM 250 GPM 125 GPM
6" 375 GPM 500 GPM 250 GPM
*¼inch slope per foot (20.8mm/m) based on Manning’s formula with friction factor N = 0.012.
Step 2: calculate grease capacity
Meals Per Day × Grease Production Values (see A through F below) × Days Per Pump-out Cycle = Grease Capacity Needed
Meals Per Day
Grease Production Values (see A through F below)
Days Per Pump-out Cycle
Grease Capacity Needed
category grease production values description / examples
Low Grease Production A0.005 lbs / meal (no flatware) serves food prepared offsite or food that requires minimal preparation and/or warming; sandwich shop, convenience store (no kitchen), hotel breakfast bar, frozen yogurt, coffee shop, take & bake pizza, bar (limited food service), cafeteria (no prep), grocery meat department, sushi (no grill)
B0.0065 lbs / meal (with flatware)
Medium Grease Production C0.025 lbs / meal (no flatware) serves foods from a limited menu and/or with a limited amount of onsite preparation; pizza, ice cream parlor, fast food hamburger (pre-cooked), caterer, Greek, Japanese, Vietnamese (Pho), grocery store (no fryer), cafeteria (limited prep), low category restaurants w/ fryer
D0.0325 lbs / meal (with flatware)
High Grease Production E0.035 lbs / meal (no flatware) serves a full menu of food prepared onsite; American traditional, hamburger (with grill), BBQ, Mexican, Italian, steak/seafood house, hibachi, buffet, fast food fried chicken, bakery/donut shop (w/fryer), Chinese, Indian, grocery store (w/ fryer), cafeteria (full prep), medium category restaurants w/ fryer
F0.0455 lbs / meal (with flatware)