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Grease Interceptor Sizing Simulator

PDI G-101 · UPC 1014 · IPC / EPA Gravity Method

When to use: Commercial kitchens, restaurants, and food-service facilities must intercept fats, oils & grease (FOG) before discharge to the sanitary sewer. Hydromechanical (HGI) units are sized by flow (GPM) from fixture drainage load per PDI G-101 / UPC 1014. Gravity (GGI) in-ground tanks are sized by liquid volume (gallons) from meals served per the EPA / IPC formula. Choose the method that matches your jurisdiction and installation.

Connected Fixtures
25 gal ea
qty
50 gal ea
qty
75 gal ea
qty
100 gal ea
qty
15 gal ea
qty
10 gal ea
qty
20 gal ea
qty
Method
Required GPM = (Σ fixture volume × 0.75 drainage-load factor) ÷ 1-min drainage period. Result rounded up to next PDI standard rating.
Required Interceptor Rating
100
GPM (PDI standard)
Results
Total Fixture Volume130 gal
Calculated Required Flow97.5 GPM
Selected PDI Rating100 GPM
Grease Retention (UPC 1014.3)200 lb
Fixture Volume Breakdown
1 × 3-Compartment Sink75 gal
1 × Mop / Service Sink15 gal
2 × Floor Drain20 gal
1 × Pre-Rinse Station20 gal
Code References & Notes
PDI G-101 — Hydromechanical grease interceptor flow ratings & testing
UPC §1014 / Table 1014.3 — Grease retention = 2 lb per GPM of rating
IPC §1003.3 / EPA 1032 — Gravity interceptor volume by meals served
Locate HGI close to fixtures; install flow-control fitting per rating
Always verify local AHJ amendments — sizing requirements vary by jurisdiction