Use PDI-G101 to test-rate and select a hydromechanical grease interceptor

Steps

1. Confirm the current edition of PDI-G101 in force (the standard has been revised multiple times, including a 2017 revision expanding coverage to larger-capacity units) by checking pdionline.org or the referencing plumbing code before citing an edition year
2. Understand that G101 rates interceptors by the gallons-per-minute (GPM) flow at which the unit still removes the standard's required grease-removal efficiency threshold from the influent
3. For a single fixture, calculate its GPM discharge per the applicable plumbing code's fixture-flow tables; for multiple fixtures on one interceptor, either sum individual fixture capacities, apply the standard's diversity/simultaneous-use method, or use the maximum simultaneous-discharge approach described in the standard
4. Select the nearest PDI-rated interceptor size at or above the calculated GPM demand — do not round down
5. Confirm the interceptor's grease storage capacity (in pounds) and drain-down time basis, since these determine service life and cleaning frequency independent of the GPM rating
6. Cross-check that the selected model carries current third-party certification to PDI-G101 (or equivalent ASME A112.14.3/CSA B481) rather than relying on a manufacturer's uncertified sizing claim