The Best API Flush Plans for Fugitive Emissions: Ranked

Last update: 5/2/2026

Fugitive emissions are no longer just a maintenance nightmare, they are a significant financial and legal liability that threatens worker safety and operational efficiency. In an era of tightening EPA Leak Detection and Repair (LDAR) regulations and ambitious ESG goals, these “silent” leaks of VOCs and hazardous gases represent substantial product loss and environmental harm. Most major ESG reporting frameworks, including the GRI and SASB, now explicitly require companies to disclose fugitive emissions as a core part of their Scope 1 inventory. Because mechanical seals are a primary leak point, selecting an optimized API seal support system is the most critical lever for chemical facilities to satisfy these rigorous transparency standards while protecting their personnel.

We’ve ranked the API flush plans that detect and/or contain leakage from mechanical seals. Rankings are “good”, “better” or “best”, as defined below. While fluid pumping applications vary drastically and fugitive emissions can take the form of vapors or liquids, the intent of this article is to rank the flush plan technology and operating philosophy, including how well seal leakage is contained. Single seals, while not ideal for containing or preventing fugitive emissions, can be tolerable in certain applications and facilities. One of the best options for leakage containment is a dual pressurized seal which prevents and often eliminates leakage to atmosphere, keeping the pumped fluids within the pump, seal and seal support system.

Definitions of Rankings:

“Good” – Single seals with detection and alarms

“Better” – Dual unpressurized (“tandem”) seals with applicable flush plans

“Best” – Dual pressurized (“double”) seals with applicable flush plans