Valve Fugitive Emission Standards: ISO 15848 and API 622

Fugitive emissions from valve packing are a significant source of VOC and greenhouse gas releases at process plants. ISO 15848 and API 622 define test methods and acceptance criteria for qualifying valve packing and valves for low fugitive emission service.

ISO 15848 Overview

ISO 15848-1 classifies valves by tightness class (A, B, C) and endurance class (CO1, CO2). Class A is the most stringent at 50 ppm methane equivalent leakage. The test protocol includes thermal cycling, mechanical cycling, and leakage measurement by sniffing probe or vacuum enclosure.

API 622 Packing Test

API 622 evaluates packing rings independently of the valve, cycling the packing 1510 times under methane gas at 1000 psi. Acceptance requires leakage below 100 ppm. Packing systems passing API 622 are used by operators as an approved materials list for fugitive emission control programs.

API 624 extends API 622 to complete valves with packing and stem sealISO 15848-2 covers in-production testing for quality assuranceFugitive emission tags identify valves qualified to specific standardsLDAR (Leak Detection and Repair) programs monitor emission compliance

Design Features for Low Emissions

Live-loaded packing systems, graphite-based packing, polished valve stems, and reduced stem clearance all contribute to lower fugitive emissions. Double packing with a lantern ring and venting capability allows collection and incineration of packing leakage.

Specify ISO 15848 Class A for toxic or odorous serviceMaintain packing gland load within manufacturer specificationInspect and adjust packing at each planned outageReplace packing that exceeds plant LDAR action levels immediately