API 622

Applies to: Type testing of compression packing sets (rings, packing box components) for process valve stems for fugitive emissions qualification; covers flexible graphite, PTFE, and combination packing types; allows packing qualification independent of a specific valve body.

Does NOT cover: Complete valve type testing (use API 624 for rising-stem or API 641 for quarter-turn); production acceptance testing of packing sets; packing for non-process or utility service.

• Packing set composition and geometry fully documented
• 210-cycle mechanical endurance test
• Thermal conditioning at 200 °C (392 °F)
• Methane test gas at 1 bar(g) stem leakage measurement
• Emission class A (≤50 ppm) or B (≤100 ppm) limit
• Re-testing required after any reformulation of packing material
• Third-party laboratory testing with documented traceability

API 622 tests the packing assembly (rings plus packing box components) rather than the complete valve, allowing packing manufacturers to qualify packing sets that can then be installed in multiple valve body designs. This modular approach reduces the cost of maintaining fugitive-emissions compliance when valve bodies remain unchanged but packing materials need updating to meet tighter regulatory limits.

Engineering note: API 622 packing qualification is increasingly used in LDAR programs as the basis for "generic" packing approvals — a single API 622 Class A certificate covers any valve where that packing geometry fits the packing box dimensions. However, valve manufacturers who seek API 624/641 certification must test the complete assembled valve, so packing certification under API 622 alone does not substitute for API 624/641 valve-level type certification.