ISO 15848-1

Applies to: Industrial valves of all types for external leakage qualification (stem seals and body joints); three emission classes (A, B, CC1); four temperature classes (I: −29/+40 °C, II: −46/+200 °C, III: −46/+400 °C, IV: special); endurance classes CO1, CO2, EM1, EM2; used globally where EN/ISO regulatory framework applies.

Does NOT cover: Production acceptance testing of individual valves (ISO 15848-2 covers production test); control valves under IEC 60534-4; valve seat leakage (internal).

• Three emission classes measured in volume fraction: Class A ≤ 1×10⁻⁴ cm³/s·m, Class B ≤ 5×10⁻³ cm³/s·m, Class CC1 ≤ 5×10⁻² cm³/s·m
• Temperature class determines thermal cycling test range
• Endurance class determines number of mechanical cycles (CO1: 205 cycles, CO2: 1500 cycles, EM1: 20,000 cycles, EM2: 100,000 cycles)
• Test medium: helium or methane as agreed
• Leakage measurement using mass spectrometry or calibrated detector

ISO 15848-1 is the dominant international framework for valve fugitive emissions type testing, widely referenced in European, Middle Eastern, and Asian Pacific specifications. Its multi-dimensional classification system (emission class × temperature class × endurance class) provides greater specification precision than API 624/641, allowing engineers to match the valve certification exactly to the intended service conditions.

Engineering note: When comparing ISO 15848-1 and API 624/641 certifications, note that ISO uses a different leakage unit (cm³/s·m stem circumference) than API (ppm by volume). Class A in both systems is approximately equivalent for typical process valve stem sizes. For projects accepting either standard, specify the more stringent requirement to ensure compliance under both frameworks.