Basic Concept
Low Emission Valves refer to valves that, through special design and manufacturing processes of the stem packing and mid-seat gasket, control the leakage of media (gases, liquids) to extremely low levels. They are primarily used in industrial scenarios with high safety and environmental protection requirements. The core objective is to reduce or prevent the leakage of harmful media (such as volatile organic compounds (VOCs), toxic gases, flammable and explosive substances, etc.) into the external environment. Therefore, low emission valves offer multiple advantages in terms of energy conservation, emission reduction, reduced safety risks, and environmental pollution.
Key Technical Standards and Leakage Grades
The performance of Low Emission Valves is quantified by their leakage rate, and different industries follow different standards. Common standards include:
1. International Standards
ISO 15848-1: This standard classifies valve leakage grades into four levels: A (the highest requirement), B, C, and D. Grade A requires a leakage rate of ≤100 ppm (by volume).
API 624 (American Petroleum Institute): This standard, applicable to the refining and chemical industries, specifies a leakage rate of ≤100 ppm (for gases) under specific pressures.
EPA Standard (U.S. Environmental Protection Agency): This standard, targeting VOC emissions, requires a leakage rate of ≤500 ppm.
2. Chinese Standards
GB/T 42223-2022: This standard, which references international standards, regulates the design, manufacturing, and testing of Low Emission Valves.