Views: 0 Author: J-VALVES Publish Time: 2025-02-24 Origin: Site
Overview of API 6D and ISO 15848 Standards
API 6D, titled "Specification for Pipeline and Pipeline-Related Valves," is a widely recognized standard developed by the American Petroleum Institute. It provides comprehensive guidelines for the design, manufacturing, testing, and certification of pipeline valves, including check valves. The primary focus of API 6D is to ensure that valves meet specific requirements for durability, reliability, and safety in pipeline systems. Key aspects of API 6D include:
• Design and Construction: API 6D specifies detailed requirements for the materials, design, and construction of valves to ensure they can withstand the pressures and temperatures typical of pipeline operations.
• Testing: The standard mandates rigorous testing procedures to verify the performance of valves, including hydrostatic testing, functional testing, and fire testing to ensure the valve's integrity in emergency situations.
• Sealing Performance: API 6D emphasizes the importance of zero leakage under normal operating conditions and requires valves to undergo stringent testing to ensure they meet these requirements.
ISO 15848, titled "Industrial valves-Measurement, test and qualification procedures for fugitive emissions," is an international standard developed by the International Organization for Standardization. This standard focuses specifically on the measurement and qualification of fugitive emissions from valves, aiming to minimize environmental impact and ensure safety in industrial applications. Key aspects of ISO 15848 include:
• Type Testing: ISO 15848 Part 1 outlines detailed type testing procedures to evaluate the fugitive emission performance of valves. This includes mechanical cycling, thermal cycling, and leakage rate measurements.
• Production Testing: ISO 15848 Part 2 addresses the testing of production valves to ensure consistency with the type-tested performance.
• Sealing Performance: The standard provides a classification system for sealing performance, with different levels of acceptable leakage rates for valve stem and body seals.
Sealing Performance Comparison
• API 6D: API 6D requires valves to undergo a series of tests to ensure zero leakage under normal operating conditions. This includes hydrostatic testing at 1.5 times the maximum allowable working pressure (MAWP) and functional testing to verify proper operation. The standard also mandates fire testing to ensure the valve's integrity in emergency situations.
• ISO 15848: ISO 15848 focuses on fugitive emissions and classifies valves based on their leakage rates. The standard defines three primary sealing classes for valve stem and body seals:
• Class A (AH for helium, AM for methane): The highest sealing performance with minimal leakage.
• Class B (BH for helium, BM for methane): Moderate sealing performance with allowable leakage rates.
• Class C (CH for helium, CM for methane): Lower sealing performance with higher allowable leakage rates.
• API 6D: Testing under API 6D involves hydrostatic testing, functional testing, and fire testing. Hydrostatic testing is conducted at 1.5 times the MAWP to ensure the valve can withstand overpressure conditions. Functional testing verifies that the valve operates correctly and seals effectively. Fire testing evaluates the valve's ability to maintain integrity and prevent leakage during a fire.
• ISO 15848: Testing under ISO 15848 involves mechanical cycling, thermal cycling, and leakage rate measurements. Mechanical cycling tests the valve's durability over a specified number of cycles (e.g., 10,000 cycles for Class CO3). Thermal cycling exposes the valve to extreme temperature variations to assess its performance under thermal stress. Leakage rate measurements are conducted using helium or methane to determine the valve's fugitive emission performance.
Sealing Performance in Practice
• API 6D: Valves certified under API 6D are designed to provide zero leakage under normal operating conditions. This is achieved through rigorous testing and the use of high-quality materials and manufacturing processes. The standard ensures that valves can withstand the pressures and temperatures typical of pipeline operations without compromising their sealing performance.
• ISO 15848: Valves certified under ISO 15848 are classified based on their leakage rates. While Class A valves offer the highest sealing performance, even Class B and C valves are designed to minimize fugitive emissions. The standard's focus on fugitive emissions ensures that valves meet environmental and safety requirements, particularly in applications where volatile organic compounds (VOCs) are present.
