As a leading valve distributor, API fugitive emission standards are something MRC Global addresses on a daily basis. Compliance with these standards and the associated EPA standards are a vital part of the valve selection and sourcing process.
Until recent American Petroleum Institute (API) measures were put into place, the US Clean Air Act of 1963, the Air Quality Act of 1967, the Clean Air Act Extension in 1970, Clean Air Act Amendments in 1977 and 1990, and the US Environmental Protection Agency (EPA) Method 21 were used to qualify valve fugitive emissions. Since 1963, the EPA and API testing requirements have been the most common industry standards for measuring fugitive emissions on valves. They are constantly being updated and improved, and if end users do not comply with EPA standards, they can face both monetary and safety repercussions.
For this blog, I will describe fugitive emissions as any leakage through any pressure barrier in a valve, however, the valve packing is usually the focal point for fugitive emission conversations. Keeping in mind that approximately 60% of all fugitive emissions from a plant originate from valves, I will focus on the testing and requirements for the packing and packing area of the valve, which is the most common source of escaped fugitive emissions.
API 622 Second Edition
In 2011, API 622 Second Edition was published. This standard was designed to provide a clear roadmap for packing qualifications, while giving the end users confidence in the product they are buying and installing. It is strictly a standard for testing packing, and was not specific to a valve.
This testing is strictly defined. Any packing manufacturer that states that they comply with API 622 must pass this test when done by third party testing labs. The test consists of a standardized test fixture, not a valve. This test fixture has very specific requirements regarding bore finishes, lengths and shaft finishes, providing standardization and equality for every manufacturer. Also, this fixture assures that, regardless of the testing lab, no single packing manufacturer has any advantage during the test.
The packing is installed in this fixture and undergoes testing using dry methane gas as a test media. The test lasts for 5 days with 150 cycles at ambient temperature each day and 150 cycles at 500° F, both at 600 PSIG, for a total of 1,510 cycles with only 10 cycles at the end of the test at ambient temperature.
The maximum allowable leakage at any time during the test is 100 parts per million (PPM), using a detection probe.
In 2014, API 624 was published and is applicable for rising stem valves only. It is strictly a standard for testing valves, utilizing packing that has previously passed the API 622 standard, and, therefore, the maximum allowable fugitive emissions would be 100 PPM using a detection probe. This testing can be performed either internally or by a third party. Gate and globe valves, which are both rising stem valves, represent a high percentage of installed valves throughout most operating plants, so this standard is important for most of our downstream customers.
This test, using dry methane gas as a test media, lasts for 3 days with 50 cycles at ambient temperature each day and 50 cycles at 500° F, both at 600 PSIG or the maximum pressure allowable for valve rating at this temperature per ASME B16.34, with 10 cycles at ambient temperature, for a total of 310 cycles.
Again, if the detected leakage at any time during the test exceeded the 100 PPM allowance, the valve does not pass and the entire test must be re-done.
API 641 was published in 2016 to address fugitive emissions in quarter turn valves. Defining a standard for fugitive emission levels for quarter turn valves was more difficult, due to various packing materials that are utilized throughout the industry. The scope of this standard includes valves < NPS 24” and pressure classes < ASME B16.34 class 1500. This scope could also fall into one of six Groups; A, B, or C based upon max pressure rating at 500 F, or D, E, or F based on max pressure rating at < 500 F. This test using dry methane gas as the test media, consist of 3 thermal cycles beginning at ambient going to high temperature, then back to ambient defined as one thermal cycle. 100 mechanical cycles at each ambient and high temp level is required, with a final 10 mechanical cycles at ambient to end the test, for a total of 610 cycles. Leakage cannot exceed 100 PPM. This test could include Ball, Plug, Butterfly, and Check type valves.
If you are unsure about what standards your application requires, please contact us. One of our valve experts around the world would be happy to help you find the best and most cost effective solution for your situation.
About the Author
Ralph Chaney has been with MRC Global since 2009. Prior to joining our company, he worked in both the control valve and isolation valve arenas on the manufacturer side of the business. In his current role as Executive Director – Downstream Valves, Ralph continues to do what he has spent his entire 40+ year career doing every day – solving problems for customers, one order at a time.