What is the difference between API 598 and API 609

1. Definition and Scope of Application

API 609: Specifically pertains to the design, material, and manufacturing standards for Wafer Type Butterfly Valves, regulating the structure of double flange, lug type, Wafer Type Butterfly Valve length, flange connection size, and material requirements (such as CF8, CF8M stainless steel, etc.).

API 598: General valve inspection and testing standards for gate valves, ball valves, butterfly valves, and other valves, including pressure testing (shell strength, sealing performance, etc.), without limiting the type of valve.

2. the difference between the technical requirements

Content focus

API 609: butterfly valve structural design (such as three eccentric multi-level sealing structure), material selection (valve body, butterfly plate material, etc.) and flange connection standards (). (need to comply with ASME B16.5).

API 598: Specifies the valve test methods, including hydrostatic testing, air tightness testing, and leakage rate standards (such as allowable leakage).

Test Requirements

API 609 Butterfly valves are required to be tested according to API 598 (e.g., pressure testing, sealing verification), but API 609 itself does not contain specific test methods.

API 598 has more specific requirements for test media (water or air), test time (e.g., 1-2 minutes for shell strength testing), and leakage rate, and is applicable to all valve types.

3. Application Scenarios and Complementarity

API 609 serves as the basis for the design and manufacture of butterfly valves to ensure that the product meets the dimensional, material, and performance specifications.

API 598 serves as the basis for quality verification of valves before leaving the factory, used to confirm that the valve meets the safety and sealing requirements.

The two need to be used in conjunction: API 609 butterfly valves need to pass API 598 testing in order to be certified.

4. Examples of differences