What Are ANSI Valves?

ANSI valves are designed, manufactured and tested in accordance with the American National Standards Institute (ANSI) and related standards (e.g. API, ASME, etc.). Its core principles are the standardization of valves in North America and global industrial piping systems to ensure that valves meet internationally recognized requirements in terms of size, pressure class, materials, performance and test methods. Here's a closer look:
I. ANSI/ASMEB B16.34 Core Standard: specify valve pressure temperature class, flange connection dimensions and material requirements as basic criteria for valve design.
API Standards: such as API 6D (line valves), API 609 (butterfly valves), etc., to supplement technical details of a particular valve types. For example, API 6D requires valves to pass rigorous sealing and strength tests.
ASME Standards: such as ASME B16.5 (flange dimensions) and ASME B16.25 (butt-welded connection dimensions) to ensure compatibility of valve with piping systems.
ii. Core Features Pressure Rating Classification: Pressure Ranks are expressed as 150, 300, 600 pounds (grades) corresponding to different pressure-temperature combinations. For example, a Class 300 valve can withstand a pressure of approximately 5.0 MPa at room temperature.
Standardized Size: The standard diameter is designed to be in inches (e.g., 2 inches for DN50), ensuring seamless integration with ASTM piping systems and reducing installation compatibility issues.
Material and process Validation: Key materials include carbon steel (WCB), stainless steel (304/316L) and alloy steel and require material certification (e.g., ASTM standards) and process validation (e.g. welded nondestructive testing).
Strict performance test: shell strength tests (e.g. 300LB valve test at 11.3 MPa), sealing test (e.g., gas tightness test at 0.4 MPa -0.4-0.7 MPa) and function test (e.g., operational life tests) are required.
III. Typical Application Scenarios
Petrochemical Industry: Used in refining equipment and transnational oil and gas pipelines, required to be compatible with high temperature, high pressure, corrosive media (e.g. crude oil, refined oil). For example, a WCB carbon steel valve body + 300 pressure rated gate valve provides stable crude oil transportation.
Energy industry: gas turbine fuel pipelines and LNG terminal cryogenic pipelines requiring cryogenic properties (e.g., -196°C). For example, a 316L stainless steel valve body with a Class 600 cryogenic ball valve can safely transport LNG.
Shipbuilding industry: ballast water systems and fuel lines on ocean-going vessels must be resistant to corrosion and vibration. For example, a double-sided stainless steel body with a hard-sealed butterfly valve valve can operate steadily in marine environment for a long time.
Chemical industry: suitable for Sino-foreign joint venture chemical plants reactor feeder pipe, to prevent the leakage of weakly corrosive media. For example, a 316L stainless steel valve body with a PTFE soft seal gate valve can precisely control the flow of acid-base media.
IV. INTRODUCTION INTRODUCTION Introduction: Differences from National Standard Valves: Pressure rating: ANSI valves are classified by class (e.g. Class 150) and NSS valves by PN (e.g., PN16). Their pressure-temperature curves are different and not directly interchangeable.
Dimensions and Flange Specifications: ANSI valves nominal diameter (in inches), flange dimensions (in inches) in accordance with ANSIB16.5; Chinese standard valves nominal diameter mm, flange size (in inches) in accordance with GB/T9113. The two are incompatible.
Standard System Classification: ANSI valves are suitable for international piping systems (e.g. North American and Middle East projects), while Chinese standard valves mainly meet domestic engineering needs; additional certification is required for export projects.