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Engineering Parameters for Selecting Valve End Connections
Valve end connections define how a valve joins to piping systems. This article reviews common end connection types, and explains how each connection works, when to use it, and how pressure class, process medium, sealing, and installation influence selection.
• By Momenta Fire / QRC Valves
The selection of valve end connections should never be in isolation. They must align with piping design codes, process conditions, and the overall maintenance practises of the facility. Key engineering parameters include internal pressure, operating temperature, allowable leakage rate, mechanical loads, and inspection accessibility.
End connections must comply with the pressure and temperature limits defined by applicable standards such as ASME B16.5, the ASME B31 series, or EN 1092. At elevated pressures and temperatures, gasketed joints may experience relaxation, creep, or extrusion, while welded joints generally provide higher structural integrity.
The nature of the process fluid strongly affects connection selection. Hazardous, flammable, or toxic media typically require connections with minimal leak paths. In such cases, welded or metal-to-metal sealing connections are often preferred over threaded or gasket-dependent joints.
Piping systems impose axial, bending, and torsional loads on valve connections due to thermal expansion, vibration, and weight. Welded connections distribute stresses more uniformly, while flanged and wafer connections require careful bolt load management and pipe support to avoid misalignment.
End connections must comply with the pressure and temperature limits defined by applicable standards such as ASME B16.5, the ASME B31 series, or EN 1092.
Connections that allow easy disassembly are advantageous in systems requiring frequent inspection or valve replacement. Conversely, permanently welded connections are better for long-term installations with minimal intervention.
Types of Valve End Connections In industrial piping systems, the selection of valve end connections is a critical design consideration. The end connection not only determines how the valve integrates with the pipeline but also influences factors such as sealing integrity, ease of installation, maintenance requirements, and overall system reliability.
The most widely used valve end connections include:
Raised Face( RF) Flanged Connections Raised Face flanged connections rely on a gasket compressed between two raised sealing surfaces. The raised face concentrates bolt load onto a smaller gasket area, improving sealing efficiency compared to flat face designs.
Typical Applications: Raised Faced flanges are a mainstay in oil & gas, chemical processing, power generation, and general industrial piping. They are suitable for a broad range of pressure classes and temperatures when paired with the correct gasket material.
Raised Face flanges rely on a gasket that is compressed between two raised sealing surfaces.
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