7 Common Valve End Connections

1. Threaded Ends - Compact & Economical

Threaded connections join valves and pipes via mating male and female threads. They are a popular, low-cost, and space-saving solution for smaller lines.

  • Key Features: Ideal for small diameters (typically ≤DN50) and low-pressure applications. Common in instrumentation and general plumbing.
  • Thread Standards:
    • DN (Nominal Diameter): The standard dimension designation for pipes and valves.
    • G (BSPP Parallel Thread): Sealing requires thread seal tape or compound. The most common type for general water and air services.
    • NPT (Tapered Pipe Thread): The threads themselves form a mechanical seal as they tighten. Widely used in pressure piping systems in North America and the process industry.
  • Ideal For: Water, oil, and gas services in small-bore, non-hazardous piping. Most valves sold on our site feature threaded ends to meet general user needs.
  • Note: Risk of leakage under vibration; over-tightening can damage threads.

2. Flanged Ends - The Industrial Standard

Flanged connections use bolts to clamp two gasketed flanges together. This is the most versatile and widely used method in industrial piping.

  • Key Features: Robust, reliable sealing, and easy maintenance. Suitable for a vast range of sizes (from DN50 and up) and pressure ratings.
  • Face Types: Common types include Raised Face (RF), Flat Face (FF), and Ring-Type Joint (RTJ), which accommodate different gaskets for specific pressure classes.
  • Ideal For: Virtually all industrial sectors, including oil & gas, chemical, power, and water treatment.
  • Advantage: High degree of standardization, making components highly interchangeable.

3. Wafer / Lug Ends - Space-Saving Design

Wafer-style valves are designed to be clamped between two pipeline flanges with long bolts. Lug-style valves have threaded inserts, allowing them to be bolted directly to each flange without a through-bolt.

  • Key Features: The most compact and lightweight design, significantly reducing weight and installation space.
  • Typical Valves: Primarily used for butterfly valves and some check valves.
  • Ideal For: Systems where space and weight are critical, such as in ships, building services, and fire protection lines.
  • Note: Sealing relies entirely on the compressive force from the flange bolts.

4. Welded Ends - Maximum Reliability

Welded ends provide a permanent, leak-proof connection by fusing the valve directly to the pipe.

  • Key Features: Zero-leak integrity, superior strength, and excellent performance under high pressure and temperature cycling.
  • Welding Types:
    • Butt Weld (BW): Highest strength and fatigue resistance. Used in the most severe services (e.g., high-temperature steam, ethylene, nuclear).
    • Socket Weld (SW): Easier alignment and installation for small-bore piping.
  • Ideal For: Critical applications in power generation, nuclear, and chemical processing where leakage is unacceptable.
  • Disadvantage: Difficult to remove or repair, requiring cutting and re-welding.

5. Clamp Ends - Hygienic & Quick

Also known as Tri-Clamp connections, they use a clamp, a gasket, and two grooved ends to create a secure, seal.

  • Key Features: Instant connection and disassembly without tools. Smooth, crevice-free bore allows for easy cleaning and sterilization (CIP/SIP).
  • Ideal For: Industries with high hygiene standards, such as food & beverage, dairy, pharmaceutical, and biotech.
  • Advantage: The joint has some flexibility to handle minor misalignment and thermal expansion.

6. Compression Tube Fittings - For Instrumentation

Commonly known as "ferrule" or "tube" fittings (e.g., Swagelok®, Gyrolok), these create a strong mechanical grip on the tubing.

  • Key Features: Vibration-resistant, leak-tight, and reusable. Provides a robust seal for small-diameter tubing.
  • Ideal For: Instrumentation lines, hydraulic and pneumatic systems, and sample panels in refineries and chemical plants.
  • Advantage: Offers a significant upgrade over threaded connections for critical, leak-free control systems.

7. Union Ends - For Easy Maintenance (Solvent Socket)

Common in plastic valves, this connection combines a solvent-weld socket with a union nut for easy service.

  • Key Features: Simplifies maintenance. One end features a solvent-weld socket for a permanent, cemented joint to plastic pipe (e.g., PVC, CPVC). The other end has a union nut with a gasket.
  • Ideal For: Water treatment, chemical dosing, and industrial plumbing systems using plastic piping.
  • Advantage: Allows for valve removal without cutting the pipe, making it an excellent choice for systems requiring future maintenance.
Back to blog