The typical applications of Butterfly Valves are: Vacuum services, slurry services,
High temperature, high pressure and steam services, Compressed gas or air applications and cooling water,
gas, air and fire protection. Butterfly Valves are used to regulate and control, throttle the flow.

Popular Manufacturers:


Butterfly Valve Manufacturers:


  • Boving
  • English Electric
  • Tomoe
  • Keystone
  • Iprosa
  • Center Line
  • Vanessa

  • S&P (ENG) Ltd
  • Jamesbury
  • B. Controls
  • Leeds Valves
  • Winn
  • Flowseal
  • Winn

  • JVC
  • Dome
  • Blakeborough
  • Neles
  • Bray
  • Danfoss Solca
  • Ebro

  • Zwick
  • Hobbs
  • Fisher
  • Batley
  • Vanessa
  • Serck Audco
  • Introl



Leak Rates for Valves:


All valves are designed to meet a designated internal permissible leak rate standard (FCI/ANSI).  There are six (6) permissible leak rates or Classes numbered 1 through VI. The higher the leak rate number, the lower permissible internal leak rate.


  • Class I valve, will the highest internal leak rate and usually the lowest cost.
  • Class VI valve will have the lowest permissible internal leak rate therefore cost will increase.


Identifying the permissible internal leak rate for a valve has to be one of the top priorities when choosing the correct valve.  A valve with a high leak rate, will cause excessive wear. The valves with a high leak rate will internally pass more medium and result in premature valve failure.


There are six different seat leakage classifications as defined by ANSI FCI 70-2.


  • CLASS I: is also known as dust tight and can refer to metal or resilient seated valves.
  • CLASS IV: is also known as metal to metal. It is the kind of leakage rate you can expect from a valve with a metal shut-off disc and metal seat.
  • CLASS Vl: is known as a soft seat classification. Soft Seat Valves are those where the seat or shut-off disc or both are made from some kind of resilient material such as Teflon

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