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 valves will have the highest internal leak rate and usually the lowest cost.
  • Class VI valves 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.