Partial stroke testing is an important element in the structure of procedures ensuring performance monitoring of isolating or ESD valves. Netherlocks FAITH device prevents the risk of valve crossing the preset threshold during the partial stroke test that may cause technology process interruption..

Ideal device for technical maintenance.

FAITH (Fail Action Integrity Test Handling) device is installed between the valve and actuator. During the partial stroke test the steel pins used for blocking enable the valve rotation at the testing preset angle only (for example, 20 degrees). This also enables to maintain the actuator during production. The device is available for both linear and rotary actuators.

  Testing without technology process interruption.

FAITH device enables testing without technology process interruption. This enables to test more frequently and with less labor and time expenditures that in turn will reduce the valve wear and ensure its proper operation. The international standards such as IEC61508 and IEC61511 suggest testing all ESD and HIPPS-valves on a regular basis.


FAITH device is installed between the valve and actuator and made customized based on their parameters. No additional fastener between actuator and valve is needed. FAITH device is equipped with two blocking pins (for actuators with torque >1000 Nm) for alignment of force. This enables to avoid damaging of valve and actuator seal during stem blocking when testing. The FAITH device structure is simple and reliable. Being easy-to-operate it is used as a standard device for regular testing.

Advantages of Netherlocks FAITH.

  • Simple and reliable mechanical design;
  • No complicated programs, fragile cables and necessity in interrupting technology process for testing are needed;
  • Inability of valve to cross the preset threshold ensured by means of mechanical valve stroke blocking devices;
  • Guaranteed safe testing on industrial facility;
  • Process shutdown prevention due to errors when testing;
  • Real testing rather than a low speed operation simulation;
  • Ideally suitable for maintenance, saves precious time;
    Warranty of testing results achievement. No test is interrupted;
  • Standard use of double pin to block the actuators with torque >1000 Nm;
  • No additional fasteners between the valve and actuator.