Two different states
A valve's normal position (normally open, NO, or normally closed, NC) describes how it sits during normal operation. Its failure position describes where the actuator drives it if the signal, air or power is lost: fail open (FO), fail closed (FC) or fail last / in place (FL).
The two are independent. A valve can be normally open and fail closed, or normally closed and fail open. Mixing them up on a drawing is a common source of confusion during reviews.
How it is shown
InduDraft draws the failure position as an arrow on the valve stem and lets you set normal position separately. Your company specification may prefer text labels such as FC or FO next to the valve; check it before issuing drawings.
Which failure position a valve needs depends on the actuator arrangement and the process safety requirements. That decision belongs to the process and safety design, not to the drawing; this guide only covers notation.
Pneumatic control valve
FV-101 · FC
Try a control valve in InduDraft
Place a control valve and set actuator, normal position and failure position in the right panel.
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