Which term is described by the stop valve locked shut symbol?

• A. Stop valve locked shut
• B. Stop valve
• C. Stop valve locked open
• D. Swing check valve

Answer: (A)

Understanding valve status and lockout indicators helps ensure safe isolation of piping systems. The symbol described communicates a stop valve that has been secured in the closed position, typically with a locking device like a padlock. This means the valve cannot be opened until the lock is removed, which is essential during maintenance or whenever isolation is required for safety. A plain stop valve symbol would only indicate the valve itself, not its locked state. A symbol showing a stop valve locked open would convey the opposite condition, meaning the valve is secured in the open position. A swing check valve is a different type of valve and has its own distinct symbol.