Valve Car Seals on Safety Critical Valves

Car seals in different colors

Car seals are simple locking devices (such as a steel cable strand or a plastic tie) used to “lock” (or seal) safety critical valves in a predetermined “safe position” (either “open”, “close” or an identified middle position).
Once a car seal is used, the valve position can only be changed by cutting and opening the car seal. (then this will indicate a possible tampering, or an authorized change).

Color coding of the car seal devices are sometimes used to easily identify the valve position (e.g. red for closed, green for open).

Car seal requirements on identified safety critical valves should be shown on respective P&IDs. (for examples: valves on a fire water mains line). Following notations are generally used with respective valves.

CSO – car seal is required at open position

CSC – car seal is required at closed position

Car seal put on a Valve's hand wheel