Which SOPV can only be secured locally on stations?

Which SOPV can only be secured locally on stations?

• A. None
• B. Master
• C. Group
• D. Both

Answer: (B)

In this system, the main isolation point is the Master SOPV. It sits at the station and governs flow to the entire transfer area, so its securement must be verified and applied directly at the site by the on‑scene operator. Locking the Master valve locally ensures a positive, verifiable isolation that cannot be overridden from a distant control point. The other valves (Group and Local) are designed to be secured through different control or interlock arrangements, not restricted to on-site securing. Therefore, the only SOPV that can be secured locally on stations is the Master.

In this system, the main isolation point is the Master SOPV. It sits at the station and governs flow to the entire transfer area, so its securement must be verified and applied directly at the site by the on‑scene operator. Locking the Master valve locally ensures a positive, verifiable isolation that cannot be overridden from a distant control point. The other valves (Group and Local) are designed to be secured through different control or interlock arrangements, not restricted to on-site securing. Therefore, the only SOPV that can be secured locally on stations is the Master.