Manifolds for gas cylinders shall actuate a ______ signal and shall activate an indicator at all ______ alarm panels to indicate when or just before changeover from one header to the other.

• A. local - master
• B. master - area
• C. area - master
• D. master - local

Answer: (A)

The changeover event needs two levels of indication: an immediate, on-site cue and a facility-wide alert. A local signal from the manifold provides that immediate feedback right at the source, so operators know exactly when the header is switching or about to switch. At the same time, activating an indicator at all master alarm panels ensures staff throughout the building are aware of the changeover status, allowing timely response if needed. This combination—local signal for the point of use and master alarm panels for the area-wide alert—best matches the requirement, making the pair local signal and master alarm panels.