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

• A. Master; Local
• B. Area; Master
• C. Master; Area
• D. Local; Master

Answer: (D)

In gas cylinder manifolds with multiple headers, it’s essential to warn staff both at the point of changeover and across the whole facility. The local signal near the manifold immediately alerts the operator to the changeover status, so the transition can be managed safely and without delay. At the same time, activating an indicator at all master alarm panels provides facility-wide visibility, letting central staff and other departments know when or just before a header swap occurs. This dual signaling supports coordinated control and helps prevent disruption of gas supply. Area alarm panels wouldn’t guarantee global awareness, whereas the combination of a local signal plus master alarm panel indicators best ensures prompt, comprehensive notification.