What is required for a manually fired fuse ignition system for aerial shells?

A manually fired fuse ignition system for aerial shells must incorporate a time delay extension, which allows for the safe ignition of the shells without requiring an immediate firing. This feature provides operators with a crucial advantage, enabling them time to retreat to a safe distance after igniting the fuse.

Utilizing a time delay also enhances safety, ensuring that the individual operating the fireworks display has sufficient time to clear the area and avoid potential hazards associated with premature ignition. This requirement aligns with safety practices outlined in NFPA 1123, which emphasizes the need for careful consideration of ignition timing and operator safety during a fireworks display.

In contrast, the other options do not align with the established regulations. For example, while remote ignition may increase safety, it is not the defining feature of manual systems in this context. Similarly, limitations on preloading or requirements for immediate ignition would conflict with the operational flexibility and safety protocols provided by the inclusion of a time delay extension. Thus, the choice highlighting the allowance for a time delay extension encapsulates a crucial aspect of safely managing fireworks displays.