NFPA 72 requires a minimum separation for a Class A circuit's outbound and return paths. What is the minimum separation for a loop running horizontally in a hallway that is 9 feet wide?

In designing fire alarm systems, NFPA 72 emphasizes the significance of installing Class A circuits with proper separation between their outbound and return paths to mitigate the risk of short circuits or interference that could lead to system failures. For a loop running horizontally in a hallway that is 9 feet wide, the minimum separation requirement is established to ensure that any fault affecting one path does not impact the reliability of the alternate path.

The correct answer, which indicates a minimum separation of 4 feet, is derived from guidelines aimed at adhering to safety and operational integrity. NFPA 72 provides specifications to enhance system performance, and maintaining this level of separation is essential in environments where physical disturbances or wiring congestion may occur.

This requirement helps to ensure that both paths of the loop can function properly, maintaining effective communication within the fire alarm system. It is also crucial in terms of safety—if one path were to become compromised, having a sufficient distance reduces the likelihood of a simultaneous failure in the alternate path, ultimately contributing to the overall effectiveness and reliability of the alarm system.

In this context, maintaining 4 feet of separation meets the standard recommended in NFPA 72 for such installations in hallways, thereby providing the necessary protection for the fire alarm system.