What is the maximum number of heads allowed on branch lines on either side of a cross main in a light hazard area?

In light hazard areas, the standards for the maximum number of sprinkler heads allowed on branch lines on either side of a cross main are established to ensure effective fire suppression while maintaining adequate water distribution. The correct answer indicates that a maximum of 8 heads may be installed on branch lines extending from a cross main in these types of environments.

The reason for this limit is tied to the requirements outlined in the National Fire Protection Association (NFPA) standards, specifically NFPA 13, which governs the design and installation of sprinkler systems. This regulation considers factors such as the water supply availability, the hydraulic calculations necessary to determine the effectiveness of the system, and the spacing needed for sufficient coverage as defined by the hazard classification.

In light hazard areas, controlling the number of heads per branch line is important because it influences the amount of water each head can deliver. Having too many heads can dilute the pressure and flow available to each sprinkler, potentially compromising their ability to effectively extinguish a fire. By capping the number of heads at 8, the design aims to maintain optimal performance, ensuring that sprinkler coverage is both sufficient and efficient to handle potential fire scenarios typical in light hazard conditions.

This knowledge is crucial for sprinkler fitters as it underscores the importance of