What defines a system demand in NFPA 13?

A system demand in NFPA 13 is defined as the calculated flow and pressure required from the water supply to ensure that the sprinkler system can function effectively during a fire event. This demand is critical as it ensures that the system is designed to deliver the necessary water at adequate pressure to suppress a fire based on the specific hazard and occupancy classifications.

To accurately determine the system demand, engineers must consider various factors including the number of sprinklers that will activate, their location, and the type of sprinkler heads used. Understanding system demand is essential for the proper sizing of the water supply and the layout of the piping system, which ultimately impacts the effectiveness of fire protection measures in place.

This concept is central to fire protection design, as it directly relates to ensuring that adequate resources are available under emergency conditions, while the other choices do not encapsulate the specific requirements outlined in NFPA 13 in relation to flow and pressure needs during a fire event.