Grade Plane is defined as?

Grade Plane is defined as?

• A. Design Discharge
• B. Grade Plane
• C. Combustibles
• D. Occupancy Classification

Answer: (B)

Grade plane is the reference plane that corresponds to the finished grade around the building. It sets the baseline elevation used to locate sprinklers relative to ground level and to determine whether a head is above or below grade, which affects how hydraulic calculations and water supply requirements are applied. In NFPA 13R design for low-rise residences, using this plane ensures elevations are assessed consistently, especially for sprinklers near or below ground level. Other terms refer to different concepts: design discharge is the targeted flow rate used in designing the system, combustibles describe the fuel materials involved, and occupancy classification identifies the hazard category of a space. None of these define the elevation reference used in hydraulic design.

Grade plane is the reference plane that corresponds to the finished grade around the building. It sets the baseline elevation used to locate sprinklers relative to ground level and to determine whether a head is above or below grade, which affects how hydraulic calculations and water supply requirements are applied. In NFPA 13R design for low-rise residences, using this plane ensures elevations are assessed consistently, especially for sprinklers near or below ground level.

Other terms refer to different concepts: design discharge is the targeted flow rate used in designing the system, combustibles describe the fuel materials involved, and occupancy classification identifies the hazard category of a space. None of these define the elevation reference used in hydraulic design.