NFPA 13: Automatic Sprinkler Systems

NFPA 13 is the standard for the installation of sprinkler systems, providing requirements for the design and installation of automatic fire sprinkler systems. This standard is the most widely used sprinkler system installation standard in the world and is referenced by building codes throughout North America.

The 2022 edition includes updated requirements for storage applications, seismic protection, and system design approaches. NFPA 13 works in conjunction with NFPA 25 for inspection, testing, and maintenance requirements.

NFPA 13 covers four primary sprinkler system types:

• Wet Pipe Systems: Pipes continuously filled with water, most common and reliable type
• Dry Pipe Systems: Pipes filled with pressurized air or nitrogen, used where freezing is a concern
• Preaction Systems: Combination of dry pipe and deluge systems, requires dual activation
• Deluge Systems: Open sprinklers with dry piping, used for high-hazard areas
• Antifreeze Systems: Wet pipe systems with antifreeze solution for freeze protection

NFPA 13 defines occupancy hazard classifications that determine design requirements:

Key design requirements include:

• Water Supply: Adequate flow and pressure for system demand plus hose stream allowance
• Hydraulic Calculations: Required for all systems except residential and limited area systems
• Sprinkler Spacing: Maximum coverage area per sprinkler based on hazard classification
• Design Area: Most hydraulically demanding area based on occupancy and storage arrangement
• System Components: Listed components including sprinklers, piping, valves, and hangers
• Seismic Protection: Bracing requirements for areas subject to earthquakes

Critical installation specifications:

• Piping: Steel, copper, or CPVC materials meeting specific standards
• Hangers: Proper spacing and type based on pipe size and material
• Sprinkler Position: Deflector orientation and distance from ceilings/walls
• Obstructions: Rules for sprinkler placement around beams, ducts, and fixtures
• Control Valves: Listed indicating valves in accessible locations
• Alarms: Waterflow alarm devices on all sprinkler systems
• Fire Department Connection: Required for systems with standpipes

Upon completion, systems must be tested per NFPA 13 requirements:

• Hydrostatic Test: 200 psi for 2 hours or 50 psi above system pressure
• Flushing: Underground and aboveground piping before final connection
• Main Drain Test: Verify water supply adequacy
• Alarm Test: Verify waterflow alarm activation
• Documentation: As-built drawings, hydraulic calculations, and material certifications
• Ongoing Maintenance: Follow NFPA 25 for inspection, testing, and maintenance

NFPA 13 works in conjunction with NFPA 25 for inspection, testing, and maintenance. Fire alarm connections follow NFPA 72 Fire Alarm Code requirements. For portable protection, see NFPA 10 Fire Extinguisher Standards.

Learn about inspector certification requirements in our Fire Inspection & Compliance Guide.