NFPA 13: Sprinkler System Design & Installation Fundamentals

By Andrew Erickson

May 21, 2023

Fire safety is integral to every building, whether residential, commercial, or industrial. The risk of fire cannot be completely eliminated, but it can be significantly mitigated with the right measures in place.

Sprinkler systems, a vital part of any fire safety strategy, are guided by precise standards to ensure their effectiveness. I've previously listed the best manufacturers of fire alarm sprinkers for you. We're now going to review an absolutely critical standard: NFPA 13, the Standard for the Installation of Sprinkler Systems.

NFPA 13, developed by the National Fire Protection Association, provides comprehensive guidelines for the design and installation of automatic sprinkler systems. By adhering to NFPA 13, you can maximize the effectiveness of your sprinkler systems. This saves property and, more importantly, lives.

Design and Installation Requirements

NFPA 13 provides detailed specifications for the design and installation of sprinkler systems. These specifications include:

  1. System Type: The standard covers several types of sprinkler systems, including wet, dry, pre-action, and deluge systems. It specifies the appropriate system type based on various factors like building use, contents, and environment.
  2. Sprinkler Positioning: NFPA 13 provides guidelines on how to position sprinklers to cover the maximum area effectively. It includes specifics on the spacing between sprinklers, distance from walls, and the area each sprinkler should cover.
  3. Water Supply: Adequate water supply is crucial for the sprinkler system to function effectively. NFPA 13 defines requirements for the water supply duration and pressure, ensuring that the system can function effectively in the event of a fire.
  4. Pipe Sizing and Material: The standard outlines specifications for the pipes used in the sprinkler system, including their size, material, and the pressure they must withstand.
  5. Installation Practices: NFPA 13 provides guidelines on how to install the system, including how to hang and brace sprinkler pipes, and install sprinklers and valves.

5 Different Sprinkler System Types

  1. Wet Pipe Systems: This is the most common type of sprinkler system and the simplest in terms of its configuration. As the name suggests, the pipes in a wet pipe system are filled with water at all times. When a fire causes a sprinkler to activate, water is immediately discharged onto the fire. Wet pipe systems are reliable and low-maintenance. Unfortunately, they're not suitable for environments where the water in the pipes could freeze.
  2. Dry Pipe Systems: In dry pipe systems, the pipes are filled with pressurized air or nitrogen, rather than water. When a sprinkler activates, the air pressure is released, allowing water to flow through the pipes and onto the fire. These systems are designed for environments where the ambient temperature may be low enough to freeze water in the pipes. That makes them useful in install scenarios such as unheated buildings or outdoor areas.
  3. Pre-action Systems: Pre-action systems are a bit more complex and operate similarly to dry pipe systems in that the pipes are filled with pressurized air. However, pre-action systems require a separate triggering event to activate the water flow, usually a signal from a heat or smoke detector. This two-step activation process reduces the risk of accidental discharge, making pre-action systems ideal for environments where water damage from a false alarm would be particularly harmful, such as data centers or libraries.
  4. Deluge Systems: Deluge systems are similar to wet pipe systems in that they deliver a large quantity of water upon activation. However, unlike other systems, all the sprinkler heads in a deluge system are open, and they all discharge simultaneously when the system is triggered. These systems are used in high-hazard areas where rapid fire spread is a concern, such as aircraft hangars or chemical storage facilities. Oddly enough, this is one place where the movie cliche of all fire sprinklers activating simultaneously is actually true!
  5. Residential Sprinkler Systems: These systems are designed specifically for residential dwellings. They focus on rapid response to control a fire quickly, protecting lives and property. They also feature aesthetic considerations as they are designed to blend with the home decor. Homes in California now have this type of sprinkler system mandated by the AHJ.

Each system has its own unique features and applications, and the choice of system will depend on a variety of factors, including the building’s structure, its use, the local climate, and the potential fire hazards present.

Remember, it's critical to adhere to NFPA 13 standards when installing any of these systems to ensure they function effectively in the event of a fire.

Maintenance and Testing Requirements

Just installing a sprinkler system isn't enough. Regular maintenance and testing are also necessary to ensure it functions as intended. NFPA 13 provides a comprehensive list of maintenance checks and testing procedures to ensure system reliability and performance.

These include:

  • Physical inspections of the system components.
  • Pressure tests to ensure that the pressure in the pipes is sufficient for water discharge.
  • Flow and alarm tests to check whether the system can identify a fire and react appropriately.
  • Cleaning of sprinkler heads and other parts to prevent blockages or corrosion.
  • Updating of records to keep track of any changes, repairs, or upgrades made to the system.

How Do NFPA-13-Compliant Sprinklers Integrate with Fire Alarm Systems

A crucial aspect of a holistic fire safety strategy is the integration of sprinkler systems with fire alarm systems. NFPA 13 and NFPA 72 (the National Fire Alarm and Signaling Code) work in concert to ensure this integration. For instance, when a sprinkler activates, it should trigger the building’s fire alarm system. This integrated response ensures prompt notification to occupants and emergency responders.

Water flow switches and valve supervisory switches are examples of devices that monitor the status of sprinkler systems and relay that information to fire alarm control panels. Understanding and properly installing these devices in accordance with NFPA 13 and 72 is key to ensuring effective fire protection.

How Can Digitize Help You with Your Project?

Applying the intricacies of NFPA 13 to real-world projects can be a challenge. With 46+ years of experience in fire alarm monitoring, Digitize can help you.

We can provide guidance based on our experience on how to integrate your sprinkler system with your fire alarm monitoring system effectively. Although NFPA 13 and NFPA 72 are your ultimate reference documents and we are not sprinkler installers, and we can offer practical advice to help you navigate these standards in your projects. Our network of distributors and installers can also assist you with your physical installation.

Whether you're designing a new system or updating an existing one, we're here to help you deliver a reliable, code-compliant solution. Don't hesitate to give us a call at 1-800-523-7232 or email for professional guidance on your fire safety project.

Andrew Erickson

Andrew Erickson

Andrew Erickson is an Application Engineer at DPS Telecom, a manufacturer of semi-custom remote alarm monitoring systems based in Fresno, California. Andrew brings more than 17 years of experience building site monitoring solutions, developing intuitive user interfaces and documentation, and...Read More