What is NFPA 750?
NFPA 750 is the Standard on Water Mist Fire Protection Systems, published by the National Fire Protection Association. It establishes minimum requirements for the design, installation, maintenance and testing of water mist systems based on engineering principles, fire test data and field experience. Where NFPA 13D prescribes specific design rules for residential sprinklers, NFPA 750 takes a performance-based approach: it sets the framework, but reliance is placed on listed equipment that has demonstrated performance through fire testing, installed in accordance with the manufacturer’s instructions.
How does NFPA 750 define a water mist system?
NFPA 750 covers all water mist systems, classified by operating pressure into low-pressure, intermediate (or medium) pressure, and high-pressure systems. The standard defines water mist as a spray composed of fine droplets that suppress fire through three mechanisms working in combination, cooling the flame and surrounding air, displacing oxygen as the droplets vaporise, and attenuating radiant heat, rather than through the bulk wetting action of a conventional sprinkler.
The 2023 edition introduced a new subcategory recognising electronically actuated nozzles:
3.3.25.2 Electronically-Operated Automatic Water Mist Nozzle. Nozzles that are normally closed and operated by electrical energy that is initiated and supplied by fire detection and control equipment.
This is the category Automist falls into: a water mist system in which the nozzles are held closed in standby and opened by an electrical signal from an integrated detector, rather than by the thermal element used in a traditional fusible-link sprinkler.
Where does Automist sit within NFPA 750?
Automist is a Listed targeted water mist system intended for one- and two-family dwellings. It is tested and certified under UL 2167A, the Outline of Investigation for Targeting Water Mist System Units for One- and Two-Family Dwellings for Fire Protection Service, which itself references NFPA 750 as the applicable installation standard. Automist falls within the electronically-operated automatic water mist nozzle category recognised by the 2023 edition.
In US code adoption, NFPA 750 connects to the building and fire codes through International Fire Code (IFC) and California Fire Code (CFC) Section 904.11, which permits Listed water mist systems to be installed in occupancies where they have been Listed for use, including as an alternative to NFPA 13D sprinklers in dwellings — provided the system is Listed for the purpose and installed in accordance with that Listing and the manufacturer’s instructions.
Where can I read NFPA 750
NFPA provides free read-only access to the current edition through the NFPA website. The current edition is the 2023 edition; users should check the NFPA website for any Tentative Interim Amendments (TIAs) or Errata in effect, as these can amend the standard between revision cycles.
Disclaimer: This information is not intended to be a comprehensive guide to all of the aspects of the building/fire code but rather a useful source of background information. Whilst every care has been taken to ensure that the contents of this post are correct at the time of publication, it should never be used as any form of substitution for the full NFPA® codes, standards, recommended practices, and guides. It should be noted that there may be specific additional requirements dependent upon the Authority Having Jurisidiction (AHJ).
UL 2167A is the UL standard certifying Automist, created for electronically controlled, targeted watermist systems in a residential settings. It requires systems to demonstrate they can “control, extinguish, or suppress fire” through rigorous testing in realistic scenarios, while also verifying spray performance and reliability under real-world conditions. Applicable to wall-mounted systems in one- and two-family dwellings and installed in accordance with NFPA 750, it provides AHJs and insurers with an independent, recognised basis that the system can reduce fire risk and protect life.
Learn moreYes — Automist can be used as an alternative to an NFPA 13D fire sprinkler system in domestic occupancies, where permitted by the local Authority Having Jurisdiction (AHJ). Automist is not an extinguishing system; it is a fire suppression system that is specifically designed and Listed for domestic use, meeting the intent of NFPA 13D sprinkler protection.
Learn moreAutomist is UL-listed under UL 2167A, certifying it as a residential water mist fire suppression system in line with NFPA 750, with proven performance, safety, and reliability through rigorous independent testing. This certification is widely recognized by regulators and insurers, and can be verified under File Number EX29276 on the UL Product iQ database.
Learn moreWatermist is a water spray for which the cumulative volumetric distribution of water droplets is less than 1000 μm (1mm) within the nozzle operating pressure range. The use of watermist technology to safeguard building inhabitants and assets has gained popularity over the last 30 years. Watermist does this by maximising the efficiency and effectiveness of droplet deployment. The methodology varies depending on both the manufacturer and the application, from the nozzle design, appearance, spacing, activation method, location to orientation.
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