FM Approved high-pressure water mist system expands certified protection options for HC-2 and HC-3 occupancies

Marioff’s HI-FOG ® high-pressure water mist system, designed for the protection of Hazard Category 2 (HC-2) and Hazard Category 3 (HC-3), has been tested and certified to the requirements of FM Approvals Examination Standard 5560 for Water Mist Systems.

HC-2 occupancies are predominately defined as areas with moderate continuous combustible loading with combustibles in processes or operations of moderate hazard due to limited quantities of plastics or ignitable liquids. Examples include manufacturing (machine shops, woodworking, electronics assembly, etc.) as well as retail, theaters, and food production.

HC-3 occupancies represent a higher fire risk compared to HC-2 and are predominately defined as areas with generally continuous higher combustible loading with limited quantities of ignitable liquids and heavier amounts of plastics. Higher ceiling heights and other factors that could increase fire spread often factor into an occupancy’s classification as HC-3. Water-based fire protection of HC-3 occupancies generally require more discharge thanHC-2 occupancies.

Water mist fire suppression can be implemented in various occupancies including automotive production facilities, data centers, food processing plants, healthcare facilities, and more.

In June 2025, FM Approvals certified VID FIREKILL’s low pressure water mist system to the requirements of FM Approvals Examination Standard 5560. With the addition of Marioff’s HI-FOG® high-pressure water mist system, there are now multiple FM Approved water mist solutions available to mitigate and stop fire spread in HC-2 and HC-3 occupancies. Stakeholders can access the Approval Guide to learn more about the applicability of these and other FM Approved fire protection products. Contact your local FM Approvals office for additional guidance.

FM Approvals has been evaluating loss prevention products since 1886. With 130,000+ FM Approved products, our globally recognized certification process is backed by technical integrity and confirms product performance under real-life conditions. If you manufacture loss prevention products or are in search of a solution to protect your facility from evolving risks, please reach out to us at [email protected] to learn more.