Water Mist System (Hi-Fog)
A water mist system protects an engine room or similar space by discharging fine, high-pressure water droplets that cool the fire and displace oxygen at the seat of the flame, using a fraction of the water volume a conventional sprinkler or deluge system needs for the same space.
What to check on a Water Mist System (Hi-Fog).
21 models from Tyco / Johnson Controls in Water Mist System (Hi-Fog). Below: the full model list.
What makes this type distinct
A water mist system fights fire with very fine, high-pressure water droplets rather than the coarse spray of a sprinkler or deluge system. The small droplet size gives a large surface area for the water volume discharged, so the mist absorbs heat fast, partially vaporises into steam that displaces oxygen locally, and cools the surrounding gases enough to slow re-ignition - all with a fraction of the water a conventional system needs for the same enclosure. That matters on a ship, where flooding an engine room with deluge quantities of water raises stability concerns and can damage machinery that a fire itself might have spared. Hi-Fog is the best-known proprietary system in this category, but several manufacturers build comparable high-pressure mist installations.
Legend
- detection & control panel
- mist nozzles
- accumulator
- fine water mist
- high-pressure pump unit
- section valve
- engine room (protected space)
Main components
Pump unit
High-pressure pump set, often driven by an electric motor with a diesel-driven standby pump, building working pressures far above a conventional sprinkler system.
Nozzles
Precision nozzles that atomise water into fine droplets at the design pressure; nozzle spacing and orientation are engineered per protected space, not spread on a generic grid.
Read the full guide
Section valves and piping
Stainless steel piping able to hold the working pressure, with section valves that isolate and release water only to the zone where fire is detected, limiting water damage to spaces not on fire.
Detection and release panel
Fire detectors linked to a release panel that opens the correct section valve automatically or on manual release, with local and bridge alarms and a means to record activation.
Water supply and tank
Dedicated fresh or treated water tank sized for the discharge duration required by the protected space, kept isolated from other domestic water systems.
Selection and sizing
System design is driven by the protected space's volume, ventilation arrangement, and fire risk category - a machinery space with open engines is treated differently from an enclosed cargo pump room. Discharge duration and water demand come from the approved system design for that space type, tested and certified rather than calculated from first principles by the installer. Pump capacity and tank volume must cover the largest single protected zone likely to discharge at once, plus the standby pump's ability to take over without interrupting protection.
- Protected space volume, layout, and ventilation openings
- Required discharge duration for the space's fire risk category
- Pump redundancy - electric plus diesel-driven standby is standard on larger installations
- Zone isolation, so a discharge in one space does not empty the system for another
- Compatibility of piping material with the water supply, avoiding scale or corrosion blocking nozzles
Regulations and class
Fixed water-based fire suppression for machinery spaces falls under SOLAS Ch. II-2, and equivalent water mist systems must be tested and approved against the IMO's guidelines for equivalent fixed fire-fighting systems in machinery spaces, since water mist is accepted as an alternative to CO2 or foam flooding only where it has passed the relevant full-scale fire tests for that space type. Class societies survey the system at defined intervals - pump performance test, valve operation, and a check of nozzle condition - and any modification to the protected space's layout requires the system's approval to be reviewed.
Typical faults
| Fault | Consequence |
|---|---|
| Nozzles partially blocked by scale or debris | Reduced or uneven discharge pattern, weak spots in fire coverage |
| Section valve stuck or wrongly labelled | Water discharges to the wrong zone or not at all on activation |
| Standby diesel pump not exercised | Fails to start when the electric pump is unavailable during a real fire |
| Water tank level low or contaminated | Insufficient discharge duration, or nozzle fouling from sediment |
| Detection panel not linked to the correct zone | Alarm and release triggered in the wrong section |
What to look for in a supplier
- Full-scale fire test approval covering the specific protected space types on the vessel
- Documented zone and nozzle layout matched to the actual machinery arrangement, not a template
- Access to spare nozzles and valves without long lead times, since a blocked nozzle should not wait months
- Commissioning test records including pump pressure and flow at the design point
- Service technicians trained on the specific proprietary system installed, Hi-Fog or otherwise
Log every partial or test discharge and check nozzles in the affected zone afterwards - a nozzle that mists cleanly on commissioning can silt up over years of standing water in the pipework and nobody notices until the one time it has to work.
Models in this type.
The best-documented model of each manufacturer first, then the next — 21 of 21 models in Water Mist System (Hi-Fog). Every row links to full specifications, documents and service notes.
Manufacturers.
All 21 manufacturers with models of Water Mist System (Hi-Fog). Names with a manufacturer page open it; the others open a search across the full library.
All manufacturers in the libraryAlso in Fixed Fire Suppression.
The other equipment types in this category.
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Questions that come up with this equipment.
Is Water Mist System (Hi-Fog) data free?
Yes. Every model page, every guide and every datasheet for this type is readable without an account. An account adds saved searches and requests, nothing is taken away.
My model is missing — what now?
Send us the nameplate. We identify it by hand, add it to the library, and if you need a part or a service, the request is already on our desk.
Can you source a Water Mist System (Hi-Fog) part?
Yes. Tell us the manufacturer, the model and what you need — a person reads every request and replies by e-mail.