It multiplies the total surface area enormously, and evaporation happens at the surface.

A conventional sprinkler produces droplets measured in millimetres; mist produces microns.

The mist absorbs heat far more efficiently per litre of water used.

Steam produced by that evaporation displaces oxygen locally at the fire.

So a small volume of water does the work of a much larger one.

The change in behaviour is disproportionate to the change in droplet size.

Marine installations, heritage buildings, machinery spaces and local application onto specific equipment.

On ships, tank capacity is limited and weight matters directly.

In heritage buildings water damage to the fabric is as serious as fire damage.

Machinery spaces and turbine halls suit local application onto a defined hazard.

Smaller tanks and pumps also suit retrofits where plant space is limited.

For a conventional building with a good water supply, sprinklers are simpler and cheaper.

Much higher operating pressures, small nozzle orifices and generally stainless pipework.

Pumps, pipework and fittings are all rated for the higher pressure.

Small orifices make water quality a real design consideration.

Filtration is part of the system, because contaminated water blocks nozzles.

Installation requires different skills and testing from conventional sprinkler work.

Component compatibility within a listed system matters more than with sprinklers.

By full-scale fire testing for specific applications rather than by general hydraulic calculation.

That is the most important difference when specifying one.

A system approved for a machinery space is not thereby approved for a hotel corridor.

The approval names the application, and the design must fall within what was tested.

Manufacturers publish the tested applications and the parameters that apply.

Extrapolating beyond the tested scenario is not a design decision anyone can make locally.

More than for sprinklers, because part of the mechanism is local oxygen displacement.

Strong ventilation or a large opening can carry the mist away before it works.

Door and ventilation interlocks appear in many designs for that reason.

It is not the same requirement as gaseous enclosure integrity, but it is not nothing.

The tested application will state the enclosure conditions assumed.

Open or highly ventilated spaces may need a different approach entirely.

Generally yes - it is water, and the quantities are small.

Visibility is reduced during discharge, which affects escape and is part of the design.

There is no oxygen depletion hazard of the kind gaseous systems create.

Local application onto energised equipment needs the usual electrical considerations.

Steam produced at the fire is hot and is a local hazard rather than a room-wide one.

That combination is part of why it is used in accommodation and heritage settings.

Water quality management, nozzle condition, pump testing and periodic functional testing.

Filtration is checked and maintained, since nozzle blockage is the main failure mode.

Nozzles are inspected for blockage and damage.

High-pressure pumps have their own testing regime.

Water stored in tanks may need treatment to prevent biological growth.

Requirements come from the system manufacturer and the local standard together.