Water mist fire protection is a relatively new form of fire suppression providing an alternative to the conventional fire sprinkler methodology. There has been and is still speculation surrounding water mist systems and how effective they really are in extinguishing fire. Water mist technology has evolved rapidly over the last 10 years, and while the technology isn’t new, it is still under the scrutiny of fire professionals with a number of technical papers and research efforts still being developed in order to fully understand water mist capabilities.
Unlike the sprinkler system, water mist systems break water into a cloud of small water droplets and increase the surface area available for absorbing heat. The technology works on the basis that the smaller water particles are, the more rapidly heat can be extracted from an environment. But this doesn’t necessarily mean that fire is put out more efficiently by water mist protection systems.
Water mist fire protection is generally used where fire sprinklers cannot meet the objective of fire protection. Perhaps where expensive electrical equipment needs protection from water damage, or in museums where artefacts must be preserved at all costs. Again, there is divided opinion within the fire protection industry as to whether water mist systems are as effective in saving specific contents of a building as manufacturers claim. For example, art galleries have become aware that oil paintings can be completely spoiled by water mist.
When considering whether to install a water mist fire protection or fire sprinkler protection, a fire engineer must consider if water mist will provide a significant engineering benefit, such as better fire control, lower water requirement or smaller pipe sizes. The benefits must justify the installation; a customised water mist system can be very expensive, and if the benefits are not significant then a fire sprinkler system will be installed.
Another important consideration is that the only way to
know if a water mist protection system will be effective
for its purpose is to carry out live fire testing
in a simulated environment. Fire sprinklers on the
other hand provide a proven blanket protection from
the outset, in that fast fire extinguishment and the
protection of occupants is guaranteed. However, although
fire sprinklers provide exceptional damage limitation
by localising a fire at the source of origin, there
is no guarantee that electrical equipment and other
valuable belongings won’t be damaged beyond
repair. That said, when it comes to fire, the most
important aspects of fire protection are saving lives
and preventing injury.