Server rooms hold some of the most valuable and sensitive equipment on any site. They’re packed with highly sensitive, expensive electrical equipment, running continuously in small spaces with limited airflow. Flames, heat and smoke can quickly cause irreparable damage to servers, while traditional sprinkler systems can compound fire damage with water damage.
Traditional sprinklers are designed around volume and speed, with many standard systems releasing between 30–60 litres of water per minute, which can present a significant risk around sensitive electronic equipment. Sprinkler discharge can short-circuit and permanently damage servers, destroying valuable data and limiting business operations. It can also cause problems beyond the servers, soaking cabling and other equipment not even touched by the fire.
In server rooms, traditional sprinklers may present an additional water-damage risk that needs to be considered alongside their effectiveness in controlling fire.
Alternatives to traditional sprinklers
Sprinklers aren’t a bad fire suppression system; they’re cost-effective, reliable, massively popular worldwide, and for many commercial and industrial spaces, the right choice. However, there are areas, such as server rooms, where the potential for water damage requires additional consideration.
Where reducing water discharge is an important consideration, water mist systems can provide an alternative approach to fire suppression. Instead of large water droplets, water mist systems release water at high pressure through specialised nozzles, atomising it into microscopic droplets. The result is a system that uses a fraction of the water volume of a traditional sprinkler, while still suppressing fire effectively.
How do water mist systems work?
Water mist systems suppress fire through three combined mechanisms:
Cooling – Because the droplets are so fine, they have a much larger surface area relative to their volume than a standard sprinkler jet, allowing them to absorb heat faster and cool flames more efficiently.
Local oxygen displacement – As fine droplets evaporate near the fire, the resulting water vapour can contribute to reducing the concentration of oxygen available around the flame.
Radiant heat blocking – The mist forms a dense barrier between the fire and its surroundings, absorbing and scattering radiant heat, which slows the spread of fire and protects nearby people and equipment.
For server rooms specifically, water mist can provide effective fire control while reducing the potential for water damage to servers and other sensitive equipment. This, in turn, means less downtime for your business and a faster return to normal operations.
But if water mist systems can provide effective fire suppression while using less water, why aren’t they more widely used? Unsurprisingly, cost plays a part here.
Water mist systems are typically more expensive to install than traditional sprinklers, owing to their specialised, high-pressure equipment and more complex design. However, if a fire does break out in a server room, upfront cost can be offset by reduced water damage to expensive systems and the loss of valuable data.
Water mist vs traditional sprinklers
How do water mist systems and traditional sprinklers compare across things like water consumption and operational complexity?
- Water consumption – water mist systems typically use considerably less water than traditional sprinklers. This is another thing to consider when weighing up the upfront costs of the two systems
- Droplet size – water mist systems produce much finer droplets than conventional sprinkler systems, increasing the surface area available for heat absorption and evaporation.
- Complexity – water mist systems have higher operating pressures, specialised components, and more complex design, maintenance, and installation requirements.
- Potential cost – water mist systems are generally more expensive than traditional sprinklers. However, the lower water discharge associated with water mist can help reduce the potential for water damage to expensive equipment if the system activates.
- Downtime – water damage from traditional sprinklers often means longer downtime, while damaged servers are repaired or replaced.
- Relevant standards – water mist systems may be designed in accordance with the applicable parts of BS 8489, while automatic sprinkler systems are covered by BS EN 12845.
Choosing the right system for your site
It’s not always the case that one system is better than another. Many sites use traditional sprinklers in areas where they’re less likely to cause water damage, and reserve water mist systems for more sensitive areas, such as server rooms. Beyond these two options, other fire suppression methods, such as gaseous suppression and compressed air foam systems (CAFS), may also have a role to play depending on the specific hazards and layout of your site.
