A large open room with hundreds of Kilowatts or even Megawatts of electrical energy being consumed and a set of powerful fans blowing air in sounds like an ideal place to make a great fire! Detecting fire quickly and extinguishing it before it takes hold is a critically important feature of all data centers.
Early smoke detection is performed by VESDA which works by sucking air into a mesh of pipes connected into a highly sensitive smoke detector. The detector shines a laser light through the collected air and checks for smoke in the airflow by detecting the light scatter that this causes to the laser beam. The detector sends a signal off to a control system that typically sets off an audible alarm and sends an alert to a Building Management System for manual investigation.
Typically data centers have a secondary system that takes more extreme action which may include:
- Setting off an audible fire alarm
- Shutting down equipment in the room
- Triggering the release of fire suppressant
The options for fire suppressant are varied and include:
- Water sprinklers
- Fine Water Mist
- Halon Gas (now banned)
Water sprinklers cause damage to expensive computer equipment when discharged but are safe for humans and cheap to install and maintain.
Fine water mist uses the same principle as outside air conditioning, by dropping the temperature at the area of discharge to extinguish fire. By using ultra pure water, damage can be minimized.
Argonite is a very popular 50/50 mix of Nitrogen and Argon, two inert gasses that do not support combustion.
Innergen is also popular and similar to Argonite with the addition of Carbon Dioxide.
Halon is banned in most developed countries because it is a greenhouse gas and damages the ozone layer.