Data Center Dynamics reported last week, Aruba, Italy’s largest web hosting data center, went down due to a fire in the UPS room involving the batteries. 
“Battery fires happen,” said Uptime Institute Professional Services Consultant, Chris Brown. “Once the fire starts the battery can feed the fire until it exhausts its energy. More information on this particular incident would be needed to know if this was or was not an avoidable situation (i.e. if it was the result of a thermal runaway or some other issue). But thermal runaway would be the biggest concern I would have for a cause of a battery fire.”
There are ways to help avoid thermal runaway, according to Brown. Those would include but not be limited to keeping the batteries and charging means (UPS) in good condition and repaired, a battery monitoring system that monitors the cell temperature of each battery, and temperature compensated charging.
“Basically the best way to avoid battery issues is to stay on top of the preventative maintenance of the batteries and charging means. Regular preventative maintenance can spot problematic batteries or cells before they fail internally that can lead to a thermal runaway as well as allow technicians to adjust charging voltage and current to ensure the batteries are not overcharged,” Brown said. “Batteries are combustible there is always a risk of fire from batteries. And that risk should drive where batteries are placed and the type of fire extinguishing means used for the room.”
Terral Altom, Uptime Institute Professional Services consultant said batteries can and often do build up heat and hydrogen, and under the right circumstances, a fire can erupt. “The trouble with wet cell batteries is that they have plastic jars, and these jars are highly combustible.”
Some insurance underwriters require a sprinkler system in battery rooms. In an anecdotal account told to Altom, a flooded cell battery room caught fire, and the gaseous suppression system discharged. The smoldering battery jars reignited after the suppressant gas dissipated. The data center team then had to call the fire department, and by the time they got there, it took 45 minutes to extinguish the fire. Due to smoke and water damage, much more than the battery rooms were damaged.