Why the prolonged firefighting at Digital Realty's data centre?
Why fire trucks are still there 24 hours after a fire broke out.
It's over 24 hrs since a fire broke out at Digital Realty's data centre, and fire trucks are still there. Here's why.
Yesterday, I wrote about a fire at the SIN11 data centre that impacted Alibaba Cloud's Availability Zone C.
There's been further developments.
Lithium-ion batteries on fire
Digital Realty has since issued a statement. In a nutshell:
- The fire that started at 7.45am on Tue morning.
- 20 individuals evacuated from building.
- No injuries reported.
The SCDF responded to the fire at the SIN11 data centre and has worked to "secure the premise" and "stabilise the situation" since.
According to a SCDF spokesperson to CNA last night:
- The fire involved lithium-ion batteries.
- In the third-level battery room of building.
- A "prolonged operation" was expected.
A prolonged operation
Why a prolonged operation for a simple fire? According to eyewitness, fire trucks were still present at SIN11 data centre as of noon today.
The reason:
- Lithium-ion battery fires are prone to reigniting.
- Non-trivial risk of explosion.
- Toxic fumes is released.
The ability of lithium-ion battery fires to reignite is due to the fact that lithium salts are self-oxidising, so can't be starved out like a traditional fire.
The only option? Cool everything to a sub-igniting temperature (< 500°C). This entails using lots and lots of water while monitoring for flareups - which can still happen.
Problems of ponding
The above explains why the SCDF deployed an unmanned firefighting robot to cool the batteries, why fire sprinklers in the battery room were not deactivated, and why the procedure called for employees to evacuate.
Of course, dumping tens of thousands of litres of water into a room is a receipe for flooding. Which isn't conducive to servers and can lead to electrocution.
Responding to a query by The Register at 1:45am this morning, Digital Realty confirmed that it had powered down some electrical systems in SIN11.
Why use lithium-ion batteries
On the whole, the data centre industry has been moving from traditional lead acid batteries towards lithium-ion ones for UPS.
It does offer quite a few advantages:
- High-power density (Less space).
- 10-year lifespan for low TCO.
- Almost zero maintenance.
- Faster charging.
On the other hand, some argue that the industry as a whole has not done enough work on evaluating its safety for widespread data centre deployments.
What do you think?
[6:00pm, 12 Sep] Digital Realty has released a new press statement an hour ago.
Key points:
BCA has conducted a preliminary assessment and identified minor structural damage. Building's structural integrity not affected.
[As precaution], BCA issued a Dangerous Building Order (DBO) and a Closure Order (CO) for specific areas of the facility. A Professional Engineer has been commissioned to conduct a full assessment of the building’s structure.
