Adapting to high-risk environments: FM’s approach to lithium-ion risk in mission-critical sites
Iain Hoey
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Adrian Oxley, Principal Engineer for Semiconductor/ Digital at FM discusses managing risks across unique environments and how to overcome challenges
To begin with, could you introduce yourself, your role and how your work relates to lithium-ion battery risk in mission-critical environments?
My name is Adrian Oxley and I am the Principal Engineer for Semiconductor/ Digital at FM.
I oversee the technical side of our book around data centres.
I am responsible for making sure that our resources, operating standards and the 2,213 field engineers that work throughout the globe have a strong understanding of the data centre industry.
I also have a link between our clients, the Chief Engineers group that I work in and our research department.
When our clients have technically challenges, we help to focus our research on the issue in order to offer mitigation strategies.
Additionally, I work in close collaboration with our underwriting side of the business to make sure that the engineers are providing relevant information.
What are the main causes of battery failure in data centres and telecom infrastructure, and how do these differ from risks seen in other sectors?
It doesn’t matter what industry you are focused on, whether that be data centres or the automotive industry, you need to be aware of the failures associated with lithium-ion batteries and how they can be categorised.
These categories range from manufacturing faults, mechanical damage and electrical abuse.
There are also typical external type events like electrical failures for short circuits and grounds etc.
They can all cause damage to the batteries and therefore risk putting them into thermal runaway.
How does early off-gas detection work in practice and what kind of indicators or thresholds are most relevant for operators to understand?
Off gas detection works when a lithium-ion cell starts to fail and goes into thermal runaway.
The cells begin to off-gas and the off-gas is the product of a chemical reaction that happens within the cell.
Having the ability to detect something going very wrong early on within that cycle is a positive advantage because it allows you to react proactively once you realise the issue is there.
Off-gas detection is focused on very, very small quantities due to the off-gases being around 10 parts per million.
Where does water mist suppression fit into a layered response, and what features make it suited to technical environments with sensitive equipment?
Water mist is one of the tools in our toolbox.
There are both advantages and disadvantages to these systems but overall, water mist allows us to provide effective fire protection.
I think the key thing to get across is that a water mist system must be specified based on how it’s been tested and what it has been approved for.
If you put a water mist system into an environment that it has not been tested or designed for then it’s not going to do what it’s supposed to do.
This means that you have got to be very careful with water mist systems when it comes to the protection of lithium-ion batteries- certainly within a data centre environment, making it sure it has been approved for the application.
Can you explain how detection and suppression can support each other when integrated as a single mitigation strategy?
The detection system must be a part of an overall mitigation strategy because the system on its own is not really going to do anything for us- it won’t put the fire out; it is only able to tell us that there is a problem.
Ultimately, it is from using the signal from that detection system that we can react hopefully before a fire starts.
With off-gas detection for instance, using that signal to cut the power to the chargers for the battery or cut an electrical breaker to stop the power associated with those batteries is going to give us some benefit.
Effectively, we can use the signal from the detection system, whether that be off-gas or smoke detection, to trigger the water system into action.
Water will be released and the system will use the heat of the fire to let water out of the pipework in a pre-action system.
Are there challenges in retrofitting these systems into existing facilities or when aligning them with other safety controls?
The challenge of a data centre environment is that once the environment is operational, the opportunity to go in there and start fitting fire protection systems is very remote.
An operator would typically not want to do this retrofit.
This is why it is really important to consider the fire protection strategy at the very early concept of a building.
At that point in time, we can design the system properly and take all the building parameters into consideration during the design.
Certainly, when we are looking at data centres we need to be considering things like high velocities of airflow as this can have a significant impact on the detection system.
If there is a high volume of air flowing through the hot or cold containment this can impact the system operation.
You need to consider if it is feasible to fit a water-based system, such as a sprinkler system, into an existing system.
Yes, it is feasible, but it is also very expensive and challenge.
All of these factors need to be taken in consideration.
Operators are far better off incorporating detection systems into the overall design from a very early stage.
It is very difficult to link existing detection systems because they are designed to be holistic.
Are there any common misunderstandings about lithium-ion risk management in mission-critical sites that you think need clarification?
A lot of the time, people talk about the fire hazard associated with lithium-ion- which is a well-known phenomenon.
The data centre industry especially has seen several recent incidents.
In Korea, there was a government wide shut down for a number of days after a lithium-ion battery system was removed from a data system.
There was also a significant incident Singapore which involved an explosion that caused a substantial amount of damage.
I think this is a factor that is underestimated within the industry because many people do not realise that we’re not dealing with a fire hazard- but an explosion hazard, too.
Therefore, I believe that as part and parcel of the strategy of introducing lithium-ion batteries into data centres, additional factors need to be taken into consideration, such as the location of the batteries, the size of the room associated with it and how the room might react to an explosion.
These are all important things that we look at as FM when evaluating a battery system.
How do you see battery technology, regulatory expectations or infrastructure design influencing this topic over the next few years?
I think the industry is really at a crossroads now.
Previously, everyone worked to the UL Standards when it came to getting batteries certified, but we are now seeing the authorities having more influence.
This means that the people who give the occupation certificates to data centres are turning around and saying the tests they have previously done are not sufficient anymore in proving that the system is not going to cause a significant fire or even an explosion.
Really, the way they are coming as it is because firefighters are going into buildings and facing potential injury because of the high-risk environment[AO1.1], potentially caused by the fire and explosion risk present.
A lot of the authorities having jurisdiction now are asking for large scale fire tests to actually prove the performance of the batteries in a real-life scenario.
This uptake in desire for large scale fire testing is changing the regulatory landscape indefinitely.
Battery technology is changing simultaneously; we are seeing different technologies emerging within the industry and it is important to recognise that we cannot rule out that something worse than lithium-ion might be coming along.
Batteries are an important part of data centres, they’re not going to go away, but the application of them must be taken into consideration moving forward.
At FM, our responsibility is to help the industry navigate this moving forward.