Les Bell
Blog entry by Les Bell
Welcome to today's daily briefing on security news relevant to our CISSP (and other) courses. Links within stories may lead to further details in the course notes of some of our courses, and will only be accessible if you are enrolled in the corresponding course - this is a shallow ploy to encourage ongoing study. However, each item ends with a link to the original source.
News Stories
Lithium-Ion Battery Fires Increasingly Common
A CBS News report points to the rising incidence of fires caused by lithium-ion batteries, particularly in dangerous environments such as on board passenger aircraft. According to the CBS News investigation, the FAA verifies that the number of lithium-ion battery fires has jumped by over 42% in the last five years, and since 2021 there has been at least one such incident on a passenger plane somewhere in the US, on average, every week.
However, the article points to a common source of confusion - it is lax in making the important distinction between lithium batteries and lithium-ion batteries - the two terms are used apparently interchangeably in the article. The CISSP examination tests the candidate on physical and environmental security, including fire detection and suppression, and while I cannot say whether the exam question bank has any questions on this particular topic, the increasing prevalence of mobile devices which contain these batteries surely mean that it can only be a matter of time. So here's some key information from the Fire Detection and Suppression page of our CISSP Fast Track Review course wiki.
The first key point is to distinguish between the two types of battery:
- Lithium batteries are long-life, non-rechargeable batteries commonly used in wireless burglar alarm sensors, smoke detectors (usually in AA and AAA cell sizes), and in cameras, some remote controls and key fobs (usually in button-cell sizes such as CR-2032).
- Lithium-ion batteries are rechargeable batteries, commonly used in a variety of sizes and form factors, in mobile phones, tablets, laptops, Bluetooth earbuds and headphones, vapes and many other devices.
Let's dispose of (if you'll pardon the expression) the lithium batteries first. The first, and key, point is that lithium batteries are not rechargable and any attempt to recharge them may well start a fire. They will also overheat and may catch fire if short-circuited, or if exposed to water. In fact, lithium (like potassium) is a combustible metal that burns when exposed to air or even water - readers may remember high-school chemistry demonstrations in which a small pellet of potassium fizzes and burns when dropped into water - it is commonly stored in a jar of mineral oil as a safeguard, as is refined lithium metal.
Obviously, water therefore cannot be used as a suppressant for a lithium battery fire - in fact, adding water will result in a bigger fire - and so a large lithium battery fire should be tackled with a Type D (combustible metals) extinguisher. Unfortunately, these are not commonly found in office environments (yet?).
By contrast, a lithium-ion battery fire should be suppressed using a conventional ABC dry-powder extinguisher, although it may not be fully extinguished if thermal runaway continues. If one is available, a fire containment bag can also be used. Immersion in water may also be used - the battery may continue to burn, but the heat will be conducted away and the fire contained. In fact, it is not lithium that is the problem - it is the flammable electrolyte solution in the battery. Where the volume of Li-Ion batteries justify it - e.g. large quantities of Li-Ion batteries are stored in a warehouse - then a specialized F-500 Li-Ion Fire Extinguisher may be installed.
There are several causes of Li-Ion batteries fires. The first is mechanical damage to the battery - i.e. it is bent and broken, for example by being caught in the electrically-driven adjustment mechanisms of an aircraft seat. This is why airline staff warn passengers to ask for help in retrieving phones which have been lost in aircraft seats.
The second cause is a short-circuit, possibly caused by equipment failure, and the fix is to remove the battery from the device before thermal runaway starts. The third cause is overheating - this can be caused by laptop fan failure, an internal dust buildup or operating a laptop on a surface which blocks airflow. For phones, it can be as simple as using navigation functions, which continuously illuminate the screen, while the phone is in direct sunlight on top of a car dashboard.
The final cause is overcharging. Unlike the earlier nickel-cadmium (Ni-Cd) batteries, Li-Ion batteries are very sensitive to overcharging and require the correct charging circuit, which must provide overcharge protection. In general, laptop and cellphone or tablet batteries always contain a charging control circuit which deals with this, but small AA-size Li-Ion cells do not, and nor do some low-cost consumer devices and toys. These, in particular, should never be left to charge unattended, nor in a place where fire could rapidly take hold and spread, e.g. on top of soft furnishings or beneath fabric curtains.
Chase, The Best Fire Extinguisher for Lithium-Ion Batteries - 2022, Firefighter Inside, 2022. Available online at https://firefighterinsider.com/the-best-fire-extinguisher-for-lithium-ion-batteries/.
Martin, Neil, Seven things you need to know about lithium-ion battery safety, UNSW news release, 20 March 2023. Available online at https://newsroom.unsw.edu.au/news/science-tech/seven-things-you-need-know-about-lithium-ion-battery-safety.
Stock, Stephen, Amy Corral, Jose Sanchez and Dilcia Mercedes, Rising number of lithium battery incidents on airplanes worry pilots, flight attendants, CBS News, 8 May 2023. Available online at https://www.cbsnews.com/news/hazardous-materials-airplanes/.These news brief blog articles are collected at https://www.lesbell.com.au/blog/index.php?courseid=1. If you would prefer an RSS feed for your reader, the feed can be found at https://www.lesbell.com.au/rss/file.php/1/dd977d83ae51998b0b79799c822ac0a1/blog/user/3/rss.xml.
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