Thermarestor: A predictive solution for electrical and lithium-ion battery fires?

Electrical fires remain a prominent issue, while new threats from lithium-ion batteries are also on the rise. Though much of the mitigation solutions have understandably focused on post-ignition measures to prevent the spread of fire, Thermarestor is a device that is said to address the issue pre-ignition at source, continuously monitoring heat in electrical fixtures to provide a predictive warning. Matthew McKaig, Director of Communications at Thermarestor, explains.

Helping to tackle the problems faced

The idea of Thermarestor emerged because there was not a low cost and accessible product on the market which could alert a third party to excessive, but pre-ignition heat in electrical locations.

Anything that uses electricity as a source of supply has the potential to cause a fire. In the UK alone there are approximately 25,000 fires of an electrical origin each year – and the issue isn’t just confined to the UK.

Thermarestor is designed to prevent incidents such as this from happening via predictive maintenance and alerts

The major cause of fires involving fixed wire installations is localised resistive heating – loose, poorly made and oxidised electrical connections generates excessive heat, often confined to a relatively small area. If the heating process continues unnoticed over a period of time, Thermal Runaway can occur, whereby the heat generated cannot be dissipated, resulting in temperatures exceeding 1300˚C, hot enough to ignite any adjacent combustible materials. Prolonged electrical overload can have a similar effect, especially in relation to electrical intakes.

Unfortunately, existing circuit devices such as MCBs and RCDs offer no protection, as they are unable to detect heat generated at the points of connection. Similarly, regularly inspecting and testing the electrical installation (an EICR in the UK) does not necessarily provide protection, because it is primarily concerned with determining if the installation is electrically safe for continued use, rather than focusing upon the risk of an electrical fire. Given the recommended interval between inspections – and the fact that only a sample of the connected accessories, such as sockets, are routinely inspected – a resistive heating fault can easily develop unnoticed.

Thermal imaging using infrared cameras to detect ‘hotspots’ is another means of assessing the health of an electrical installation. However, the usefulness of such a survey is dependent upon all electrical loads being present at the time of inspection, as the survey only records a snapshot at that moment in time when the camera passes over the connection point.

Key features of Thermarestor

As a pre-ignition solution to the problem, Thermarestor represents a step change in fire safety. The majority of fire safety measures are post-ignition and seek to contain the effects of a fire. Thermarestor prevents such fires from happening in the first place. Key features of the system are as follows:

• Continuously monitors the circuit for signs of excessive heat
• If excessive heat is spotted, notifications can be sent to registered users as a maintenance issue warning which needs investigating – the fault causing overheating can then be rectified
• Notifications can be sent via an existing fire alarm or building management system, or as a standalone notification via text messages or email alerts
• Installation is straightforward and can be undertaken by a competent electrician. It can be installed new or retrofitted

The red Thermarestor strips located within the electrical cabinet continuously monitor heat levels

Predictive function

Thermarestor is important because it facilitates the sending of an alert to a third party prior to ignition, whereas most detection systems are post ignition. That is not to say that post ignition measures lack credibility, but if there is an opportunity to turn a potential fire into a maintenance issue, then this must be a good path to tread. The device thereby builds further fire safety into the whole dynamic by providing a predictive function.

The device is also important because it could provide the ‘missing link’ in the IOT dynamic, via sending early warning of developing problems to nominated individuals prior to ignition.

Case in point – Lithium-ion battery fires

Whilst the device has to date been used in a ‘traditional’ sense already outlined, there are new sectors which are being scoped. In particular, the PV Solar markets, where the protection of SCBs and Inverters is a moot point.

At present, the media coverage for Lithium-ion battery related fires is taking off, as it becomes clear the problem is only getting more serious.

The current ‘solutions’ seem to concentrate on better battery quality/BMSs and Lithium-Ion battery fire management. These focuses are crucial, of course, but this does not reflect the whole problem faced. Improved & more rigorous standards for Lithium-Ion batteries must be the aim – but this does not account for human error, battery damage (which is often ‘unseen’) and conditions in the real world – which are not always recorded in a book of standards/guidance.

Moreover, the Lithium-Ion battery industry is being investigated – for instance with charge/storage boxes for such batteries. We firmly believe that there is so much more that the device can do to help manage the harmful effects of a Lithium-Ion battery fire – and if not to actually prevent it – to provide warning that something is going wrong.

We are currently investigating the scope for potential with EVs in particular, as well as with battery charge/storage boxes.

WATCH: IFSEC Global’s recent webinar highlighting the causes, effects and possible solutions to lithium-ion battery fires is now available to watch on-demand, here >>

How to stop your trousers falling down…

A useful analogy which helps demonstrate Thermarestor’s role is that it helps your trousers stay where they are: safe, secure, also comfortable – and NOT ‘round your ankles! Perhaps think of Thermarestor as the ‘belt’ – with a fire tackling approach providing the ‘braces’. Well placed, the ‘belt’ could cut out a good proportion of these potential electrical fires (appropriate preventative or avoiding action then being taken) and those which evolved onto the ignition phase – perhaps not electrically caused at all – could be tackled by a range of existing means.

In terms of emphasis, the fire safety industry can sometimes appear to concentrate more on detecting and dealing with an existing fire than with its prevention. There are complicated reasons for this, but Thermarestor should help contribute towards righting this balance, so that more attention is given to trying to ensure that the fire does not start in the first place.

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