Lithium-ion batteries are now part of everyday construction life. From power tools and plant equipment to temporary lighting and handheld devices, battery-powered technology has improved mobility, reduced trailing cables and increased productivity across sites.
However, as adoption has increased, so too has a growing – and often underestimated – fire risk.
Understanding the Risk
Lithium-ion batteries store a high amount of energy in a small space. If damaged, overcharged, exposed to heat or faulty, they can enter thermal runaway – a rapid, self-sustaining chemical reaction that can result in intense fire or explosion.
Unlike conventional fires, lithium battery incidents:
- Escalate extremely quickly
- Burn at very high temperatures
- Are difficult to extinguish
- Can reignite after appearing to be out
On construction sites – where temporary electrics, combustible materials and high activity levels are standard – the consequences can be severe. Beyond the immediate danger to life, incidents can lead to significant asset damage, project delays and increased scrutiny from insurers and stakeholders.
Charging vs Storage: A Critical Distinction
It’s important to distinguish between battery storage and battery charging, as the risk profile differs.
Storage involves keeping batteries disconnected, protected from impact damage and segregated from ignition sources when not in use.
Charging, however, is an active electrical process. Energy is flowing into the battery, increasing internal temperature and placing stress on its components. If a defect exists, it is more likely to manifest during charging.
This is why many battery-related incidents occur not when tools are in use, but when batteries are left charging – often overnight, in welfare cabins, drying rooms or site offices.
Charging is not inherently unsafe – but unmanaged charging is.
The Growing Challenge of Unmanaged Charging
As more trades transition to cordless equipment, the volume of batteries on site has grown significantly. Multiple contractors may be charging equipment simultaneously, frequently in improvised or shared spaces.
Common site observations include:
- Charging taking place in combustible environments
- Batteries left unattended for extended periods
- Damaged or non-original chargers in circulation
- Overloaded extension leads
- No formally designated charging area
In many cases, these arrangements evolve operationally rather than being deliberately designed as part of the site’s fire risk assessment.
The result is increased exposure without clear ownership of the risk.
From a compliance perspective, this raises important questions. The Regulatory Reform (Fire Safety) Order and site-specific fire strategies require foreseeable risks to be identified and controlled. As lithium battery usage becomes routine, unmanaged charging is no longer an emerging issue – it is a known risk that requires proportionate control measures.
Safety and Productivity Are Not Opposites
There is also a practical dimension that is often overlooked.
When battery charging is organised, designated and properly managed on site:
- Downtime is reduced
- Trades are not waiting for partially charged equipment
- Batteries can be rotated efficiently
- Travel time to off-site charging points is eliminated
- Welfare areas remain clearer and more organised
In other words, structured charging arrangements do not simply reduce risk – they support operational efficiency and continuity.
Good fire safety practice and good site management should work together.
Moving from Awareness to Action
Lithium battery use is only set to increase across construction projects. The conversation is therefore shifting from whether batteries pose a risk, to how that risk should be managed proportionately and practically on live sites.
This is exactly what we will be exploring at our next Hot Topics event in London on 26 March. We will be discussing lithium battery fire risk in more depth and debating practical charging and storage solutions that are realistic for construction environments.
If this is an issue you are currently navigating – or one you anticipate becoming more significant across your projects – we encourage you to join the discussion.
Places are limited, and interest has been strong. If you would like to attend, please register your interest as soon as possible.
Call Howler on