Lithium-ion battery charging at work: what employers need to control

Why lithium-ion battery charging has become a workplace issue

Many businesses have never formally decided whether employees may charge personal e-bikes, e-scooters or power banks at work. Devices simply appear beside desks, in stockrooms, under stairs or near staff entrances. Workshop batteries may be placed on charge at the end of a shift, while delivery riders or mobile workers bring higher-capacity batteries indoors.

That informal approach leaves important questions unanswered. Is the battery undamaged and the charger compatible? Could a fire block an escape route? Would anybody notice warning signs before the premises were empty?

The risk is locally relevant. Tyne and Wear Fire and Rescue Service's Community Risk Profile 2025–2030 records 19 e-bike or e-scooter fires between April 2022 and March 2025, with nine occurring while charging. It reports 11 people injured across seven e-bike or lithium-ion battery fires. The figures are not workplace-only, but they demonstrate the risk.

What is thermal runaway?

Thermal runaway is a chain reaction inside a battery cell. Heat is generated faster than it can escape, the cell temperature rises and neighbouring cells can also begin to fail. The battery may then release flammable and potentially toxic gases, ignite or explode.

Poor manufacture, impact damage, water ingress, overheating, modification, incompatible components and charging outside the manufacturer's limits can increase the risk. A battery can therefore appear to be a simple electrical item while storing enough energy to create a fast-developing incident.

Government guidance says the risk is highest while e-cycle and e-scooter batteries are charging. Complete systems from established brands, bought from reputable retailers and used as instructed, are understood to present a low fire risk. The objective is proportionate control.

An updated fire risk assessment is not optional

This is the starting point, not an administrative afterthought. Premises within the Regulatory Reform (Fire Safety) Order 2005 should already have a suitable and sufficient fire risk assessment. Introducing lithium-ion battery storage or charging—or materially changing its scale, location or operating hours—means that assessment must be reviewed and, where the hazard or consequences have changed, updated before the arrangement is accepted. A note saying ‘electrical equipment present’ is not enough.

That does not always mean commissioning a completely new report from page one. It means the existing fire risk assessment must be revisited by a competent person and amended so it genuinely addresses the new hazard. If the current assessment is missing, out of date, generic or unsuitable for the building, a full new fire risk assessment may be required rather than a short addendum.

The updated FRA should identify the batteries and chargers, quantities and energy capacity, ownership, charging locations and hours, people at risk, ignition and fire-spread potential, effects on escape routes, detection and alarm coverage, electrical isolation, supervision, firefighting strategy, emergency response and actions with named owners and completion dates. It should also test whether the building’s existing fire strategy remains credible if a battery fails where charging is proposed.

Where no suitable battery-specific assessment exists, complete a dedicated lithium-ion battery charging and storage assessment and cross-reference it within the main FRA. That supporting assessment does not replace the statutory FRA. Its material findings must be incorporated into the FRA, fire strategy, emergency plan, staff instructions and inspection regime.

Electrical safety duties also remain relevant. HSE advises employers to assess electrically powered equipment, confirm that it is suitable for the intended use and supply, keep it in good condition and ensure users are trained. A sticker from a periodic portable-appliance test does not prove that a damaged battery, unsuitable charger or poor charging location is safe.

RC59—or another suitable charging assessment—must support the FRA

RC59: Recommendations for fire safety when charging electric vehicles is insurer-led good-practice guidance developed through RISCAuthority and published by the Fire Protection Association. It provides a useful structure for assessing EV charging locations and considering passive, active and managerial controls. It is not legislation, a statutory certificate or a substitute for the premises fire risk assessment.

For electric cars, vans, motorcycles and other vehicles within its scope, an RC59-based assessment should be considered wherever charging is proposed—particularly in enclosed or underground car parks, beside buildings, below sleeping accommodation, near combustible façades or where fire could affect escape or firefighter access. The findings should be incorporated into, or appended to and clearly linked from, the FRA. The assessor should also check insurer requirements, the electrical installation, manufacturer information and any relevant fire strategy or building-control constraints.

Scope matters. Government premises guidance notes that e-cycles and e-scooters may fall outside RC59’s scope, although its risk-control principles may still assist. For e-bikes, e-scooters, portable tools, cleaning equipment, mobility devices or larger battery-energy storage, use a suitable equipment- and premises-specific assessment supported by the relevant government, sector, electrical and manufacturer guidance. Calling every battery review an ‘RC59 assessment’ risks suggesting that one document covers every battery use.

The defensible approach is therefore: update the statutory FRA; complete an RC59-based assessment where EV charging is within scope; use another competent, battery-specific assessment where it is not; and ensure every material finding is reflected in the building’s actual controls.

HRBs and other high-consequence buildings require greater scrutiny

In England, an occupied higher-risk building under Part 4 of the Building Safety Act is generally at least 18 metres high or seven storeys and contains at least two residential units. A new charging proposal in such a building should be raised with the accountable person or principal accountable person. Its effect on the fire strategy, building-safety risk assessment, safety case, resident information and golden-thread records may need to be considered—not only the local socket and charger.

If providing the charging facility involves building work to an HRB, the client must establish the correct Building Safety Regulator approval route before work begins. Work involving passive fire protection, alarms, sprinklers, escape routes or common parts can be Category A work. Government guidance also requires surveys, inspections or building-information checks to evidence the effect of proposed work rather than relying on assumptions.

Care homes and hospitals need equally serious attention even though buildings used entirely for those purposes are excluded from the Part 4 in-occupation HRB regime. They can be within the HRB design-and-construction regime, and their occupants may be asleep, dependent on staff assistance, have limited mobility or cognition, use oxygen or powered medical and mobility equipment, or require progressive horizontal evacuation. Supported or sheltered accommodation can also fall within the in-occupation HRB regime where the legal height and residential-unit tests are met.

The same higher-consequence approach may be appropriate in hotels, hostels, student accommodation, prisons, schools with sleeping accommodation, heritage buildings, multi-occupied residential blocks, basements and premises with difficult evacuation or large numbers of people. Legal HRB status is not the only indicator of risk.

The FRA should consider both the charging hazard and the real evacuation strategy. Controls may include external charging, a suitably fire-resisting hazard room, enhanced automatic detection, controlled electrical isolation, limits on battery numbers and capacity, supervised charging, formal approval of personal mobility equipment and a safe quarantine route for defective batteries. Charging in bedrooms, corridors, stairs or protected escape routes should not be accepted simply because it is convenient.

Could a fire compartmentation survey be required?

Yes—sometimes. The ordinary FRA is primarily a risk assessment and is usually non-destructive. It may identify that the safety of the proposal depends on walls, floors, ceilings, risers, service cupboards, fire doors or fire-stopping providing a known period of fire resistance. If reliable plans, specifications, inspection records and visible evidence do not confirm that protection, the assessor should not simply assume the compartment is sound.

A targeted fire compartmentation survey may then be required. This can range from inspection of accessible areas to a more intrusive survey opening selected concealed locations. The scope should be proportionate and defined by a competent fire-safety professional, particularly where a charging room sits below or beside sleeping accommodation, where cables or ventilation penetrate compartment lines, where previous alterations are undocumented, or where defects could allow smoke and fire to spread into escape routes or adjoining occupancies.

The survey is not an automatic add-on for every laptop, tool charger or e-bike. It becomes necessary when the FRA cannot reach a reliable conclusion without evidence of passive fire protection, or when the proposed control measure depends on compartmentation being effective. Any intrusive inspection must be planned, authorised and followed by competent reinstatement of openings and fire-stopping.

For HRBs, the need for surveys and the findings should be coordinated with the accountable persons and captured in the building’s information and change-control arrangements. If the proposal affects external walls, a separate fire-risk appraisal of external walls may also be relevant; that is a different question from an internal compartmentation survey.

Start by finding out what is being charged

Before writing a policy, establish what is already happening. Speak to managers and employees, inspect likely charging locations and include contractors, cleaners, delivery workers and others who may bring battery-powered equipment onto the premises.

Record the types and numbers of devices, their ownership, normal charging times and whether charging continues when the building is unoccupied. Higher-capacity batteries, modified e-bikes, conversion kits and equipment of uncertain origin need particular attention.

Then decide what the business will permit. An office may prohibit e-bike charging indoors, while a workshop may authorise specified tool batteries in a designated area. A delivery business may need purpose-designed facilities.

• Require manufacturer-approved or demonstrably compatible chargers.
• Do not permit visibly damaged, swollen, leaking or unusually hot batteries onto the premises.
• Prohibit unauthorised modification, repair or makeshift charging arrangements.
• Identify who can approve new equipment and who monitors the charging area.
• Set rules for charging outside occupied hours based on the fire risk assessment.

Choose the charging location carefully

Location can determine whether a battery failure remains a contained incident or prevents people from escaping. Do not allow charging in corridors, stairwells, entrance lobbies or other places where smoke, heat, the device itself or firefighting activity could compromise an emergency route.

The government's premises guidance describes separate, secure charging facilities as the best solution where the scale justifies them. It suggests purpose-designed metal lockers, ideally outside, and highlights detection, ventilation, electrical isolation and firefighter access.

For simpler arrangements, use a designated area on a stable, hard surface, away from combustible stock, waste, aerosols, flammable liquids and heat sources. Provide enough fixed sockets to avoid daisy-chained extension leads or adaptors. Check the manufacturer's instructions and obtain competent electrical or fire-safety advice where the quantity, battery size, premises layout or overnight charging increases the risk.

Train people to recognise a battery that may be failing

Warning signs can include unusual heat, swelling, bulging, leaking, discolouration, a chemical smell, hissing, cracking, smoke or a charger that repeatedly becomes abnormally hot. Staff should know that these signs require immediate action, not another attempt to charge the device.

The procedure should tell people to stop using the equipment, raise the alarm and move away from danger. They should only disconnect power or relocate equipment when this can be done safely and the approved procedure allows it. A smoking, hissing or rapidly heating battery can deteriorate quickly; staff should not improvise or carry it through an occupied building.

Damaged batteries also need a controlled storage and disposal route. Do not place them in general waste or leave them on a bench for somebody else to deal with. Follow the supplier's advice and use an appropriate battery or hazardous-waste service.

Make the emergency plan match the risk

Employees need a simple response: raise the alarm, evacuate, close doors where safe and call 999. Nobody should be expected to tackle a lithium-ion battery fire unless the risk assessment, training and equipment specifically support that role. The priority is getting people out and giving the fire and rescue service accurate information about the battery type, location and quantity.

Check that detection covers the charging location and the alarm can be heard throughout the premises. Consider lone workers, overnight charging and periods without normal supervision. Emergency information should identify isolation points and prevent re-entry.

A practical lithium-ion battery charging checklist

The finished policy should reflect the equipment and premises rather than reproduce generic internet rules. Controls suitable for two laptop chargers in a Stockton office will not be enough for a Gateshead warehouse charging multiple tool batteries or a Newcastle delivery hub accommodating e-bikes.

• Survey which lithium-ion batteries are stored or charged on the premises.
• Arrange a competent, documented FRA review before introducing or materially changing charging, and update or replace the FRA where necessary.
• If the existing assessment lacks detail, complete a dedicated charging assessment and link its findings back to the fire risk assessment.
• Use an RC59-based assessment within its EV-charging scope, or another suitable battery-specific assessment where RC59 does not apply.
• For an HRB, involve the accountable person or principal accountable person and establish whether BSR approval or formal change control is required before building work starts.
• Decide whether the FRA needs evidence from a targeted or intrusive fire compartmentation survey rather than assuming fire-resisting construction is sound.
• Apply enhanced, occupancy-specific controls in care homes, hospitals, supported living and other high-consequence premises.
• Keep charging away from escape routes and combustible materials.
• Use genuine, compatible batteries and chargers from reputable suppliers.
• Provide sufficient suitable sockets and avoid makeshift adaptors or overloaded extensions.
• Introduce a clear process for inspecting and reporting damage or unusual heat.
• Decide whether unattended or overnight charging is permitted.
• Provide safe storage and an approved disposal route for defective batteries.
• Check detection, alarm, evacuation and electrical-isolation arrangements.
• Train staff, monitor compliance and review the controls after any change, defect or incident.