BESS fire safety in the UK: What commercial and industrial operators need to know

One of the biggest concerns that is often touted around battery energy storage systems all comes down to one thing – fire safety. 

On a regular basis, we see projects rejected by local councils on fire safety grounds, and that can have a detrimental impact on the industry’s progress towards the Government’s ultimate goal of achieving 23 to 27 GW of installed battery storage capacity by 2030. 

Despite the fact fire safety comes up as a concern time and time again, the UK lacks one neat BESS fire-safety rulebook, but that doesn’t mean the obligations are vague. We’ve gone through the guidelines and looked at best practices to hopefully help cut through the jargon and ensure more projects get online. 

No single rulebook does not mean no rules

For commercial and industrial operators, the first thing to understand is that BESS fire safety is not just a product compliance question.

Buying a certified battery system is important. It is not enough.

The Health and Safety Executive makes clear that designers, installers and operators need to consider duties under health and safety law, dangerous substances regulations, the Electricity at Work Regulations and related requirements. It also highlights the need to notify the local fire and rescue service where a site holds 25 tonnes or more of dangerous substances.

That means the operator has to understand the risk created by the installation, not just the rating on the battery container.

That includes:

• Where the BESS is located;
• What it is close to;
• How faults are detected;
• How gases are managed;
• How fire spread is limited;
• How the fire service can approach the site;
• Who owns the emergency plan;
• and how the system is inspected and maintained once it is live.

This is where projects can go wrong. Fire safety gets treated as a planning appendix, when it should be part of the site design from day one.

Planning is where many projects first feel the pressure

In England, the clearest BESS-specific planning signal is the 1 MWh lithium-ion threshold. For non-residential lithium-ion BESS of 1 MWh or above, national planning guidance encourages applicants to engage with the local fire and rescue service before submitting an application. It also encourages planning authorities to consult the fire and rescue service during determination.

But the wording there matters – it’s guidance rather than a hard statutory duty. That has led some to not see it as a requirement. The problem is, in practice, it’s starting to become a basic expectation. 

If the fire and rescue service only sees the project after the layout is fixed, the developer may already have created problems. Access routes may be poor. Cabinets may be too close to boundaries, buildings or other equipment. Drainage and runoff may not have been considered. Water supplies may be unclear. Emergency information may be generic.

At that point, ‘fire safety’ becomes the reason a project stalls.

Good operators will not wait for that to happen. They will engage early, while the site layout can still change.

Installing BESS within a building needs particular care

While much of the focus is often on outdoor containerised systems on an industrial site, they are not quite the same as a battery room inside a warehouse, factory, depot, office building or plant area. The closer the BESS gets to occupied buildings and critical operations, the more the fire strategy has to deal with escape routes, compartmentation, smoke and gas movement, access for firefighters and safe isolation.

Approved Document B, which is the building regulation in England covering fire safety matters within and around buildings, is not a BESS manual. It is still built around wider fire safety outcomes, such as warning and escape, limiting fire spread, and providing access and facilities for the fire service. But if a BESS sits within or forms part of a building project, those outcomes still have to be met.

This is a key point for commercial and industrial operators. A battery used to support EV charging, site resilience or peak shaving may look like an energy asset on a spreadsheet. In design terms, it may also be a fire load, a source of flammable gases, a constraint on escape strategy and a new maintenance responsibility.

That needs to be recognised before procurement, not discovered during handover.

The real control measures are practical

The technical guidance can feel dense, but the underlying questions are fairly practical:

• Can a fault be spotted early?
• Can the affected part of the system be isolated?
• Can gases escape or be managed safely?
• Can a fire be contained to one cabinet or container?
• Can the fire service get close enough to do what the plan says they will do?
• Can water and contaminated runoff be controlled?
• Does the operator actually know what to do when an alarm comes in?

DESNZ’s guidance on grid-scale electrical energy storage looks at safety across the full life cycle: design, planning, transport, installation, commissioning, operation, maintenance and end of life. It also points to hazards including thermal runaway, arc flash, toxic gases, flammable gases and cascading failure.

That lifecycle approach is the right one. BESS fire safety is not solved at planning. It has to survive commissioning, operation, maintenance and future modification.

Where this usually goes wrong

The first common mistake is treating the fire strategy as a document rather than a design input.

A consultant writes a report. The project team files it. But the actual site layout, access routes, alarm strategy and maintenance arrangements do not really change.

That will not stand up well if the project is challenged.

The second mistake is relying too heavily on the battery management system. The BMS matters, but it should sit within a wider monitoring and alarm strategy. Depending on the installation, that may also mean temperature monitoring, gas or vapour detection, audible and visual alarms, remote monitoring and clear escalation procedures.

The third mistake is assuming suppression is the answer to everything. Fire suppression has a role, but it cannot compensate for poor spacing, poor access or a weak emergency plan. National Fire Chiefs Council (NFCC) guidance makes clear that fire strategy should be based on the specific battery technology, site layout and likely incident scenario.

The fourth mistake is forgetting the operator.

A BESS project may be designed by one party, installed by another, maintained by a third and operated by a site team that had very little involvement in the original design. That is a recipe for confusion unless the handover is clear.

Someone needs to know what alarms mean, who can isolate the system, when to call the fire service, what not to open, where emergency information is stored and how damaged batteries will be dealt with after an incident.

What good looks like

A good BESS fire strategy starts early.

It begins with site selection and layout. The project team should be asking where the battery sits in relation to buildings, boundaries, transformers, switchgear, roads, vegetation, public access and critical operations.

It then moves into procurement. Operators should ask suppliers for evidence, not just reassurance. What standards has the system been tested against? What fire scenario has been assumed? What happens during thermal runaway? How is propagation limited? What alarms are provided? What remote monitoring is available? What maintenance regime is required?

Then comes commissioning. This is where too many projects are still too light. Alarms should be tested. Isolation should be demonstrated. Monitoring should be proven. Emergency contacts should be checked. Fire-safety information should be handed over to the people who will actually manage the asset.

Finally, there is operation. Inspection, maintenance, firmware updates, abnormal-event review, contractor competence and emergency drills all matter. A battery system that was well designed on day one can become a poor risk if no one owns it properly after energisation.

A practical checklist for C&I operators

Before planning, ask:

• Have we spoken to the local fire and rescue service early enough?
• Does the site layout allow safe access, separation and firefighting activity?
• Are neighbouring buildings, boundaries and public areas properly considered?
• Is the emergency response plan site-specific, or just a generic template?

Before procurement, ask:

• What evidence supports the supplier’s fire-safety claims?
• How does the system detect early faults?
• How are gases, heat and propagation managed?
• What are the inspection and maintenance requirements?
• What assumptions does the system make about remote monitoring and connectivity?

Before energisation, ask:

• Have alarms, isolation and monitoring been tested?
• Does the operator know what each alarm means?
• Are emergency contacts, drawings and site plans up to date?
• Are isolation points clearly marked?
• Has the fire-safety information been handed over properly?

During operation, ask:

• Who owns the fire-risk assessment?
• Who reviews changes to software, controls or site layout?
• Are maintenance records complete?
• Are contractors competent to work on the system?
• Has the emergency plan ever been exercised?

The bottom line

The UK’s BESS fire-safety regime is not especially tidy. That is inconvenient, but it is not an excuse for vague projects.

For commercial and industrial operators, the safest approach is to treat fire safety as a delivery discipline. It affects where the system goes, what gets bought, how it is commissioned and who owns it in operation.

The projects most likely to run into trouble are the ones that leave those questions until the end.

The projects most likely to get built, insured, commissioned and operated well are the ones that can show a clear chain of evidence: the risk was understood, the design responded to it, the system was tested, and the operator knows what to do when something goes wrong.

That is not just better fire safety. It is better project delivery.