Electric vehicle charging in enclosed car parks

Parking policy tells you to put charge points in the basement car park. Fire evidence tells you to think hard about where. Those two instructions arrive from different parts of the same authority, and on an EV charging basement car park the applicant is the one who has to reconcile them before the application goes in rather than after the consultation responses land.

The short version. Building Regulations Part S requires charging infrastructure for new residential development with associated parking, local policy often requires more, and neither regime tells you how to lay out an enclosed car park so that a vehicle fire does not become a building fire. That part sits with the fire engineer, and its consequences land on the planning drawings.

Why enclosed parking attracts the scrutiny

A vehicle fire in an open deck car park vents upwards. The same fire in a basement or a fully enclosed podium has nowhere to go, so heat builds against the soffit, smoke fills the level, and the structure above is loaded in a way an open deck never is.

Lithium-ion batteries add two features fire services care about. Thermal runaway can propagate cell to cell, which extends the burn time well beyond a conventional vehicle fire. And extinguishment takes sustained water application rather than knockdown, so the water supply and the drainage arrangement both matter.

None of that makes charging in a basement unacceptable. It makes the layout, the ventilation and the management arrangements part of the planning conversation instead of a detail left to building control.

Policy asks for charge points, evidence asks for care

Part S of the Building Regulations, in force since June 2022, sets the baseline for new residential buildings with associated parking and for major renovations, covering both installed charge points and cable routes for later installation. Local policy frequently goes further. The London Plan sets out active and passive charging provision for residential parking, and many authorities outside London carry a similar requirement in an adopted parking standards document.

So the provision is not optional and the quantum is usually fixed by policy. What remains within your control is placement, the servicing arrangement and the management regime, and those are what a fire engineer will want to influence.

Treat the parking layout as a fire question from the first sketch. Retro-fitting a charging strategy into a basement designed purely around space counts and ramp gradients is the expensive version of this exercise.

Where the charge points sit in the layout

Four placement principles come up on almost every scheme.

Keep charging bays away from the sole protected stair and from the lobby that serves it, so that a fire at a charging bay does not compromise the escape route or the firefighting access.

Keep them off the structural elements that carry the building above where you can, because localised prolonged heating of a transfer structure is a different problem from heating a slab.

Put them where the ventilation works hardest, which usually means near the ramp or the ventilation openings rather than in a dead-end bay at the far corner.

And group them, rather than scattering single points through the level. Grouping concentrates the risk in a place you have designed for and simplifies detection, suppression and signage. It also makes the electrical distribution cheaper, which is the one part of this that the client will enjoy.

An illustrative case. A hypothetical basement under a seven storey residential block has 40 spaces, a single ramp and two cores. Scattering 8 active charge points across the level puts two of them in the lobby approach to the eastern core. Grouping all eight against the ramp wall, on the far side of the level from both core lobbies, gives a defensible layout without losing a space. Illustrative, and it would still need testing by a fire engineer.

Ventilation, detection and suppression

Approved Document B's guidance for enclosed car parks works on ventilation openings sized as a proportion of floor area at each level, or a mechanical alternative expressed in air changes per hour. Check the current edition rather than a remembered figure, because the guidance for car parks has been under review alongside the wider Approved Document B revisions.

Beyond the baseline, expect three questions.

Whether the car park is sprinklered, and if so whether the design density accounts for a prolonged vehicle fire rather than a standard warehouse scenario.

How smoke is cleared for firefighting after the fire, which is a different design case from smoke control during escape.

Whether detection at the charging bays is separate from the general car park system, so that an incipient battery event raises an alarm before it becomes visible.

These are all Fire Safety Strategy matters. What the planning application needs is confidence that the strategy exists and that the layout it implies is the layout being applied for. The same logic applies to structure: whether the frame is designed as a Class 2B or Class 3 building changes what a localised failure does, and the note on disproportionate collapse and building class sits alongside the fire case.

Management, monitoring and who holds the plan

A basement charging installation needs an owner. On a build-to-rent or managed block that is straightforward. On a scheme sold off plan with a management company set up later, it is the part that gets forgotten.

The arrangements worth writing down are who inspects the equipment and how often, what happens when a vehicle shows a fault, whether charging is restricted overnight when nobody is on site, how the fire service is given information about the location and isolation of the charging supply, and how damaged or recalled vehicles are dealt with.

Authorities increasingly ask for this as a document rather than a paragraph, and it is easier to write once than to produce under condition discharge with a completion date approaching.

What the fire statement should say

If the building meets the height or storey condition for a relevant building, the application needs a fire statement on the prescribed form under Article 9A of the Development Management Procedure Order 2015, and the Health and Safety Executive will be consulted.

The Fire Statement is short, so use the space well. Say where the charging bays are and why. Say how the car park is ventilated in principle. Say how fire service access to the basement works, including where the appliance stands and how far the entry point is from the charging group. Say what the evacuation strategy is for the building above and whether a car park fire changes it.

What it should not do is promise a suppression system or a detection specification that the fire engineer has not yet confirmed. An overreaching fire statement becomes a condition you then have to vary.

Conditions and future-proofing

Expect conditions requiring a fire safety management plan for the car park before occupation, requiring the charging installation to be provided in accordance with an approved drawing, and sometimes restricting later increases in active charge points without further approval. That last one matters, because passive provision exists precisely so that active points can be added as demand grows.

Ask for the condition to be drafted around a maximum number of active points and an approved layout zone rather than a fixed drawing, so that adding points within the designed area does not need a new application. Where the building also has a basement, the ground conditions work in the Basement Impact Assessment should be coordinated with the fire and ventilation design, because ventilation shafts and escape routes both compete for the same structural openings.

This is general guidance, not legal advice. Check the position with your local planning authority, your building control body and a qualified fire engineer before relying on it. For fire statements and fire safety strategies a competent fire engineering author is legally required, and an AI-assisted draft is a starting point for that professional rather than a substitute.

Browse the PlanScope report types to see which fire and structural documents a basement scheme is likely to need. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.