Fire Strategy for Car Parks

What makes car park fire strategy technically distinct

Car parks are a building type with a specific and well-established fire safety engineering framework that differs substantially from most other buildings. The fundamental question the fire strategy must answer is whether the car park qualifies as open-sided under the definition in Approved Document B — which depends on the proportion of each storey's perimeter that is open to the outside air. An open-sided car park benefits from natural ventilation that limits smoke accumulation, which removes the requirement for mechanical smoke ventilation and reduces the structural fire protection requirements. An enclosed car park requires a mechanical smoke ventilation system designed to maintain a clear layer for escape and firefighting.

The increasing prevalence of electric vehicles has introduced a significant new consideration for car park fire strategy. EV fires produce intense heat, burn for extended periods, and are resistant to suppression by conventional means. The fire strategy must address how an EV fire is managed in the context of the car park design: whether the structural elements and compartmentation are adequate to contain a prolonged burning vehicle, whether the smoke ventilation system is designed for the heat output of an EV fire, and whether dedicated EV charging bays require additional fire engineering measures. National guidance on EV fire safety in car parks is evolving, and the fire strategy must reflect current best practice.

The primary standards for car park fire strategy are Approved Document B and BS 7346 (components for smoke and heat control systems), alongside BS EN 12101 for smoke ventilation system design. The open-sided classification criteria in Approved Document B are critical, as they determine the entire fire engineering approach for the building. Where EV charging is provided, emerging guidance from the National Fire Chiefs Council (NFCC) and the Home Office's own guidance on EV fire safety must also be addressed. For multi-storey car parks above ground, structural fire protection requirements follow from whether the car park is open-sided or enclosed, with significant implications for the choice of structural frame and floor construction.