Services

A fire strategy is a document that everyone else typically designs to. It outlines what is trying to be achieved in the design, how it is being achieved, and what systems are needed to implement it, such as: automatic fire detection and alarm, evacuation lifts, public address voice alarm systems, signage, emergency power supplies, compartmentation, structural fire resistance, space separation to boundaries and access for the fire service.

At handover it becomes part of the fire safety information passed to the owner under Regulation 38.

We review the available documentation against the drawings and against the guidance it (typically) says it follows, then check the approaches. Often, we see a disparity between a document and the drawings that highlights potential co-ordination shortfalls.

With modelling we look at the inputs before the outputs: the design fire, soot yield, mesh, occupant numbers, pre-movement times etc. Most challenges tend to start in these assumptions.

We start with what exists, such as the drawings, any fire strategy, fire risk assessments, O&M information and building control records. Then we examine whether the building appears to align with the paperwork. Often it doesn’t, usually because the fire strategy (if available) was never updated during later design stages and construction.

The report sets out what risks, challenges and opportunities may be available, and often, whether certain issues may need immediate corrective action by the responsible person under the Fire Safety Order.

CFD (computational fluid dynamics) is often used to help model the movement of smoke and heat through a space. Evacuation modelling simulates people moving to and through the exits. Together they can help inform on the time occupants may have before conditions become untenable.

A model is only as good as its scenario, so we seek to agree the design fires, occupancy and acceptance criteria with key stakeholders before running anything. The result is intended to inform whether it meets a performance criteria, whether it contains a margin of safety, and roughly by how much.

Policy D12 of the London Plan asks every development proposal to show how it achieves the highest standards of fire safety, and asks major developments for an independent Fire Statement. Policy D5 expects at least one lift per core to be a suitably sized fire evacuation lift wherever lifts are installed. Both affect the design early.

We write the statement to demonstrate that the strategy is feasible and that space has been allowed for stairs, lobbies, fire service access and water supplies. The statement is only an instrument, and in our view, should only be undertaken with a RIBA Stage 2 or 3 fire strategy developed in harmony to underpin it.

If a scheme would need a Planning Gateway One fire statement, it’s a higher-risk building and outside what we take on.

Approved Document B and British Standards are guidance. The Building Regulations set functional requirements, and there’s more than one way to meet them. We often use the framework within BS 7974 to examine and justify a specific departure from guidance or a certain design direction.