Fire strategy in construction design: why early decisions control risk, cost and compliance

Fire strategy gets treated as a late stage task on most projects. Submit it to Building Control, tick the box, move on. I have seen this on enough schemes now to say with confidence: that approach costs money, creates programme risk, and produces buildings that are compliant on paper but not in practice.

Get fire into the design process early and you control layout, services, and compliance from the start. Leave it late and you are reacting to decisions other people have already made.

What a fire strategy is actually for

It is a design tool, not a sign-off document.

At concept and developed design stage it should be fixing escape routes and travel distances, setting compartment lines and fire resistance periods, identifying protected shafts and risers, and aligning structure, layout and services in a way that can actually be built. If those things are not sorted early, every trade starts filling in the gaps with their own assumptions. That is where the problems begin.

Where most schemes go wrong

Structural failures are rare. Service and penetration failures are not.

The pattern I see repeatedly: large unplanned service routes through compartment walls, ceiling voids linking multiple fire compartments across a floor plate, poor sealing at wall head junctions, and inconsistent standards of fire stopping across different trades.

None of these are complex problems. They are coordination problems.

On several leisure and commercial schemes I have reviewed through Soldi, ceiling voids of 400mm to 600mm were left completely open across compartment lines. The structure was fine. The fire stopping was not. Smoke will travel through a void like that long before any fire resistance period becomes relevant.

Draw the compartment lines. Do not assume them.

“This is a 60 minute wall” is not enough.

You need drawings that show where the compartment line sits, details at junctions and wall heads, defined interfaces with structure and roof, and service routes agreed before anyone starts installing anything. If it is not drawn, it will not be built to any consistent standard.

My approach has been straightforward across UK projects: fix the lines at design stage, then coordinate every penetration against them. It removes guesswork on site and removes disputes at practical completion.

Fire doors are not a late specification item

They tend to end up in a schedule and get dealt with by a package manager who has not read the fire strategy. By the time someone is checking them on site the decisions have already been made.

What you need settled early: door types and ratings, locations tied to the compartment strategy, hardware and self closing requirements, and the management approach once the building is occupied.

The defects I see on site reviews are consistent. Doors wedged open. Incorrect gaps. Missing intumescent seals. Mixed ratings within the same protected route. These are not supply chain failures. They are design and coordination failures.

The cost case

Late fire input generates real cost. Opening up walls to install fire stopping that was missed. Re routing services that were installed without coordination. Upgrading partitions and doors to meet a standard the strategy should have set from the start. Programme delay.

Early coordination reduces rework, reduces variations, and reduces contractor disputes. That is where a consultancy like Soldi adds value, not by producing reports, but by reducing downstream cost through getting the decisions right before they become expensive to change.

What actually works

Fix compartment lines at concept stage. Coordinate services before installation. Define the ceiling void strategy early and make it part of the services coordination. Lock in fire door schedules and locations. Where there is any uncertainty about existing construction, carry out targeted intrusive checks.

That is not over design. It is basic coordination, done at the right time.

Final point

Fire safety in construction is not technically complicated. The failures are almost always simple and repeated. Late decisions create risk. Early decisions control it.

That is the difference between a building that is compliant on paper and one that actually performs.

Alex Petheram is Managing Director of Soldi Group, a fire safety engineering and construction risk consultancy based in Bath and London.