The Design Change Problem in Fire Safety

Design changes arising from unresolved fire safety issues are one of the most significant and avoidable sources of cost and programme delay on UK development projects. They are avoidable because every issue that causes a late-stage redesign could have been identified and resolved earlier — at a fraction of the cost — if fire engineering had been properly integrated into the design process from the start.

The Most Costly Fire Engineering Design Changes

• Escape stair repositioning: Moving or adding escape stairs at Stage 4 or later affects structural design, mechanical services routes, architectural planning and construction programme. One of the most expensive and disruptive changes possible
• Compartmentation in structural elements: Where fire compartment walls need to be added to a structural system that was not designed to accommodate them — requiring structural redesign and potentially affecting steel or concrete specifications
• Facade redesign for external fire spread: Discovering that a proposed facade system contains combustible materials at late design stage can require complete facade redesign — with programme and cost implications that can run into the millions
• Sprinkler system addition: Retrofitting sprinklers into a design that was not planned to accommodate them — with implications for ceiling void depths, plant room space and structural loading
• Smoke control system addition: Adding smoke control to a building where insufficient ceiling void depth or shaft space was provided

Case Study: The Cost of Late Discovery

A typical example: a 200-unit residential development at RIBA Stage 4 discovers that the proposed travel distance from units at the end of a double-loaded corridor exceeds the ADB limit of 7.5 metres (for dead-end situations). The solutions are: add a second stairwell (structural and programme impact), install sprinklers (additional cost), or redesign the corridor arrangement (architectural impact). Each solution costs significantly more than the few thousand pounds it would have cost to identify and resolve the issue at Stage 2.

How Early Fire Engineering Prevents This

A RIBA Stage 2 fire engineering review — typically half a day to a day of a chartered fire engineer's time — identifies these issues when they are still design options rather than construction problems. The fire engineer checks travel distances against the proposed layout, flags potential compartmentation issues, identifies external wall fire spread risks, and advises on sprinkler and smoke control implications. This information allows the architect to adjust the design before it becomes embedded in detailed drawings and specifications.