;
The Great Fire of London
350 years ago the Great Fire of London destroyed most of the City, leaving thousands homeless as the fire spread rapidly through the urban sprawl of narrow streets and timber buildings. Out of the ashes emerged a new, more fire conscious approach to rebuilding the City, the lessons from the Great Fire of London are still as relevant to engineers, architects and city planners as ever before.
Commemoration: London1666
Arup was commissioned by public arts events charity Artichoke to enable ‘London1666’ the spectacular finale of their London’s Burning commemorative events, held to mark the 350th anniversary of the Great Fire of London.
‘London1666’, a 120 metre long wooden replica of the 17th century city skyline created by American ‘burn artist’ David Best, was set alight on the river Thames watched by thousands of spectators, with over 1million tuning into the live online broadcast.
Arup was appointed to provide fire and environmental advice for the project; a Total Fire Engineering approach in which fire risk is considered from concept stage, enabled the project to proceed. The key challenge for Arup’s fire engineers was to enable a highly controlled, prolonged and visually spectacular fire for Londoners to enjoy safely. The team carried out fire safety assessments, conducted testing and provided consultancy prior to the event to inform the planning committee of risk to spectators, property and the environment.
Creating a fire spectacle
Seeking to re-create the densely built London of 1666, the model comprised 137 buildings from 1m to 13m tall, arranged across two barges moored on the River Thames. The mainly plywood model was constructed on the barges, and displayed in the days leading up to the event, fire safety informed this phase as much as for the burn itself - ensuring public safety was fundamental.
The event itself, a 45 minute fire spectacle, fully achieved the artistic team’s ambitions, the flames visible from several hundred metres away lit up the structure, gradually consuming the model until the final collapse of the tallest buildings.
Arup is immensely proud to contribute to the commemoration of an event that shaped London as we know it today. Fire engineering this historic event was an opportunity to apply our first principles knowledge of fire safety and prevention to create a controlled yet spectacular fire.
Creating a fire spectacle
Arup fire engineering are experts at developing fire prevention and safety strategies, which requires a fundamental understanding of fire and smoke behaviour. Artichoke’s ‘London1666’ was a unique project, where unusually, a fire was actually required. We applied our expertise to deliver a highly controlled, prolonged and visually spectacular fire for safe public enjoyment.
Total Fire Engineering
Arup were appointed by Artichoke to provide fire and environmental advice at the earliest stage as understanding and addressing the risks were fundamental to the entire project. The enabling approach of Total Fire Engineering resulted in the spectacular event’s success.
The team carried out detailed analysis to establish appropriate fire and smoke scenarios, then led fire tests with Artichoke, which underpinned the numerical work. The resulting guidance was used to inform mitigation planning by the Licensing, Operations and Safety Planning Group.
Fire analysis: risks
The key challenge was understanding the extensive risks involved in creating a large fire in the centre of London, surrounded by spectators. In addition to mitigating risk factors, our fire engineers’ advice had to ensure that the resulting fire would provide a spectacular display.
Our assessment encompassed risks to people, the barges, surrounding buildings, and air quality, quantifying potential fire scenarios to inform how the model was constructed, and ignited.
Analysis included:
- Quantifying combustible material, advising on separation distances of the timber buildings, and witnessing fire testing to anticipate fire scenarios
- Investigating firebrand production and trajectory, and determining the effects of wind, including the risk of fire whirl
- Calculating radiation and heat transfer on the barges, and advising on safe distances on the Thames
- Advising on potential smoke quality, plume trajectory and concentration, with modelling by Arup’s air quality team.
Creating the fire
We advised the artistic and pyrotechnic teams on creating a model which would provide the visual effect required by developing an approach of flame sources, ignited using an electronic charge within a liquid fuel.
Flame source testing culminated in successfully demonstrating to London Fire Brigade and the artistic team that the approach was able to quantifiably provide the spectacle required without uncontrolled flame spread.
Conclusion
The Great Fire of London remains relevant to engineers, architects and city planners today, in the use of sustainable construction materials and managing the built environment.
Marking the 350th anniversary provides an opportunity to engage with these issues and further our understanding of fire. Arup Fire Engineering are continuously developing innovative solutions, tools and technologies required to mitigate fire risks.
““Modern methods of construction are changing and going back to being as combustible as they were then. All of those challenges at a city scale are starting to re-emerge.”
Dr Barbara Lane, Arup Fellow and Global Fire Leader ”
