Passive Fire Protection – Unique Solutions For Unique Structures

In recent years commercial property design, especially in skyscrapers, has developed significantly as modern architects have pushed conventional boundaries to the limits.  We have seen a move away from straight lines and sharp angles, with rounded edges and curves becoming more commonplace.  Whilst these designs can look aesthetically stunning and have a striking impact on the local skyline, constructing them can prove more challenging than a traditionally shaped skyscraper.  Having recently worked on 20 Fenchurch Street, London, more commonly known as the ‘Walkie Talkie’, Sharpfibre understand just how an irregularly shaped structure can complicate the build project.

Assessing The Challenge

On the back of our successful 15 year relationship with Canary Wharf Contractors Limited (CWCL), Sharpfibre were asked to provide passive fire protection for 20 Fenchurch Street.  The 160 metre tall skyscraper, which was the brainchild of Uruguayan architect Rafael Viñoly, gets wider towards the top, giving the impression that it is bursting at the seams.  Sharpfibre were tasked with protecting the structural steelwork, totalling 80,000m², to 90 and 120 minutes. 

The build programme was tight, with our deadline demanding that we complete one of the 37 storeys every week.  The location of the site also meant that the build was subject to strict environmental controls, with the Corporation of London requiring regular air monitoring.  With a completely exposed building envelope, we also had to factor in high winds and driving rain; meaning the application had to be able to withstand anything that nature had to throw at it.  To further complicate matters, the unique shape of the structure meant that hoists and tower cranes were already in high demand for other areas of the construction. 

A Bespoke Solution

Having carefully considered every requirement, Sharpfibre realised that the most suitable solution was to apply Cementitious Fire Spray to the structural steel.  Not only is this solution fast to apply, thus allowing us to meet the tight deadline, it is also quick to cure, ensuring that it is not damaged by the elements. 

By building a bespoke mixing and pumping station on the ground floor, we were able to supply the entire building from one central location, with aluminium pipes delivering the Cementitious Fire Spray.  As a result, Sharpfibre’s requirement of access to the tower cranes and hoists was greatly reduced, allowing other areas of the construction to continue unhindered. 

In order to ensure that the strict environmental requirements were met and that the application was protected from the elements, we utilised our patented encapsulation system, which is constructed from fire retardant Monoflex sheets that are fastened to the building structure.  The approach served to neutralise the high wind speeds and also accommodated the unique geometry of the structure. 

The encapsulation system also has an internal connecting overlap, which can be partly released.  This allows for the floor to be cleaned, without operators disturbing the Cementitious Fire Spray surface, thus allowing work on each floor to be completed in one pass.  Having completed one floor, we were then able to transport the encapsulation system up to the next level and repeat the application process. 

Despite the unique challenge presented by 20 Fenchurch Street and a long cold winter with large amounts of snow, Sharpfibre were able to deliver the passive fire protection element of the project on time, completing our work in March 2013.  It was a great honour to work on such a distinctive building and play our part as Rafael Viñoly’s vision became reality. 

Anyone wishing to take a closer look at the structure will be able to do so once construction is fully completed in spring 2014, as the top 3 floors will be open to the general public.  These floors are to include sky gardens and a viewing deck, which will offer superb views of the London skyline and some other famous modern skyscraper designs, including The Pinnacle and the The Gherkin. 

Founded in 1987, Sharpfibre Limited is one of the UK’s leading passive fire protection contractors, offering clients a complete integrated solution, from structural steel protection, through to penetration sealing.