52 Lime Street

Designed by architects Kohn Pedersen Fox, 52 Lime Street, also known as The Scalpel, is a 38-storey commercial skyscraper situated in London’s lucrative financial district. Located in the City of London cluster among the Leadenhall Building and The Gherkin, The Scalpel is an icon of the capital’s skyline and a stunning addition to London’s urban scene.

Ambar Kelly worked with main contractor, Skanska and frame subcontractors, Byrne Bros and William Hare on this project. Ambar Kelly’s patented system, RiserSafe®, was installed at every riser shaft opening on every level of The Scalpel to prevent the risk of falls from height and the spread of smoke and flame through the riser zone, keeping the subcontracting teams safe whilst work was undertaken.

RiserSafe® is a bespoke, prefabricated solution which provides 11 functions across a construction site, saving money, time and risk. RiserSafe® eliminates the risk of falling from height through floor openings by sealing the opening in one action, thus negating the need for additional project costs such as riser scaffolding and temporary hand rails.

On The Scalpel project, Ambar Kelly designed and manufactured 992 RiserSafe® units. The units were installed seamlessly and integrated perfectly with the M&E contractors single-storey prefabricated pipework modules. This level of efficiency streamlined project delivery and offered no delay to the work of other disciplines involved on the project. RiserSafe® incorporates up to 16 separate interfaces between the riser zone, coordinating the other disciplines which drives a project to an earlier completion date.

Ambar Kelly sent its smaller RiserSafe® units to William Hare’s factory so the units could be welded to the structural steel beams. The benefit of this process is twofold; one, the welded unit cantilevered off of the steel, eliminating the need for trimmer steels, and two, it reduced the crane lifts required for the RiserSafe® units themselves and the trimmer steels. This reduced the operations and crane lifts, thereby speeding up the programme.

As well as mitigating the risk of falls from height, RiserSafe® also enables horizontal fire protection, preventing the spread of smoke and flame in the event of fire during construction. RiserSafe® has been tested for 90 minutes at the British Research Establishment (BRE) with a temperature of 1000oC underneath without failure to its integrity. When used in conjunction with fire stopping compounds, RiserSafe® has been tested and shown to provide a 120-minute fire-rating for integrity and insulation.

As well as installing RiserSafe®, Ambar Kelly supplied 107 innovative plumbing hole units to facilitate the safe practice of site surveys. These units incorporated a system that eliminated the need for shuttering and propping the hole from below when finally concreted up.

The presence of Ambar Kelly and RiserSafe® assured the quick, safe delivery of The Scalpel’s structure, removing the risk of working at height and the spread of smoke and flame during construction.