70 St Mary Axe | Ambar Kelly
Ambar Kelly

70 St Mary Axe


Project Img
Client Mace Group
Main Contractor Mace Group
Type of Development New Build
Structure Concrete core & steel frame
Project Value £300m
Contract Value £306k

70 St Mary Axe, London

Famed for its parabolic shape, 70 St Mary Axe is a 22-storey building designed by Foggo Associates and situated adjacent to the iconic Gherkin.

Ambar Kelly worked with client and main contractor, Mace Group on this project. This 22-storey commercial building is of concrete core and steel frame construction, with risers around the outside of the concrete central core. Ambar Kelly’s innovative system, RiserSafe® had two roles – after handover it becomes the clients riser maintenance floor but during construction it prevents the risk of falls from height and the spread of smoke and flame through the riser zone, keeping the subcontracting teams safe whilst working on 70 St Mary Axe project.

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 BWIC, riser scaffolding and temporary hand rails.

Such was its success on the One Angel Court project, RiserSafe® was selected for 70 St Mary Axe as it perfectly complemented an updated riser strategy developed by the Mace Group. Mace Group’s main requirement was for the total riser strategy to be developed by the construction team from very early on in the design phase. RiserSafe® was approved by all stakeholders and was subsequently used across the project.

Mace Group purchased the units directly and free-issued them to the steel frame contractor, VBH JV (a joint venture of Hollandia and Victor Buyck). Some of the units were 7m x 1.5m wide which Ambar Kelly designed to incorporate horizontal fire protection and drylined fire walls as part of the RiserSafe® system. This allowed for a group of shafts, or openings, to be combined into one unit, which reduced the number of trimmer steels and concrete beams required for walls, thereby reducing crane lifts and construction time.

Another advantage was the reduction in temporary fire doors required in risers. RiserSafe® has been tested for 90 minutes at the British Research Establishment (BRE) with a temperature of 1000oC underneath without failure to its integrity. This means that when the riser shaft is closed with RiserSafe® the risk of the spread of smoke and flame through the hole is eliminated which in turn means that temporary fire doors to risers do not need to be procured for the construction phase. 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 removing the risk of working at height, the presence of RiserSafe® also eliminated the potential spread of smoke and flame during construction, created multiple work fronts to speed up the programme before becoming the client’s riser maintenance floor. Together this has proved that Ambar Kelly’s patented system can hit the mark on quick project delivery, cost savings and most importantly, safety.

Client feedback: “I would say that my experience of riser safe on 70SMA has been very positive.”

Photography: Courtesy of James Reid Photography.