8 Bishopsgate is a 50-storey, 204-metre-tall skyscraper in the City of London, prominently situated on the corner of Bishopsgate and Leadenhall Street. Developed by Stanhope for Mitsubishi Estate London and designed by Arup and Wilkinson Eyre, the building has been awarded the top efficiency class EPC A rating as well as BREEAM Outstanding certification. Solar panels on the roof generate sustainable electricity. Urban planting on roof terraces and throughout the building provides a high level of biodiversity and comfort. The double-skin active facade minimises the building's CO₂ footprint and the need for air conditioning – as do the building’s special steel skeleton, solar control and low-e glazing from AGC Interpane Architectural Glass, and light-controlled shading.

The City of London financial district continues to impress with new buildings that are particularly notable for their excellent sustainability. One fine example is 8 Bishopsgate, a mixed-use office building featuring biodiverse green outdoor terraces, a 200-seat auditorium and a public viewing gallery – The Lookout – that crowns the 50-storey building. The stepped profile maximises lettable space while protecting views of the cathedral. To enhance the visual stacking effect, each block cantilevers from the west facade and is slightly rotated and taken out of plane. This approach creates a dynamic and playful arrangement that responds well to the varying building heights and shapes of the surrounding cityscape. It is also responsible for the building's nickname: ‘the Jenga tower’.

Smart glass facade for comfort and energy efficiency

Each of the main architectural elements of 8 Bishopsgate has a distinctive character. The lower block is clad in natural stone and has large square windows, while the middle and upper blocks are fully glazed. These glass facades were fitted with ipasol Bright LR (featuring a light-reflective coating) and iplus thermal insulation glazing from AGC Interpane Architectural Glass. The main product used until midway up the building, where the second block ends in a spacious roof terrace, is iplus 1.0 thermal insulation double-glazing, which provides abundant daylight (LT = 78% ), prevents heat loss (Ug = 1.0 W/(m²K)) and enables solar energy gains when the sun is low.

Above that, in the third segment of the stack, laminated safety glass with an ipasol Bright White LR with a custom coating forms the outer shell of a closed cavity facade (CCF). This particularly bright coating transmits abundant natural daylight (LT= 83%) and reduces reflection by around one third compared to ipasol Bright White with a standard coating. The inner part of the CCF is iplus 1.1 thermal insulation double-glazing, which is optimised for high daylight transmission. This combination was also used to glaze The Lookout, the uppermost block of the building and home to a public viewing gallery whose spectacular views of the London skyline are helped along by AGC’s Clearvision low-iron glass, which maximises colour neutrality.

All base glasses in the ipasol and iplus family are Cradle to Cradle Certified® Bronze and are also available in Low-Carbon versions from AGC’s new range of low-CO₂ products, all of which have a corresponding EPD. Architects and planners can use these low-carbon products to improve the classification of their buildings when applying for environmental certifications, such as DGNB, LEED and BREEAM.