110 Bishopsgate is a skyscraper located in the City of London financial district, referred to as “Salesforce Tower,” formerly “Heron Tower,” famous amongst Londoners and tourists for the internationally celebrated cocktail and restaurant experience at Duck and Waffle on the 40th floor and the cultural fusion of SUSHISAMBA on the 38th and 39th floors, offering unparalleled 360 degree views across the city. The building was completed in 2011 by British property developer, Heron International, standing at a statuesque 230 metres tall. 

London’s Historic and Modern Architecture

Bishopsgate is a major thoroughfare in the city and formerly one of the eastern gates in London’s historic defensive wall; named after Earconwald, a 7th Century Bishop. The road is a spectacular exemplar and public display of London’s duality of notable Roman infrastructure, intertwined with striking modern architecture, creating a world-famous skyline. Heron International aspired for 110 Bishopsgate to be distinct amongst its competitors as a market-leading building for commercial tenants, underpinned by an enlightened vision of making the development as high–performing and efficient as possible. 

In 2020, Heron International sought advice from HDR’s engineering services, in a concentrated effort to enhance building efficiency. Subsequently, HDR was brought on board to provide a holistic building engineering services solution, encompassing mechanical, electrical, and public health design (MEP), sustainability and resiliency, in addition to lighting design.

Despite reduced building occupancy in recent years due to restrictions following the COVID–19 Pandemic, utility bills at 110 Bishopsgate were not decreasing and energy usage was high. As an aside, the then British Government had published proposed plans for future reforms, involving requirements for energy performance certificates (EPCs). This means a commercial property cannot be let unless achieving at least an EPC C rating by 2025 and then in 2030, this requirement will be changing to a minimum of an EPC B rating. 110 Bishopsgate had already been registered with a C rating, and as such, HDR created a pathway to achieve a B rating ahead of 2030, outlining how this target would be reached in a given timeframe. 

HDR’s engineers surveyed the building, conducting a stage 3 report, reviewing critical systems and building management systems (BMS), determining obsolescence issues within the existing infrastructure and outlining recommendations on upgrades moving forward. The objective of this exercise was to determine a baseline of how the building was currently performing. The desired outcome was to define a strategic plan for the building, working towards achieving its full efficiency potential. These interventions led to Heron International requesting HDR to conduct a full energy remodel of 110 Bishopsgate.

A Full Digital Twin

HDR embraced a digital approach, placing modeling at the heart of its building engineering services operations, utilising a full digital twin to assist cost analysis, energy efficiency and enabling the landlord to bill their tenants accurately. 110 Bishopsgate was one of the first high-rise towers to adopt digital twin model engineering, and HDR was able to assess the impact of various upgrade options by using this approach. Through analysing data extracted from a 12-month period, engineers were able to focus on floors that were not performing efficiently and could subsequently address discrepancies. HDR also undertook surveys of existing building equipment and energy assessments to identify priority schedule of improvement works.

BMS upgrades were split into three separate parts. Obsolete controllers on critical systems, alongside metres that were not effectively communicating with the main building computer were identified as primary efficiency inconsistencies. These controllers were replaced, resulting in the systems on the floor running more efficiently. The chiller sequency project revealed the cooling system was wasting significant energy; thus, HDR developed an automatic system with a revised sequencing strategy. The final upgrade involved the replacement of all other obsolete BMS controllers and upgrade to the BMS head end, therefore, creating a coherent, holistic and flexible solution. 

“Comprehensive and considered refurbishment is going to play an ever-increasing role in the commercial office market, here in the U.K, Europe and indeed globally. In keeping with the client’s ambitious adaptive reuse ethos, many of the challenges centred on obsolescence issues and required strategies to be prepared for the complex replacement of plant whilst maintaining a fully tenanted and operational building. I am personally delighted that we have made this significant contribution to such an iconic landmark building.” — Mark Parson, Mechanical Project Lead, HDR

Nurturing Environmental Responsibility and Cost Efficiency

To harness building efficiency, the metering systems were updated. With so many critical information technology (IT) loads and high utility usage throughout the various floors, the upgraded metering system was designed to encourage a change in behavior amongst occupants, in a collaborative effort to lower costs. HDR also undertook investigations to determine improvements that could be made to the efficiency of the office ventilation system from each air handling unit, by implementing additional shut-off dampers and occupancy control of the plant through the use of CO2 monitoring.

Recommendations have been developed which have contributed to achieving a BREEAM In–Use Excellent rating and ISO14001 certification, through conducting social risk and opportunities, climate transition and natural hazard risk assessments; alongside curating detailed and intricate emergency plans. This included HDR collaborating with a public address and voice alarm systems (PAVA) specialist to replace the existing technology.

The data-driven approach adopted by our engineers for this project demonstrated that the lighting design strategy was also imperative to satisfying the sustainability and building efficiency ambitions of the landlord. The lighting design upgrade included replacement of existing fittings with efficient light–emitting diode (LED) equivalent substitutes across a multitude of floors, including stairwell lighting that would only function during occupancy. Through implementing this new strategy, HDR has been able to provide approximately 25% to 30% electrical energy savings at 110 Bishopsgate. 

Final practical completion of the first package of works is due in 2025. HDR’s sustainability and resilience team will continue to revisit the site in the future to extract metering data, testing it against various hypothetical yet possible scenarios, including the potential for the building to be integrated into a district heating network. HDR’s sustainability implementation plan will be utilised to define the path to net zero, with energy-saving benefits already demonstrable.

“The project work at 110 Bishopsgate has illustrated the merits of harnessing a holistic data-driven approach to building engineering services in enabling optimal performance and efficiency, not only addressing 21st century regulations and legislation, yet also defining tangible insights and learning outcomes, assisting the engineering of statuesque and elegant additions, as we continue to help shape the built environment.” — Gareth Rodwell, Project Director, HDR