Justin Snoxall, British Land Group
Building type, sector and stage
Non-domestic, new build, office, post construction, in-use, London
Office, BREEAM, curtain walling, mechanical ventilation, air conditioning
201 Bishopsgate is a high rise office block located close to Liverpool St Station in central London. The 14 storey building of 37,000m2 usable floor space is owned by British Land and the Blackstone Group and is occupied by organisations within the financial and law sectors. The building is a high spec office development constructed of steel and concrete with 70% of the façade covered by curtain wall glazing.
The building was designed and built to meet BREEAM ‘Excellent' and achieved a C rated EPC upon completion in July 2008. This study analyses how a highly glazed building achieved these design standards, and if it is achieving low energy consumption levels in-use.
A short case study by British Land Group is available on their website here (external link). A longer case study from the occupants perspective is available form the British Council for Offices here (external link). The case study is free and registration is required.
Initial findings suggest that energy use for the building is higher than expected. Cooling, ICT and small power are higher than Part L predictions and it is thought that this is partly due to ‘out of hours' consumption, which is not taken into consideration during building regulations energy modelling. The team are continuing to collect sub meter data and analyse the energy consumption using TM22. British Land is actively reacting to the findings of the study as well as the recommendations from their monitoring and targeting (M&T) contractor.
Heating and Cooling
A centralised system comprising of three large roof top air handling units and three centrifugal chillers provide chilled water and tempered fresh air to each separately tenanted space. The standard fit out is then for fan coil units to provide local heating and cooling to occupied spaces. The large AHUs all incorporate thermal wheels to recover heat from extracted air, additional heating to the fresh air entering the building is then provided by electric heater batteries within the AHU. A large open plan reception and atrium space with high ceilings is heated via electric underfloor heating.
Hot water is provided by point of use electric water heaters with some tenant hot water demands provided by a gas-fired water heater.
Lighting for the base building is a mixture of LED and fluorescent luminaires controlled and metered by Broadgate Estates. All office space lighting is the responsibility of the tenant who is free to install whichever lighting and controls that they desire. A standard tenant area fit out is for T5 fluorescent luminaires with daylight dimming for perimeter fixtures.
70% of the building façade is made up of glazing. A solar gain, glare and thermal bridging study has been carried out by the project team in order to determine the in-use performance of the glazed façade. The study also includes an assessment of the effectiveness of the internal blinds and how they are operated by tenants.
Key Performance Indicators
Project cost: £151 million (including neighbouring Broadgate Tower)
Floor area: 37,000m2
Building regs estimate of CO2: 32.5 kgCO2/m2.yr
BREEAM rating: Excellent
EPC rating: C (66)