Design of tall buildings with case study of 20 Fenchurch Street. Presented by Vince Ugarow, speaker of the Swegon Air Academy for CIBSE West Midlands in Birmingham.
Vince´s presentation was a clear example of successful and efficient collaboration between architects and engineers. The main players from design and construction must from beginning to end have strong collaboration in order to build an energy‑efficient and iconic building in a controlled development. Naturally this is easier to state than achieve.
Income meets the costs when a building has an optimal height and facilities are efficiently designed and used. Key elements are plant strategies, cores & risers, hydraulic systems, the requirements of tenants (present and future) and sustainability. All these elements were clearly described in a case study of 20 Fenchurch Street in London, designed by architect Rafael Vinoly. The building on 20 Fenchurch Street is set to become one of the major London landmarks. This 36 storey tower will be mainly offices with retail units at ground level. A sky garden with external space with natural ventilation at the top will offer spectacular panoramic views of the city and it will serve as a public space.
Vince gave a detailed explanation about the design and location of plant zones and cores at various levels depending on the height of the building. Double height sky lobbies are a way to gain space for equipment rooms maintaining standardised layouts above and below, to provide an acoustic/anti-vibration buffer zone and to contain the drainage from washrooms, among other facilities. With an eye on the future, good design practice is to specify goods lifts which can transfer heavy mechanical equipment in modules and, in the future, facilitate replacement of the building’s mechanical systems. Design and construction of the building can be done efficiently using prefabricated toilet facilities as a fast way to build on site, use of pre‑insulated duct works and jointing techniques to minimise riser requirements.
Vince showed a clear example of a sensible design that can meet the needs of different types of tenants. Tenant requirements anticipate changes, such as the ability to increase the outside air, the redistribution of the air and the ability to cope with additional kitchens and restaurants. In addition, there are other requirements such as 24-hour cooling, the ability to expand the washrooms for increased occupancy, electric diverse routing and spaces for UPS, secure routing for communications and space for satellite dishes, and many others.
A little surprise was caused by Vince´s energy hierarchy pyramid, which describes the return on investments. This pyramid scheme indicates that the largest investment return is in mass and built form of a building, such as orientation, shape and fabric. The facade is the second most influential element and the third are energy‑efficient systems. Using smart lighting of 8 W/m2 instead of 12 W/m2 can reduce the energy footprint but the larger saving can be achieved if you consider the (day) lighting from the beginning of the building process. Surprisingly, infrastructure, off-site and on-site renewables will bring the lowest return on investments.
The Fenchurch Street building has a total of 6 chillers in the basement (water cooled and absorption chillers) and separate air cooled chillers on the roof for common rooms. Based on the needs of tenants, there are fan coil units or chilled beams on each floor. There are also photovoltaic panels to generate roughly 27,000 kWh. In the future, the building can be connected to the district heating network. Tenants will receive handbooks on the obligations to achieve the BREEAM efficiency target of Excellent and an EPC rating of 40.
Over 40 engineers attended this seminar organized by CIBSE and Swegon Air Academy, and many people gave the feedback that Vince´s presentation was one of the most interesting seminars ever attended.
Image: 20 Fenchurch Street by Hilson&Moran