CASE STUDY | MARSHALL BUILDING A passive giant The London School of Economics Marshall Building invites the public to the heart of the university via its spectacular Great Hall. Andy Pearson finds out how ChapmanBDSP used the concrete structure to deliver a passive-first design that delivered natural ventilation in key areas T he design adopts a fabric-first approach with passive design features to limit the demand on mechanical systems, says Tom Williams, associate at ChapmanBDSP. Hes talking about the Marshall Building, an 18,000m2 development for the London School of Economics (LSE), for which optimisation of form and fabric have been instrumental in minimising energy use. Designed by Grafton Architects, with ChapmanBDSP as MEP consultant, the Marshall Buildings imposing Portland-stone faade faces onto Lincolns Inn Fields. Its lower storeys are clad in ashlar blocks interspersed with large, punched window openings, and, above, two successive layers of angled fins form an orthogonal stone veil in front of the glazing. The side and rear elevations are more jumbled where they front the tight network of streets that make up the LSE estate. ChapmanBDSP used daylight modelling and irradiation mapping to develop the faade design, to ensure access to natural light and fresh air. Its permanent solar shading is dimensioned to reduce solar gain and minimise summer overheating. The ideal scenario in terms of reducing operational energy is to design the building to limit the amount of mechanical services we put into a space, introducing them only where they are needed to perform a specific function that cannot be achieved through passive means, Williams explains. The building houses lecture theatres, informal study spaces, academic offices, public spaces, music rehearsal and arts spaces, squash courts, and a sports hall. These facilities are stacked vertically the sports hall and squash courts in the basement, civic space on the ground floor, teaching spaces and lecture theatres on floors two and three, and research and departmental spaces on floors three to nine. The most spectacular of the spaces is the expansive entrance hall. Here, giant concrete, tree-like structural columns support the concrete mass of the building above. One of the columns even disappears through a void in the ceiling, and a broad, curving concrete stair sweeps students up through a second void to the teaching spaces. This Grand Hall is naturally ventilated. At one point, it was intended to be an open piazza outside the building envelope, but as the design developed it became incorporated into the occupied space, Williams says. High-level openings in the exposed faades that enclose three sides of the hall allow fresh air to enter the space. ChapmanBDSPs experience as engineers for the LSEs Centre Building, completed 32 April 2022 www.cibsejournal.com CIBSE Apr 22 pp32-34 Marshall Building Supp.indd 32 25/03/2022 17:36