Steven Pidwill on Associated Architects’ Centre for Medicine at Leicester University – the UK’s largest Passivhaus building

Buildings.

Words
Steven Pidwill

Photos
Martine Hamilton Knight

Though founded in 1921 as a memorial following the first world war, the University of Leicester was granted a Royal Charter to award its own degrees only in 1957, after which much of its architecturally rich campus was developed. Today it is among the UK’s highest-ranking institutions for both teaching and research and a cornerstone of a city that has recently taken much pride in burying both the remain of Richard III and footballing reputations.

The main campus, on a steeply sloping site to the south of the city centre, is an intriguing mix of new and old, with a significant architectural influence from five Royal Gold Medallists. Edwin Lutyens designed the Arch of Remembrance in the adjoining Victoria Park and its processional route from University Road. Leslie Martin prepared the 1956 development plan (and completed a group of faculty buildings), and set the scene for the other three: James Stirling (whose celebrated Engineering Building was designed with James Gowan), Denys Lasdun (Charles Wilson Building) and Philip Dowson of Arup Associates (Attenborough Tower).

In recent years, my colleagues at Shepheard Epstein Hunter and I have been responsible for the university’s development plans and delivery of a number of projects, including the Percy Gee student union building.

Associated Architects’ £42m Centre for Medicine (CfM) sits on the north side of the campus on land previously owned by the adjacent sixth-form college. It is close to the De Montfort Hall, famous for hosting Bowie and the Beatles, and across the road from the Medical Sciences block, a 1970s gas-guzzling deep-plan building with which it begs comparison: the CfM’s energy use should be less than one-fifth that of its neighbour.

The new Centre for Medicine is four times the size of the largest existing Passivhaus-certified building in the UK.”

In February the CfM was accredited as the UK’s largest Passivhaus building, successfully meeting the low-energy standard developed in the 1990s by Wolfgang Feist and Bo Adomson. In terms of the CfM’s building fabric, this means all windows are triple-glazed, U-values to roof and walls are very low, ventilation is mechanical with a high level of heat recovery, and – most critically – heat loss through air exchange with the outside is efficiently controlled by massively reducing accidental leakage. This requires an obsessive approach to sealing around windows and other openings and the avoidance of cold bridging, both in the detailing and the execution. In addition, air is ‘naturally’ pre-warmed or cooled (depending on the season) by passing through a 1600-metre-long underground labyrinth of large-bore intake pipes.

But what does this rigourous approach mean for the architecture? Is the designer constrained by virtue? The answer here seems to be “no”: the CfM is as much a response to context and an urban design strategy as it is to low-energy design.

Buildings.

Occupying a prominent, previously greenfield corner site, the building needed to speak well for the university and have civic presence without baiting the conservation officer or dwarfing the sixth-form college to the west. Its internal organisation can be easily read from outside: three narrow blocks of three, six and seven storeys run parallel to University Road and appear to sit on a deep-plan podium, which is clothed on the two public sides in a double-height white stoa, with piers at close intervals, some of which are structural, while others contain ventilation ducts. The effect, from the street, is strong and simple. On the west elevation is a green living wall (Iooking healthy so far), with vertical planting tidily framed by fenestration.

Associated Architects’ brief required relatively few types of space: two lecture theatres to accommodate around 300 and 200 respectively, 30 seminar rooms with between 20 and 40 seats, and 125 single-person academic offices, standardised to avoid the perception of hierarchy and to allow future flexibility. Of the laboratories, some are single-person testing cubicles, some are more specialist and are isolated by Faraday cages that shield virtual reality experiments from electromagnetic interference. There is also a cafe, support staff offices, shared social spaces and meeting rooms.

Buildings.

In contrast to earlier models of sustainable architecture relying on openable windows, chimneys and cross-ventilation (exemplified by Short & Associates’ 1993 Queen’s Building at nearby De Montfort University), there are a series of plant rooms which together take up significant floor area. The largest, at 750 square metres and a height of 5.5 metres, is in the basement and serves the most heavily occupied spaces on the ground and first floors and the top floor of the three-storey block. Another plant room is dedicated to the larger lecture theatre, and two more, each 200 square metres, on the roofs of the taller blocks serve their respective upper floors.

Buildings.

Internally, on my visit, there was a pervading sense of calm and good levels of daylight. It’s a shame that the entrance lobby takes the form of two huge airlocks, which means that you approach the main axis from the side, but the solution can be excused by the fact that a potential major source of heat loss had to be addressed.

In most of the large rooms the slab soffits, which incorporate cast-in cooling pipes, are exposed, and (to my surprise) occupants can open many of the windows (or louvred panels) without upsetting the whole strategy. Solar shading is by automatic external blinds, and rainwater pipes are also external – not always ideal for a civic facade – because of the cold-bridging implications of running them inside.

Achieving the Passivhaus standard is no small feat for a large teaching and laboratory building, but it is not the only notable thing about the project. The Centre for Medicine comes across as a very practical building, with clear organising principles, that is likely to age well. It provides an excellent model for making large-scalelow-energy architecture of quality which works well for users and provides necessary flexibility for the future.

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Credits

Architect
Associated Architects
Project manager
Bidwells
Cost consultant
Gleeds
Passivhaus certifier
Warm

Curtain wall
Advanced Glass Facades
Green wall
ANS
Composite cladding
Skygreen, Kingspan Benchmark
Glass balustrades, solar shading
Scala Vetro