Southmead’s super hospital

Hospitals don’t come any bigger or more cutting edge than the Brunel building in Bristol, which combines the latest medical facilities with a high spec design developed to boost patient well-being as well as environmental performance. Stephen Cousins reports

In the ever advancing field of public healthcare, technological innovation is increasingly being matched by efforts to improve patient “healing” and well-being by designing hospital environments with greater access to natural daylight and ventilation, more generous spaces and a less institutional feel.

The UK’s boldest example of this evidence-based approach to design is the £430 million Brunel building at Southmead Hospital, in Bristol, a new breed of “super hospital” featuring light-filled internal courtyards, naturally ventilated patient rooms, and a huge full-height glass atrium as tall as the nave of Westminster Cathedral.

The 1.2 million sq ft building is one of the most advanced acute care facilities in Europe, which includes three extensively glazed U-shaped ward blocks, designed by multidisciplinary architect Building Design Partnership (BDP) to maximise light and views across the adjacent landscaped grounds. In addition, a high quality palette of internal and external finishes was specified to overturn the traditional austerity associated with NHS hospitals and make patients feel like they are in a hotel or a private hospital.

“The client, North Bristol NHS Trust, wanted a very high specification civic facility to replace its existing estate, which was spread very piecemeal over two sites (Frenchay and Southmead) and made up of inadequate wartime era single storey buildings with awful environments for patients,” said Christopher Green, project architect at BDP. “We wanted a step change from that and create the highest quality building we could.”

The Brunel building will serve a local population of half a million and was built by Carillion under a PFI contract for North Bristol NHS Trust, the largest ever UK construction contract taken on by the main contractor. BDP was employed by Carillion as lead designer, TPS as structural engineer and DSSR as M&E services engineer.

North Bristol NHS Trust’s brief for the project was unconventional and informed by research showing that good design can have a positive impact on patient well-being and recuperation rates and the job satisfaction of staff. The Trust set out strict design criteria that required the hospital to be flexible enough to adapt to changes in the way healthcare is provided; to maximise access to views and light through efficient use of glazing and layout; and include excellent internal and external finishes not normally associated with a state-funded hospital.

The Brunel building stands on a 27-hectare brownfield site within the existing Southmead Hospital grounds, located 2km outside the city centre, and contains 800 acute beds and 24 theatre suites. Everything from Frenchay has been transferred to the Brunel building, from its world class burns unit, to its neurological department.

A total 75 per cent of patients will be housed in single en suite rooms – the highest proportion of any major UK – with 25 per cent in small four-bed single-sex wards. And in another first, the building was designed to be the most sustainable major acute hospital in the UK, achieving a BREEAM Excellent rating and a carbon footprint below government targets.

Although high reaching, the building’s environmental strategy is relatively simple and, in line with the client’s patient well-being demands, based on the idea of maximising levels daylight and natural ventilation.

Hospitals are not normally ideal candidates for natural ventilation, reliant as they are on heavy services that require mechanical ventilation, and subject to strict regulations around acoustics, pollution and safety normally restrict the use of openable windows.

“, we came up with the idea of creating a distinct split between the ward blocks, which are focused on patient recuperation, natural ventilation and views from bedrooms of landscaped areas outside, from the high tech, mechanically-cooled and ventilated treatment areas in the clinical block. The central atrium is created in the space between the two,” said Green.

By dividing off the clinical areas from the wards and naturally ventilating half the building it was possible to cut the amount of energy needed to run it by about 50 per cent, per 100 cu m, compared with the existing hospital. Energy use was also reduced through the use of a biomass boiler, which provides 20 per cent of the power demand.

The patient wards are arranged within three U-shaped, steel framed blocks to the west, each with its own internal landscaped courtyard and generous external glazed facades providing views of the landscaped grounds from patient rooms. The wings are shallow in plan with single-occupancy rooms arranged along a central corridor, which helped maximise the effect of natural ventilation and also allow for cross-ventilation.

The clinical block is supported by a post-tensioned, reinforced concrete frame and houses the heavily-serviced diagnostic and treatment areas, including 24 operating theatres, critical care units, MRI and X-ray rooms, all of which are mechanically ventilated with heat recovery systems.

These two blocks are positioned either side of a soaring, 280m-long full-height atrium, which functions as the hospital’s circulatory spine and rises in stages from four storeys at the southern end to a seven storey-high main entrance to the north.

The atrium was heavily inspired by Norway’s innovative Oslo University Hospital, and resembles an urban street, divided in plan by several glazed corridors spanning between the ward and clinical block to create three main spaces. Each space has its own public stair and lift core, to transport visitors and relatives from the ground floor to the wards, and features different coloured facade panels – green, blue and red – and different materials as part of the wayfinding strategy and to further emulate the character of a real street.

“We considered designing a low level roof over the concourse, but it would have not given the same quality of internal light and we wanted this space to be the heart of the building,” said Green. “Having a large internal space allowed us to use much brighter and delicate internal finishes on the walls, rather than rough external finishes, as we didn’t have to worry about weathering.”

The atrium also forms part of the natural ventilation strategy, its large volume encouraging air to circulate. And the faceted glass roof permits large amounts of natural daylight to penetrate into the street below, the wards and clinical block. An estimated 80 per cent of the operating theatres in the clinical block are naturally lit.

The atrium roof is divided into three huge, flat wing-shaped elements, each of which has a “wind catcher” positioned at its centre, designed to ventilate the space and extract smoke in case of fire. Each one is about three times the length of a double decker bus and twice the height.

One consequence of the different structural solutions used for the ward block (steel) and clinical block (concrete) was a high degree of movement in the atrium roof, which spans between them. As a result, the structural steelwork supporting the atrium roof is designed to accommodate +/-40mm of movement across the entire length of the building. The roof and the walls are fixed to separate steel structures that allow the roof steelwork to slide over the tops of the walls.

“Although the roof’s design isn’t that complicated, the interfaces with the rest of the building are,” says Green. “One of our architects in charge of the roof packages spent a great deal of time modelling the components in 3D, which we don’t normally have to do when there is a specialist contractor involved. We wanted to make sure everyone was clear on what they were doing.”

The sheer scale of the hospital means there are around 50 separate roofs in total. Several green and brown flat roofs are installed on the lower levels of the ward block, which have been landscaped to include intensive shrubs, trees and gravels. The roofs on the clinical block include specialised paving designs, including ramps and other features intended for use by patients as part of their treatment.

Although the Brunel building was designed and built during a recession, there was very little value engineering involved to reduce costs. According to Carillion’s project manager Keith Hutton, who has built two major PFI hospitals before, it is a one-off in terms of the quality of design detailing and the specification of materials.

“There was strong attention paid to the specification of joinery and other features throughout, which we considered this the right thing to do to reduce maintenance requirements and create longer term value for money.”

Alongside the building’s state-of-the art clinical facilities, and other measures designed to improve patient well-being, they help set Southmead Hospital apart as one of Europe’s leading centres of healthcare.