Innovative designs for retrofitting the vast NHS estate to stem rising carbon emissions and adapt hospitals to perform through a changing climate are being created through a multi-university collaborative effort.

Our adaptation schemes are based on passively driven natural ventilation and cooling, operating in well-insulated buildings

Alan Short

“The scale of the problem is huge. We have until 2050 by the obligations under the Climate Change Act to get our emissions down by 80% from what they are now, and we don’t know how to do that.”

These words, spoken by Paul Morrell, former UK Chief Construction Advisor, spell out the challenge the NHS faces in attempting to reduce the 18 million tonnes of CO2 it is responsible for producing every year – around 3% of the entire annual UK emissions – by its 28 million m2 of buildings.

It’s a challenge that has taken on a new urgency. As summers are predicted to warm, hospitals are under pressure to reduce the risk of overheating, particularly in the sort of heat waves the UK experienced in 2003, 2006 and 2009, because of the associated increased mortality rates.

“Faced with more frequent hot spells, NHS acute hospital trusts may turn increasingly to air conditioning,” said Professor Alan Short from the University of Cambridge's Department of Architecture. “But such energy-intensive strategies would have a disastrous effect on the national carbon reduction programme. It’s a double whammy: the pressure to reduce energy consumption colliding with the pressure to protect patients and staff from overheating.

“The last government’s plan was to replace the NHS Estate with a suite of new hospitals but the 2008 economic collapse put an end to that. And that means turning back to the existing estate. How can we make the best use of the stock we’ve got to make it fit for purpose?”

The answer, Short believes, is to be found in the innovative low-energy design strategies that have been developed as part of the recently completed Design and Delivery of Robust Hospital Environments in a Changing Climate (DeDeRHECC) project that he has been leading. The collaborative team included researchers from the Universities of Cambridge, Leeds and Loughborough and the Open University, and was funded by the Engineering and Physical Sciences Research Council with support from the Department of Health.

“Our adaptation schemes are based on passively driven natural ventilation and cooling, operating in well-insulated buildings. They provide greater resilience to increasing temperature, mitigate carbon emissions and can be provided at a cost that is completely in line with NHS refurbishment costs.”

To begin, researchers at Loughborough fitted sensors to carefully selected types of NHS buildings to monitor the inside temperature over the course of two years, creating what they believe is the largest database of environmental data on non-domestic building stock collected in the UK since the 1980s. These data, together with UK Climate Impacts Programme predictive databases, were used to calibrate computer simulation models to predict internal temperatures in 2030, 2050 and 2080 for various adaptation options in the case study hospitals.

Although the NHS estate is vast, it comprises a small number of recurring building types, as researcher Dr Alistair Fair in the Department of Architecture described: “You can see the same types of buildings occurring again and again and NHS Partner Trusts were chosen to yield a good cross section.”

The project’s four participating NHS Trusts were Cambridge University Hospitals NHS Foundation Trust (Addenbrooke’s Hospital), Bradford Teaching Hospitals NHS Foundation Trust, West Hertfordshire Hospitals NHS Trust and University Hospitals of Leicester NHS Trust. For each, representative categories of space were examined – non-clinical, patient rooms, diagnostic, treatment and open wards.

Addenbrooke’s Hospital has a medium-rise ward tower of a type one can see in at least 50 other NHS sites. The study shows that this tower is barely resilient to current hot conditions, and then only as a result of uncontrolled air leakage. “In winter, it is an epic NHS gas-guzzler,” said Short.

“Even with relatively modest adaptations, much can be achieved, and a combination of sunshades for the windows, naturally driven cross-ventilation and stack-driven exhaust systems to flush the heated air would alleviate temperatures without increasing the fuel bill,” he added.

The stack technology required to determine airflow routes to single spaces was devised with the help of the Pathogen Control Engineering Institute at Leeds, and is effective in reducing airborne cross-infection risk within the hospital – an essential prerequisite of any adaptation scheme.

One of the most resilient hospitals to increasing temperature is one of the oldest. Bradford Royal Infirmary was built around the Nightingale ward: long thin wards arranged with beds facing each other to Florence Nightingale’s very specific dimensions. “The potential resilience is a result of the heavy-built brick fabric of the building and high ceilings, which need to be coupled to intelligently controlled ventilation. Our analysis shows the revival of Nightingale’s cross-ventilation scheme is enough to maintain this resilience through to 2080,” said Short.

Now the team is converting research findings such as these into ‘off the shelf’ construction designs that can help Trusts and policy makers decide whether to decommission buildings, invest in relatively minor interventions or contemplate more substantial interventions for longer term resilience.

“All of our case studies show that we need environmentally responsive design. It is a mistake to rely on gluing renewable technologies to ‘business as usual’ buildings. These adaptive ideas yield easy wins – grounds both for optimism and action.”

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