How the Palace of Westminster gets rid of all that hot air in the House of Commons

Ringing through the changes. Hernán Piñera, CC BY

Images of the crumbling fabric and antiquated network of environmental services, including the mechanical ventilation and air-conditioning system in the Palace of Westminster, suggest that the building may have had its day. Yet appearances may be deceptive.

A research project that I’ve been leading since 2012 has shown that the palace is actually a highly innovative building. The striking skyline of Gothic towers and turrets is the outcome of Victorian technical achievement and architectural design, and the stack system which provided ventilation for the debating chambers for more than 90 years is one that is now being widely considered as a model for low-energy, sustainable ventilation in large public buildings.

The initial design

Victorian engineers and scientists were confronted with the challenge of resolving the two parallel (and, at times, competing) agendas of a flamboyant Gothic scheme and the problem of ventilating such a large building in the days before mechanical ventilation and air conditioning.

Since Christopher Wren remodelled the interior of St Stephen’s chapel for the House of Commons in the 17th century, the issue of air quality and temperature in the debating chamber had been a major concern. Overcrowding and candle lighting made the space difficult to keep cool and adequately ventilated. A fire in 1834 gave the opportunity to rebuild the palace – and an architectural design by Charles Barry and Augustus Welby Pugin was selected in January 1836, four years before the government decided on a stack ventilation system.

Reconstruction of the ventilation in the temporary Houses of Commons, 1836-1851. Henrik Schoenefeldt, Author provided

It was a Scottish physician, David Boswell Reid, who presented a series of diagrams outlining what he considered the ideal ventilation system. Reid’s vision was a centralised system that would serve the entire palace, in which all of the fresh air was introduced through air shafts inside the Clock and Victoria towers. The air would be supplied to the different rooms via the basement with the aid of steam-powered fans.

The towers were part of Barry’s original architectural plans, but a third tower, known as the Central Tower, was added to function as a stack through which the building’s hot air could be exhausted. The stack effect was to be enhanced by waste heat from gas and smoke fumes, at times boosted with the aid of coke fires.

Modelling the system

Reid tested his design in a model debating chamber at his laboratory in Edinburgh and, from autumn 1836, was able test his system in two chambers built as temporary accommodation for parliament. Members were directly involved in evaluating and refining the system, which included a sophisticated climate control strategy that created individually controlled micro-climates in different parts of the chamber.

After four years of experimentation, Reid was finally employed to develop the stack ventilation system for the actual palace. But applying his system to the existing architectural design posed insurmountable difficulties and in 1846 the centralised scheme was abandoned. A simpler system using local turrets was adopted instead. Reid’s responsibility for the ventilation became confined to the House of Commons – while the architect, assisted by Michael Faraday and his engineers, took on the ventilation system for the House of Lords. Between 1847 and 1860 numerous local turrets were gradually introduced across the palace to serve individual sections.

The Central Tower was reduced in size and the striking skyline of turrets that contribute to the palace’s distinctive Gothic character, evolved in response to this decentralised approach. The original drawings and sketches also illustrate that the tiered outline of the turrets fulfilled functional requirements and that the stacks had sophisticated mechanical details such as storm guards and wind-sensitive louvres. Pugin and Barry subsequently gave the exterior of these utilitarian structures the appearance of elegant Gothic spires.

Monitoring and control

The general principle behind the system was simple but its day-to-day operation involved a complex process: continuous monitoring of weather conditions, indoor climate and occupation levels and user experience. This was done entirely manually in a strict operational regime.

To maintain comfortable conditions the system had to respond to changes in the weather and fluctuations in the number of MPs, but also to highly subjective factors, such as the perception of temperature, humidity or air currents that members encountered inside the debating chamber. The monitoring system involved collecting and processing user feedback, alongside measurements. During every sitting the speaker or the sergeant-at-arms reviewed feedback from MPs, passed to them by messengers and, if necessary, gave orders to make ad-hoc adjustments to the climate conditions or the ventilation rate.

Although the speaker and many members knew that it would be impossible to achieve a full consensus on comfort, dissatisfied MPs frequently put pressure on attendants and engineers by demanding adjustments. In 1852, and again in 1854, the MPs appointed a select committee to review the design and management of the ventilation.

Reid’s original system was replaced with a new system after merely two years due to sustained pressure. He was never given enough time to fully complete his system, let alone demonstrate its full capabilities.

A new system by the physician Goldsworthy Gurney was adopted and in the House of Commons revealed significant improvements in temperature and air quality, but more importantly it received approval from MPs and a similar system was adopted in the House of Lords.

No fewer than ten select committees were appointed over a 90-year period to specifically coordinate continuing scientific evaluations and performance.

The end of a legacy

The House of Commons was completely destroyed by the German Luftwaffe in 1941. The last, most systematic and comprehensive scientific evaluation before this historic system was destroyed was undertaken between 1902 and 1931. This included chemical and pathological examinations of the air, physiological studies, and investigations into improving air flow.

In 1944, a special select committee recommended a modern system with air conditioning to replace the original Victorian system, which it dismissed as “antiquated” and “ineffective”. The new system was instead described as the “best which modern science can devise”. On several occasions between 1941 and 1943 Winston Churchill spoke passionately that the “traditional character” of the original debating chamber should be restored, yet advocated embracing modern technical solutions for the ventilation.

Over the past seven decades we have experienced yet another change of attitude, and the forthcoming refurbishment opens up the opportunity to revisit the potential of the historic system. Stack ventilation is now touted for creating sustainable systems in large public buildings. There are numerous modern examples, including UCL’s Schools of Eastern European and Slavonic Studies or Cambridge’s Department of Mathematical Sciences.

Back in fashion: Cambridge’s maths department sports stylish stacks. Dmitry Tonkonog/Wikimedia Commons, CC BY

Commons speaker John Bercow recently said that refurbishment required an approach through which the “Victorian legacy can be rendered practical for contemporary representation”. Detailed studies of the performance of the historic system that I’ve carried out suggests that that past could potentially inform the current renovation in a sustainable manner.

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