Westminster’s sewers for air and smoke

A few months ago I have reported in my blog about the early stages in a survey of the historic ventilation voids inside the Houses of Parliament that I have been coordinating. Over the last four months the focus of the survey was on retracing the ventilation arrangements at roof level and how they were linked to the ventilation turrets. In addition to the roof space itself, which contained many channels for smoke and vitiated air, a separate mezzanine floor with vaulted ceilings and floors was inserted below the roof level. Well disguised behind large spandrel panels, parapets and false windows, this mezzanine level is not noticeable externally. This ‘hidden floor’ was used to collect hot air and smoke from every room in the Palace and to convey it to ventilation turrets to be discharged. The interior of these largely windowless spaces has a close resemblance to the pillared hall of Finsbury Park’s sewer reservoir. It contains an extensive network of interconnected chambers that function like a sewer systems of large cities, such as London, New York or Vienna, but instead of sewage it was used to collect and carry off smoke and vitiated air.

The origins
These spaces were original introduced as a part of an earlier scheme developed by the medical doctor David Boswell Reid. His plan was to collected the smoke and vitiated air from the entire Palace at roof level and discharge it centrally via the tall tower above Central Lobby. He introduced two networks of horizontal channels, one for smoke another for vitiated air, that were to be connected to the Central Tower. It is to be noted that the Palace had several hundred fireplaces, that would produced severe problem with smoke pollution around the Palace. Charles Barry’s original plans, which were produced before Reid was employed to develop ventilation system, had followed a more conventional approach. It involve the use of individual chimneys for each fireplace. This, however, was reject by Reid as unfeasible due to the level of pollution at low level and instead propose to eject it centrally and at a high altitude. The original plans and sketches produced by Reid and Barry show an enormous network that linked the smoke or air flue of every room to the Central Tower. The channels covered long distances, with the main channels measuring between 150 to 200 meters.

Although Reid’s idea of discharging the smoke and air centrally through one tower was abandoned after six years of planning, the infrastructure established by Reid was not discarded. The onsite surveys have revealed this network was completed as outlined in Reid’s plans and it was re-used by Barry. Instead of being connected to the Central Tower, however, it was sub-divided into multiple local systems, each provided with a separate ventilation turret. These were added to the roof of the Palace between 1846 and 1854. This included the turrets on the River Front. Two of these shafts were added by Barry in 1847 to provide an outlet for the smoke and air channels of the River Front and Speaker’s Residence. In each of these turrets the smoke channels were connected to an iron-flue running through the centre of the air shaft. The air rose up through the space around the smoke flue. This allowed to utilise the waste heat of the smoke to enhance the convection of the vitiated air without mixing smoke and air. The surfaces of the smoke shafts, composed of highly conductive galvanised iron, warmed the vitiated air passing through the space around it. As the smoke had to travel over longer distances to reach the shafts, it was necessary to boost the convection within the smoke shaft artificially, using steam coils. The smoke channels leading to the turrets are large spaces. They can be entered through cast-iron access doors and their ceilings are generally high enough for a person to walks through them with the head down. The interior of these spaces are covered in dust, mostly composed of lime and fine sand from crumbling mortar and plaster, and the former smoke channels are covered in thick layers of black soot. Their interiors are still pitch black, and even if they are lit with electric torches, they remain dark. They were filled with distinctive tar-like smell of soot.

Reclaiming the forgotten Voids in the context of the Restoration and Renewal Programme.

Having provided important new insights into the historic fabric, the findings of this research will be used by the external team architects, to explore ways in which these voids, most of which are currently unused, could be utilised in the context of the forthcoming restoration. Not an insubstantial proportion of these spaces are large enough to be used for offices. Design investigations will be undertaken to determine how these disused spaces could be exploited. One of the options to be explored is reinstating a stack-driven system that utilises the historic infrastructure. This will follow principles similar to those deployed in modern advanced naturally ventilated buildings. In modern building the cost of the large spaces requires for advanced naturally ventilation represent a major obstacle to its wider dissemination, but in the Palace these spaces are already provided.

Another scenario would be adopt the roof mezzanine as a ‘environmental service floor,’ not dissimilar to those found in modern office towers. This would allow to use the space for the accommodation of modern environmental services in way that they can easily by engineers for maintenance purposes. Currently much of the environmental services, such as the electric cabling, heating pipes or ventilation ducts, are fitted very tightly in narrow spaces, making it difficult to access them for maintenance or renewal. One of the requirements of the design is to introduce a service infrastructure that can be maintained and even completely replaced with new services in the future without requiring Parliament to vacate the building again. The system thereby would follow the maintenance strategy of a desktop computer. A computer is a case with modular electronic component, which can be removed and upgraded with new hardware without replacing the entire machine. In the Place the historic voids would perform the role of a container of interchangeable services.


A computer case with easily uupgradable components. The design of the new building services in the Palace of Westminster are to follow a similar maintainance strategy.

The architects in charge of the refurbishment are to be appointed later this year pending on vote in the House of Commons and Lords. Over the past four months I have new writing a detailed and illustrated report to provide the architect with an overview of the historic arrangements and how they were originally operated. I will also convene workshops and give onsite tours to introduce the architect to the large and complex network of ventilation voids. This will be followed by various workshop-based design studies to explore the potential strategies re-using of the historic infrastructure. In the meantime, however, I will focus on a very detailed study of the design and performance of the historic system in the House of Lords.


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