Project Basics

Portcullis House is located on the corner of Bridge Street and , just across the street from (Address: Bridge St, , SW1A 2LW). The building type is divided between office and assembly as it is occupied by 210 members of Parliament and their 400 staff. This government building reaches to 6 stories and comprises of a total of 23,000 square meters or 215,000 square feet (About 36,000 s.f. per story). Design was accomplished by architects at Michael Hopkins & Partners and engineers working at Arup, and construction was completed on 18 August 2000. Background & Context

The design team’s primary goals were to The economics of the project caused much design an ultra-low energy building whose controversy. In fact, it is often seen as a systems were integrated with the structure, pretentious waste of taxpayers’ money. and to design a building that would fit into Perhaps that has something to do with the the site’s context, which includes important imported fig trees in the courtyard that landmarks such as New Scotland Yard, Big cost a bundle, or the less-than-satisfactory Ben, and the . energy performance of the systems. The construction of Portcullis House What has yet to be seen is the long-term was complicated by the reconstruction payoffs of the building’s cost. It could very of which is well be a wise investment. located directly under this site. In order to complete the project in a timely manner with the setback caused by the underground construction, the designers chose to rely on prefabrication. This choice was also ideal because of the minimal space on the site, and budget was obviously not an issue. The project cost £235 million, qhich was well above the initial budget of £165 million. About £4 million of the inflation is due to client variations, and £10 million were added through the late completion of projects underneath. The Design

In mass, the Portcullis House is a six-story square doughnut with a central courtyard/ atrium and vertical circulation in each corner. On the ground floor are shops and the entrance to the underground station on the street side, while the building’s main entrance is on the river side. Also on the ground floor is access for the underground tunnel to the Palace across the street. The upper floors are populated with offices around the perimeter, off a corridor that looks over the courtyard/atrium (see images). As mentioned before, much of the building was prefabricated including the slabs, floors, granite columns, fenestration, services risers, and the entire roof (including the plant rooms and services distribution). The facade was specially designed to be blast-proof, and the building as a whole was designed to last 120-200 years. Key Design Strategies

Low energy heating and cooling is Because of the lack of underground space, accomplished with 13 natural ventilation the mechanical systems had to be sized to towers. Fresh air is brought in through fit on the rootfop. The fourteenth chimney vents under the windows. The hot air rises is actually a flue for the mechanical to the top and is then directed either to systems, which were designed like those be cooled or directly to the offices. In the on a submarine in order for everything to winter, this air is heated by solar radiation function in such a confined space. while during summer months, the air is Some groundwater is stored onsite in a cooled by extracted groundwater from two greywater tank for toilet flushing, but excess boreholes sunk into a chalk aquifer. Water is discharged to the sewer. is extracted and stored in buffer tanks. The Portcullis design team chose wavy Whatever the time of year, the conditioned precast concrete ceilings to increase the air is pumped down the sides of the building’s thermal capacity, and high building into the floor void of each office, admittance surfaces to allow cooling using as shown in the diagram to the right. Each that thermal mass. vent can be manually controlled by that The building skin is designed to let adequate office’s occupant(s). light in thru the central atrium and windows The high-tech cladding is integrated with with light shelves in each of the offices. the mechanical ventilation system by way of Electrical lighting is mostly limited to a ventilated cavity behind the outer glazing. compact fluorescents on a Delmatic auto- dim system that responds to the daylight. Validation

The energy use goal was 90kWh/m/y Asking one author passionate about (for the offices), and target CO2 emission low-carbon design (http://inpicenum. was 750 tonnes/year. According to the com/2007/06/12/portcullis-house- Parliament: “All electricity consumed on emissions-pass-or-fail/) reveals these the has come from results: renewable sources since 1 February 2007, “Ignoring the figures for 2006-7 because of therefore there will be no carbon emissions uncertainty about the source of electricity, resulting from electricity consumption let’s look at 2005-6. For that year, in future. This has contributed to the Portcullis House used 7,230,601kWh of reduction in carbon emissions for the year energy and emitted 630.2 tonnes of carbon. 2006-07.” They don’t specify a breakdown for fossil fuels and electricity. Doing a bit of math, the figures look like this: To get to the figures in the chart: “First, convert the carbon to CO2 (multiply by 44 and divide by 12) to get 2310.7 tonnes. So now we know how many kWh they used in total and what their total CO2 emissions were. Using carbon intensities for mains gas (0.19kgCO2/kWh) and So the building uses 50% more electricity mains electricity (0.422kgCO2/ Portcullis House is said to use one-third and 60% more gas than a crappy 1990’s air kWh) and a little excel magic, we less energy and emit about 2,600 fewer conditioned office block. But this isn’t a get a solution for annual electricity and gas consumption. The total tonnes of CO2 than a conventionally air- standard air-conditioned building! floor area you get by working conditioned building, but is that good This is state of the art Green and it’s backwards from the figures in the enough? gone wrong somehow.” P.A. (7,230,601kWh divided by 332 kWh/m2 gets 20,712m2).” Subjective Performance Studies

Portcullis House has attracted a few awards, including the 2001 Timber Industry Award for the use of timbers in the atrium and the coveted in 2002.

When put to SBSE’s Regeneration-Based Checklist, Portcullis scores a final +75. This is based on a -750 for polluting some air and water, dumping untreated waste, being built mostly of virgin materials, and importing energy; and a +825 for recyclability (once its 120-yr-life ends), use of daylight, use of passive heating and cooling, ability to create pure indoor air, neighborliness, and beauty (in context). How To Get There Not open to the public. To visit, check the website for London’s Open House Saturday tours: http://www.openhouse.org.uk/ public/talkstours/architecturetours.html Resources http://www.galinsky.com/buildings/portcullishouse/index.htm http://news.bbc.co.uk/2/hi/uk_news/politics/1023847.stm http://www.caa.uidaho.edu/arch504ukgreenarch/CaseStudies/PortcullisHouse.pdf http://www.e-architect.co.uk/london/portcullis_house.htm http://www.arup.com/facadeengineering/project.cfm?pageid=1790 http://www.bsdlive.co.uk/story.asp?storyType=45§ioncode=93&storyCode=1155 http://inpicenum.com/2007/06/12/portcullis-house-emissions-pass-or-fail/ http://architecturelink.gemini.titaninternet.co.uk/NOF/bldgfs.asp?unique=1237846510682&nof_id=21 http://www.hopkins.co.uk/projects/_selected,100/