GREEN AIRPORTS
by Deborah Singerman, Candice Lim and Caroline Wang

Naturally lit, transparent, and well-louvred for minimal solar glare and heat gain; energy efficient; and landscaped with greenery—three recently completed airport terminals seem to be aiming for green in similar ways.

HEATHROW TERMINAL 5
Variously described as “Europe’s busiest airport” and “the world’s busiest international airport”, Heathrow, on the outskirts of London, has a reputation to live up to. However, it has also been tagged with other less flattering labels—chaotic; badly organised; dowdy; and a nightmare to get around.

The new £4.3 billion (S$11.6 billion) Terminal 5 campus development includes the main terminal (Heathrow’s first major new terminal for over 20 years), two satellite terminals (the second to open in 2010), a control tower, landscaped motorway link, taxiways, aircraft stands, rail stations for trains to central London and beyond, an airside track transit system and road tunnels to the airport’s central terminal. This massive re-fashioning in appearance and functionality is aimed at turning arrival and departure into a pleasurable passenger experience.

T5 was officially opened by Queen Elizabeth II in March 2008, almost 20 years after the architects, Rogers Stirk Harbour + Partners (RSHP—formerly Richard Rogers Partnership), won the competition, and began the master planning and shell-and-core design. It hit the headlines for all the wrong—and unsustainable—reasons: baggage handling problems, IT system breakdowns, flight delays and passengers kipping wherever. At the time of writing, BAA and British Airways had deferred moving long-haul services from Terminal 4 to T5 until June but things generally were operating normally. Come what may, the bright, airy terminal—all 300,000 square metres with an expected 30 million passengers annually—demands attention. While it is too early yet for operating costs and monitored performance figures, sustainability, as the architects say, “has been a core value in delivering T5”. It is also a commitment from the client, airport owner and operator BAA, and from T5’s exclusive airline, British Airways.

T5 needed to be compact and sit within a constrained footprint as a result of a public enquiry completed in 1999, which insisted that the site area must not cover surrounding green belt land as originally intended.

RSHP, led by project director Mike Davies, wanted “a sustainable, long-life, loose-fit concept allowing for flexibility, growth and change over time”. They have created a large floor plate concept with, in the architects’ words, “an unencumbered large-span envelope” that leads to just the flexible, internal spaces required, and easily dismantled and reconfigured facilities within a freestanding steel-framed structure. The immense, elegant “curved floating roof”, up to 37 metres high with a clear span of 157 metres, is supported by slim columns at the perimeter edges.

In line with many airport terminals—indeed new, large commercial buildings the world over—RSHP have favoured natural light and transparency throughout the passenger areas, which are mainly on one level though extending over two levels at both ends of the building. The plant room and baggage handling are below. Open and fully glazed louvred façades, using a brise-soleil shading system, add to the effect, allowing passengers to see across the airport while also limiting glare and solar gain. As well as improving the overall ambience within the terminal, all this reduces the need for artificial lighting especially during the day, and optimises energy use. A control system switches off or reduces lighting levels within the terminal when parts of the building are not in use. Remote controlled energy metering within this system is aimed at improving energy management, saving energy while also allowing the new terminal to meet Part L of the British Building Regulations controlling carbon emissions from buildings created by their environmental services. The Society of British Aerospace Companies Chief Executive Ian Godden reiterated the industry’s ongoing Sustainable Aviation strategy to cut noise and carbon dioxide emissions by a further 50 percent of 2000 levels by 2020.

T5 uses waste heat to reduce its gas consumption. An energy centre is connected to a combined heat and power plant, which generates 15 megawatts of electricity distributed on the Heathrow high voltage distribution system. Waste heat associated with this process is recovered and distributed back to the energy centre where it will supply approximately 85 percent of T5’s heat needs. This is expected to reduce gas consumption by 85 percent with a corresponding reduction in carbon dioxide of 11,000 tonnes per annum. Hydrochlorofluorocarbons (HCFCs) have almost been completely eliminated from the T5 project. It was decided early on that the most efficient and environmentally acceptable solution to cooling the building was to use a centralised chilling system, with the chilled water being generated by high efficiency ammonia chillers to avoid the use of HCFCs, which have a very high global warming potential.

Deciding that natural ventilation was impractical because of aircraft noise and pollution, the architects used a displacement air-conditioning system developed by Arup, the project’s structural engineer. This system distributes air out to the floor plates, directly where it is required, re-circulating air and minimising use of fresh air. Air quality and temperature is measured by T5’s building management and control system.

Groundwater boreholes and T5’s own rainwater harvesting scheme supply water for non-potable uses such as toilet flushing, irrigation, energy centre cooling and vehicle washing. The system is able to capture and reuse 85 percent of the rainfall that falls on the entire T5 catchment. Demand from the public water supply is expected to be reduced by 70 percent. Alongside additional water-saving devices such as dual-flush toilets and taps; showers with automatic on and off sensors; and aerated flow, the passenger terminal is predicted to reduce consumption of potable water from 40 litres per person to 17 litres per person.

BAA has a strict materials strategy, focusing on sustainable construction materials and minimising the use of non-sustainable or harmful materials. For instance: only Forestry Stewardship Council-approved timber from sustainable sources was used; over 300,000 tonnes of aggregate was processed and recycled on site from demolition materials and waste concrete; crushed green glass from domestic household recycling banks was used as a base for T5 site roads; around 6.5 million cubic metres of earth was moved during the project, and then used to backfill excavations and landscape the terminal; and waste materials were segregated on site and 85 percent of construction waste has been recycled.

The distinctive wavy wall and landscaping, including over 50,000 plants, semi-mature native shrubs, trees and evergreen groundcover shrubs, help to contain airport noise, reducing the impact on surrounding communities.

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