Elephants in the room

Foster + Partners apply great design to create a better home for one of the world's favourite animals.

The roof provides plenty of natural daylight. (Foster + Partners)
The roof provides plenty of natural daylight. (Foster + Partners)

Foster + Partners apply great design to create a better home for one of the world's favourite animals. James Boley finds out more.

Most architects will, at some stage in their career, have to work for a client with very particular demands. Very few, however, will find themselves designing a home for end users that are 4m tall, weigh 5000kg and never forget-yet that's exactly the situation Foster + Partners (F+P) found itself in when commissioned by Copenhagen Zoo to design a new house for its seven Asian elephants.

A far cry from the zoo's somewhat inauspicious beginnings in 1859-the animals and habitats at that time included chickens, rabbits, a seal in a bathtub and a turtle in a bucket-F+P's Elephant House is a facility that revolutionises zoo structural design and sets new standards for animal welfare.

Once you get beyond the client requirements, it's like any other project.

Taking Le Corbusier's proclamation of "the house is a machine for living in" literally, the new home is tailor-made to suit the day to day needs of the elephants, keepers and visitors.

Brief encounters

The Elephant House is F+P's first zoo project, and at first glance, it seems, at least conceptually, to be a million miles away from its signature projects of 30 St. Mary Axe or the Reichstag building. However, whether designing for people or pachyderms, the fundamentals remain the same.

"Once you get beyond the client requirements, it's like any other project. It's designing a tailored response to the brief, and the construction technology is the same as on any other project," explains John Jennings, project architect at Foster + Partners.

Design of the Elephant House drew on the wealth of scientific research the zoo has conducted into elephant behaviour, allowing Copenhagen Zoo to provide a very extensive brief, says Jennings.

"They wrote us an extremely detailed brief that went into the biology and behaviour of the elephants, their reach, height, weight, what they like, what they don't like and what is necessary for their health," he says.

As part of the research, two of Jennings' colleagues even spent a day working as keepers in order to understand the requirements of the building from the perspective of zoo staff. He describes the building as similar to a theatre.

"As well as being there during the day to entertain the public, they do have a very complex daily schedule for the keepers, for cleaning, maintenance, training and feeding-all that goes on behind the scenes but has to be smoothly integrated into the schedules," says Jennings.

The original building, a Nordic Classical red brick structure dating from 1914, was simply too small for efficient use.

An elephant eats more than 100kg of dry food per day, which in the old structure had to be moved by wheelbarrow.

"The whole keeper area has been designed for vehicular access to the back of house areas, which makes transportation of feed and waste a lot easier," says Jennings.

A running bull elephant can put a 15 tonne horizontal load onto a wall, which limits the palette of materials we can use.

Structurally, the architects were limited in the materials they could use because of the special requirements of the elephants.

"A running bull elephant can put a 15 tonne horizontal load onto a wall, which limits the palette of materials we can use," says Jennings. The main building structure is reinforced concrete to a depth of 300mm over a steel frame, split into two double-glazed domes.

All services and light fittings have been located either behind steel plates or out of reach-an elephant's trunk can reach 2.5m horizontally and 6m vertically, and their intelligence makes them naturally very inquisitive, or disruptive, depending on your perspective.

Attractive design

The design had to balance the functionality of the structure with the need for the building to act as a visitor attraction. The centre of the building is the 'exhibition' area, which allows visitors to interact with the elephants and learn from information boards.

The ramp is designed as a processional route with a 1:25 gradient from top to bottom. This allows for a constant flow of people and also ensures that facility is accessible to all. "No one has to take a special route that might discriminate against anyone," says Jennings.

Surrounding the visitor ramp are the two domed spaces in which the elephants live, while the outer layer of the building contains the technical areas and keeper walkways. "The animals are sandwiched between the visitors and keepers. It makes the organisation of the building very simple," says Jennings.

The domes themselves are designed to mimic the natural habitat of the Asian elephant. One dome is for the female elephants and juveniles, while a separate, smaller dome is designated for the larger bulls.

"In the wild, the bull elephants live apart from the main family herd," explains Jennings.

The separation is important in maintaining visitor satisfaction and safety for the female elephants. Bull elephants that are 15-20 years old, enter a state called musth, wherein they become extremely sexually aggressive. "If you see a bull in musth, it's very smelly and they don't look particularly attractive," says Jennings.

The two-month musth period usually sees bulls excrete a testosterone-rich fluid from largely swollen temporal glands. "The zoo prefers not to put them on public display because the public could wrongly interpret them as being mistreated or stressed."

The bull dome's viewing windows can therefore be shut, safeguarding vulnerable female elephants and allowing the public access to only the more attractive herd.

Foreign climes

Obviously, the major difference between the Asian elephant's natural habitat and that of Copenhagen is climatic. Average winter temperatures in the Danish capital frequently hover around 0ºC-decidedly uncomfortable for an animal used to the tropical temperatures of Thailand.

The sandy floor can be heated, which also means it dries quickly after cleaning. This, in conjunction with the double-glazed domes, ensures the stable areas are kept at a pleasant 16-22°C. A misting system controls the humidity, preventing the elephants' skin from drying out.

Climate also drove the aesthetics of the building. "When there's snow on the ground, mist in the air and a completely white sky, displaying elephants in a grey concrete building would have visually seemed rather cold," says Jennings.

To combat this, a warm terracotta pigment has been added to the concrete walls. This has the added benefit of mimicking the colours of the elephants' natural habitat and echoing the red colour of the original house, which is a protected building.

The domes play a further role in climate control and simulating the natural habitat. The domes contain a ceramic frit to reduce thermal gain and, rather than use the conventional gradient shading provided by dot fritting, F+P designed the frit in the shapes of leaves.

The fritting pattern was created by sampling four species of Asian tree. A computer script was written to rotate, scale and randomly populate the roof, so that no two leaves are the same. The overlapping pattern provides naturalistic dappled light, mimicking the natural habitat and protecting the elephants from sunburn.

Efficient elephants

F+P is probably most famous in the GCC for the design of Masdar City, the zero-carbon, zero-waste city to be built in Abu Dhabi. Despite some limitations, the design of the Elephant House is also aimed at reducing the overall carbon footprint of the project. Heat insulation is provided through inert glass foam, which is made from recycled glass and designed to last forever.

However, the biggest environmental gains are made through water conservation. Elephants require a considerable amount of water for washing, yet water prices in Denmark remain some of the highest in Europe.

"We looked at harvesting rain water from the glass domes but decided that during the summer, that's a very inconstant supply," said Jennings. "We found a much better source of water from the groundwater."

The area has a high water table and because the Elephant House is located on the side of a hill, the perimeter often needs dewatering. This water is then collected and filtered, making it suitable for elephant washing and drinking.

A healthy home

Since the Elephant House opened in June 2008, vets at the zoo have already reported it has had a positive impact on its inhabitants. The healthier sand surface has resulted in the elephants getting more exercise, which has allowed them to avoid the elephant equivalent of athlete's foot.

The improved health and home has also resulted in happier elephants in the urban zoo. "They've got a beautiful new facility and it's obvious from the way they behave, when you see them playing in the paddocks and lake, they're very happy," says Jennings.

"It's very rewarding to improve the quality of their lives."

Client: Foundation Realdania for Copenhagen Zoo

Architects: Foster + Partners

Structural Engineers: Ramboll with Buro Happold

Services: Ramboll with Buro Happold

Landscape Architect: Stig L Andersson Architects

Cost Consultant: Davis Langdon LLP

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