Kew's Millennium Seed Bank - Fascinating facts

Entada gigas ©Robin Foster - The Field Museum, Chicago.

Did you know...

• Inspiration for the shape of Kew's Millennium Seed Bank was obtained from the shape of the pod of the Sea Bean (Entada gigas).
• The building's footprint is about 5,000m².
• The design is based on a series of 14.4 m x 7.2 m areas linked by circulation routes.
• The main building materials used are fair-faced concrete, York stone, painted steel and structural glass.
• The concrete barrel vaults are covered by zinc tern-coated stainless steel. Together these provide thermal mass to assist in energy control.
• The services run on platforms underneath one half of each vault roof.
• Due to the difficult substratum (fissured sandstone), the foundations are underpinned by substantial friction piling.
• Although parts of the building, such as the seed vault, have been designed with a 500-year life in mind, the structural layout of much of the rest of the building can be changed.
• The seed vault has a floor area of about 930 m² (about 1.5 times bigger than the main Orange Room interpretation area sat over the top of it). With an internal height of just under 5 m, if filled wall-to-wall the seed vault could hold 100,000,000,000 rice grains. Alternatively, it could accommodate about 30 red London double-decker buses (a tight fit and access permitting!).
• Within the seed vault are four 48 m² prefabricated cold rooms operating at -20 °C. These are accessed from a drying room running at 10% RH and 18 °C which, in turn, is accessed through an air lock. Fully fitted out, the vault could hold a further five such cold rooms with the capacity for perhaps as much as 40% of the world's seed-bearing species (with an average of just under two accessions of each).

The Seed Bank vault under construction

• The benefit of storing the seeds underground is mainly one of reduced energy use in the summer. There is also the benefit of increased security. Potentially, being underground increases the risk of flooding, however the substrate (see above) and location reduce this risk. Nevertheless, the vault contains two sumps with pumps. Furthermore, the cold rooms are built up on a block base; water pouring from a tap (at 7 litres per minute) would take about three weeks to reach the cold room floors in the absence of the pumps.
• The thickness of concrete in the vault roof and walls reduces the effects of radiation damage to the collections in the event of a nuclear catastrophe. The air to the dry rooms is monitored continuously for radioactivity and is closed off if any is detected, thereby preventing radioactive dust entering the vault and damaging the seeds.
• The building has its own generator. Though it is desirable to keep the cold rooms at -20 °C, because the seeds are dry and well packaged short power cuts have relatively little effect on their longevity. The main purpose of the generator is to support the germination incubators, the two drying rooms, the laboratory equipment and the residential accommodation in the event of a power cut.
• The cold rooms are chilled using a state of the art Pack system comprising seven scrolling compressors allowing many levels of control that help save energy. Waste heat from the unit is recovered for domestic hot water.
• The building has 14 bedrooms for visiting scientists, a library, and a seminar room holding up to 100 people.
• The curved structure of the 'glass' house is actually made of polycarbonate. This facility is divided into four chambers, two of which can be controlled to give the conditions experienced by plants in many of the world's drylands. They have shading, black-outs, fogging, supplementary lighting and extra heating. The other two chambers have standard glasshouse features.
• The building was designed between 1995 and 1997 and constructed during 1998-2000.
• It was designed by the architects Stanton Williams. Other key companies were James Longley (main contractor), Michael Barclay Partnership (structural engineers), Gordon Fanshawe (quantity surveyors), Pearce Buckle (service engineers) and Hornagold & Hills (project consultants).
• At the peak of activity, 120 contractors were directly involved in its construction.
• It was opened by HRH The Prince of Wales on 20 November 2000.
• The building is named the 'Wellcome Trust Millennium Building' in recognition of the two key sponsors of the construction costs - the Wellcome Trust and the Millennium Commission.
• The building cost £17.8m to construct.

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