Northerly approach - British Airways PLC's Compass Center at the Heathrow Airport

Architectural Review, The, March, 1995 by Penny McGuire

Heathrow Airport has been embellished by a graceful glass building by Nicholas Grimshaw & Partners.

British Airways' new Compass Centre (formerly the Centre for Combined Operations) stands alongside but slightly askew the north runway of Heathrow Airport, separated from it by the Northern Perimeter Road and long-term car parks. Its shining glass and bright blue clad exterior reminds you, particularly when seen glowing at night, that one of the largest and busiest airports in the world is otherwise encumbered with a really grim collection of buildings. Decent ones are a rare sight around here.

The shell, core and external works of the Centre were designed by Nicholas Grimshaw & Partners; the interior fit-out was by Aukett Associates. Grimshaws' simple linear arrangement of three blocks, serviced independently, each with a glass atrium 506 and with glass links between, was contrived as a response to the client's request for a building that could be divided easily; for it was originally designed as speculative offices for Lynton, the property development arm of Heathrow Airport Ltd (HAL) with British Airways as the prospective but not necessarily the sole tenant. In the event, BA did decide to concentrate its previously scattered operations and staff in one place; and the building functions like a miniature air terminal, processing thousands of flight personnel and their baggage each day and accommodating the 850 staff occupied with various aspects of administration, planning flights and rotas, briefing the air crews, and so on. BA, which has a reputation for looking after its staff physically, has provided civilised facilities for resting, eating and washing. As in an air terminal, air crew checking in (on the north side) pass through security on the ground floor before proceeding to the upper floors for briefing. The close proximity to the airport posed particular problems. Because of the danger of radar interference, building height was restricted to three storeys (including rooftop plant) and the building had to be placed towards the north of the site. Its form and composition had to be such as to render it almost invisible on the air traffic controller's screens. With aircraft taking off in front of the building every few minutes, other main problems were pollution and noise.

For reasons of speed, economy and fire resistance, reinforced concrete was used for the structural frame which has a raked roof slab and circular columns 514. For a practice which has become known for its virtuoso performances in glass architecture, there seems to have been a happy coincidence here, because compared with other building materials, glass makes a faint impression on radar, can be acoustically efficient (though in this case, Harmon Contract UK 506 was unique in being able to meet the critical specification) and is easy to clean. The shell therefore is largely composed of glass.

At first glance, the envelope looks a glamorous but relatively straightforward exercise in the use of the material, but it is both technically sophisticated and subtle, and in evolving the shape of the building, Grimshaws worked closely with radar consultants. Inclination of the glazed curtain walling 506 on the north and south elevations has the effect of reflecting radar into the ground while at the same time helping to cut out direct sunlight. Detailing such as the aerofoil profiles of aluminium window mullions, aluminium core cladding panels and cast fixings are shaped to reduce the likelihood of radar interference. Again to reduce interference, the building has been made not to line up exactly with the runway; and on the roof, free-standing louvred screens 504 hide the plant from view and act as radar screens.

East and west elevations are clad ruggedly in the blue aluminium panels. On the south and north elevations, inclined acoustic glazing is shaded externally at each level by projecting banks of fritted glass louvres - the principle being that of a wide-brimmed hat. Louvres are tinted blue to impart the impression of summer skies. In making glass the predominant material, the architects have taken the opportunity to make creative use of light and colour Spandrel panels (blue-fritted glass over a solid blue inner pane) glow at night, staircase towers for fire escape at the east and west extremities have outer walls of glass blocks 517, 518 and shine at night like beacons. Inside, the use of glass, often underlit, is a delight. Lift shafts 511 are clad in overlapping glass panels, bridges across the three atria have glass floors and balustrades 504.

This is a deep building (45 m wide). Grimshaws have made use of the inclined glazing 506 to alleviate the effect of developers' standard 2.7 m floor-to-ceiling height. Ceilings, raking upwards at the perimeter, let in more daylight and the design permits external elevations on the north and south to be two thirds clear glazed with one-third spandrel.

The arrangement whereby another team is brought in to design the interior of a new building with a strong architectural imprint is an uneasy one. Airport based clients seem particularly prone to the arrangement and it rarely works well, aesthetic sensibilities varying as they do. Here, as is generally the case, seams show.