Gulf Construction Online - Cladding gives flight to aerodynamic design

Dubai Airport Expansion

Cladding gives flight to aerodynamic design

The exterior building system gives the new concourse its highly-distinctive character based on aerodynamics. Al Abbar Aluminium, which was tasked with supplying and installing the high-spec system, elaborates on how it has successfully met the challenge.

01 February 2000

The sleek 800 m long by 80 m wide by 30 m high structure of the new concourse, designed by International Bechtel, presented a considerable challenge to Al Abbar Aluminium, which was entrusted with the work on the external building system (EBS).

Although no strangers to the technical requirements of modern high-performance buildings, Al Abbar realised that the concourse building required special considerations, given its location and use.

A structure in an exposed location, subjected to extremes of climate and the emissions of modern aircraft, demanded a super-insulated envelope to allow strict control of an interior environment over its complete length.

Al Abbar Aluminium chose curtain-wall cladding. A design consultant from Texas was selected to provide the system's design with Al Abbar's own local fabrication and installation of the external cladding and glazing.

This required a change from the original three-skin roof concept to a two-skin fully-sealed panel-clad roof system with a conventional capped strip curtain-wall system running the length of the building, fully glazed gable-end walls and a series of feature skylights atop the roof. The contract further incorporated 27 glazed and panel-clad passenger loading bridges.

The exterior building system comprises a skin of profile decking beneath an aluminium grid framing with a fully sealed exterior composite panel system. Between the decking and the exterior panels are multiple layers of mineral insulation with vapour barriers to eliminate the transfer of heat and the risk of moisture build-up. For the exterior panel system, Al Abbar selected Al-Clad, a superior composite sheet cladding manufactured by Mitsubishi Chemical Corporation of Japan. Al-Clad combined the flexibility of a rout-and-return panel system with a fire-resistant, impact-resistant and resilient fluorocarbon coating finish, Lumiflon.

The finish was particularly important when considering the harsh Gulf environment, the particular environment created by air traffic and the need to maintain prime condition during a greatly extended life. Similarly, external aluminium extrusions were coated with a PPG Duranar finish in Al Abbar's facility.

Al Abbar involved Tremco (ME) Limited in the design from the outset and its sealants have been used throughout the EBS system. The quality of sealing was an extremely important factor in the installation to prevent water ingress during periodic rains and periods of high humidity, which are seasonal in Dubai. As a precaution, a secondary drainage system was designed beneath the seals to accommodate the eventuality of joint leakage. Rainwater is dealt with through a system of horizontal louvres which channel the water through internal gutters and into down pipes. For the long elevations of the building, the faceted strip curtain-wall system accommodates high-performance insulated glass units. The purpose-designed system aligns with the curve of the building, giving an aspect which has no vertical glazing and is sloped above and below the mid-line. Extensive use has been made of laminated safety glass to conform with building codes. In the lower portion, the glass slopes outwards above the apron and has laminated external glass, the upper portion slopes inwards over public areas and the inner glass is laminated.

The glazing incorporates blue-green tinted solar control glass, Azurlite, from PPG of the US. All units have a low-emissivity coating applied locally by Emirates Glass including the gable and walls, skylights and passenger bridges. To enhance the solar control properties, shading to the upper glazing and skylights is achieved with the use of ceramic frit lines on the external tinted glass pane. Al Abbar's tempered glass division provided the silk screened fritting and heat strengthening at its facility in Dubai. The glazing will allow passengers a panoramic view of both aircraft and the working airport from the concourse building without the discomfort of heat gain or glare throughout the year.

A spectacular feature of the building is the large central skylights which make the best of the available natural light, again cooled by the same blue-green glass and fritted shading. The central feature gives the building a particular grandeur.

Al Abbar has achieved the daunting task of supplying and installing 86,000 sq m of cladding and glazing in some 15 months, requiring extremely strict control of all elements of work, subcontract packages, fabrication work at Al Abbar's Dubai facilities, deliveries to a high-security site, and very critical installation. The Al Abbar project team worked tirelessly to maintain a tight programme and the result is a testament to their endeavours.

The systems were extensively and successfully tested for performance by TEL at its Dubai laboratory and on site during construction, thereby ensuring that the high standard set by the specification would be achieved or surpassed.

It is estimated that over 11 million passengers will use the facilities in the new concourse building in the year of its opening - few will fail to be impressed by the building's quality and unique, aerodynamic appearance.

Once again, Al Abbar has provided a major contribution to a milestone in the growth of Dubai, an airport which will soon feature among the Top 20 in the world. In completing this prestigious building, it has confirmed a supremacy in the region for quality curtain-wall and cladding solutions.