ARCHIVE

Article from issue 7+8/2006 »Lightweight Construction + Systems«

Suvarnabhumi International Airport Bangkok - Engineering, Manufacturing and Installing the Membrane roof

technology p. 824 - 825
Author Heeg, Manfred |

Triple-layer membrane roof
Because the requirements could not be fulfilled with a single membrane the project team developed three layers separated by air pockets. The technical optimisation, material development and detailed planning of the membrane roof was undertaken by Hightex. The outer membrane, weighing 1200g/m2, is of glass fibre with a PTFE-coating, distinguished by high reflectance, high tensile strength, dirt-repellence and durability. The middle layer serves primarily as sound protection: 6 mm transparent PC sheets are attached to a steel cable mesh. At 7.2 kg/m2 for the PC sheets, the entire roof construction attains a sound reduction index of 35 dB (ill. 2).
Producing the inner low-e membrane
The innovation occurs in the inner membrane; its metallic, shimmering underside is visible from the interior. (ill. 1). Glass fibre – furnished with a low-e coating on the side facing the interior – was selected as carrier. The membrane combines excellent visual low-e and acoustic absorption properties with translucence. First the open-weave glass fibre, with a gross weight of ca. 280 g/m2, is primed on both sides with an ultra-thin layer of transparent PTFE terpolymer. Then an aluminium coating (ca. 100 nm) is applied to the inside. The completed membrane weighs 330 g/m2, the tensile strength is 3250 N/5 cm.
Manufacturing the membrane
Large halls, totalling 9000 m2, were rented near the airport grounds; the largest free-span hall (32 ? 180 m) was furnished with the necessary welding and testing equipment (ill. 3); two others were used for storage and preparation (ill. 4). Five manufacturing specialists directed and supervised a team of 120; they produced 210 interior and exterior membranes in precise coordination with the construction teams. Membrane specialists led 6 independent assembly teams. They worked simultaneously at different spots along the concourse. The 108 sectors were completely enclosed in the nineteen-month construction period.