South Hook LNG Inauguration Dome

Tectoniks Ltd., Shrewsbury, Shropshire, United Kingdom

The project involved the design, construction and installation of a 35m (115 ft) diameter inflatable dome to serve as the venue for the inauguration ceremony for the South Hook Liquid Natural Gas (LNG) terminal at Milford Haven in South Wales, United Kingdom.

The dome would be surrounded by aluminium framed marquees that would house reception areas and exhibition spaces. The entire complex would be installed on a temporary deck located in the contractor’s car park at the South Hook terminal.

The site for the event was a location on the South Wales coast with a reputation for high winds. One of the client’s primary concerns about using such a large inflatable dome was its structural performance, particularly in high winds. The client also required the dome to block out all natural light so the interior lighting and visual presentations would have maximum impact. Noise levels from the pressurization system were also a concern.

The dome had to be installed on temporary decking on a site with a significant slope. The deck measured 63 meters (207 ft) by 61 meters (200 ft) and was not designed to withstand the weight of forklift trucks and cranes. The dome, therefore, had to be capable of being installed using manpower alone. The solution was to design the dome to be supplied in five pieces, each weighing approximately 650kg (1,430 lbs). Each section was lifted from the delivery truck onto the edge of the deck using a forklift truck, from where it was dragged to its position by hand. A new method of joining the sections of the dome on-site had to be devised so the assembled dome looked like one continuous structure. The solution was to use two layers of fabric keder that were stitched and heat sealed to the dome. The fabric keder strips on adjacent dome sections were then joined using aluminium keder track cut into sections to follow the curvature of the dome. A separate fabric weather strip was concealed between the two layers of keder to provide additional weatherproofing.

The decision to design the dome in five sections was also made to provide five independent pressurized zones, each with its own pressure control system. In the unlikely event of a failure of one section, the remaining sections could support the failed section and prevent the dome’s collapse. Since the dome used a unique welded construction, it required little air to maintain pressure once inflated.

Despite windy conditions throughout the installation and during the event itself, the dome performed flawlessly.