External Cladding System :

The building’s exterior cladding system consists of full glazed , double-skinned facade comprisingApproximately of 5,500 flat triangular and diamond shaped glass panels.(Profinder).These metalAnd glass prefabricated panels are fixed to the diagrid.

The elements of the facade consist of :

Openable glass screen Perforated aluminium louvers ( internal sun-screen ) A column casing of aluminium Facade frame of extruded aluminium

The glazing to the office areas consist of a double – glazed outer layer and a single- glazed inner screen.Sandwiched in between is a central ventilated cavity which reduces heating and cooling requirements.Its performance can be turned to maximise benefits that the prevailing internal and external environmentMight have to offer. The solar-control blinds intercept solar gain before it enters the office environment.

Majorty of the cladding system of St Mary Axe consist ofglazing. Glazing to the first 38 levels of the building are tobe aluminium framed, while the domed structure on theTop is to be frameless glass.The glass used for the external cladding is to be producedand installed with good characterises in subject to windLoading , human impact , safety , security and the UVElimination.Glazing to be used for the cladding is Solarplus low E TwinGlaze unit by G.James. It is chosen for its superior thermalperformance. Glass is to be clear in colour and grey glassFor the atrium and dome.

The upper three levels of the building from Level 38 provide corporate facilities for Swiss Re and other tenants , including private dining rooms , restaurant and an upper viewing Mezzanine offering 360 degree views over London. These levels are enclosed with a steel and glass dome structure of 30m diameter , rising 22m from its support on the top of the perimeter diagrid.The dome steelwork is a fully welded lattice ofintersecting fabricated triangular profiles.The efficiency of this structural arranement results in very minimal steel elements that are only 110m x 150mm in section.

The internal structure of the building comprises conventional steel beams and columns with composite profiled decking floors.

The total weight of steel used is approximately 11,000 tones.

Sources:

http://www.slideshare.net/adadarmon/swiss-re-building-london

http://www.victorbuyck.be/uploads/projects/doc_14.pdf