Dow Corning structural glazing sealants, supplied by a.b.e. Construction Chemicals, are being used in the installation of the facades on the 139m high Portside Tower, Cape Town Foreshore's new icon which, on completion, is destined to be the tallest building in the Cape Town CBD. a.b.e. is part of the Chryso Southern Africa Group.
Samantha Ferreira, a.b.e.'s Brand Manager: Silicones, Sealants and Special Adhesives, says four Dow Corning products are being supplied to Compass Glass, and its sister company the Mazor Group.
Compass Glass – an a.b.e. Quality Bond applicator – specialises in the beneficiation, fabrication and distribution of glass, including the manufacture of laminated and toughened safety glass, and double-glazed units.
The four Dow Corning products being used by Mazor Engineering, the facade sub-contractor to the main Contractor, Murray & Roberts, for the R1,6bn development jointly initiated by Old Mutual and the First Rand Group, are:
- DC 993 structural glazing sealant, a two-component neutral curing silicone formulation specifically developed for the structural bonding of glass, metal and other building components.
The sealant has been successfully used in prestige applications all over the world, including 15 Alice Lane Towers in Sandton; the Arabella Sheraton Grand Hotel at the Cape Town International Convention Centre; the Old Trafford sports stadium in Manchester; and the British Airways London Eye, in London.
- DC 3362 insulating glass sealant, also a two-component neutral curing silicone formulation for the manufacture of high performance glass units, typically used as secondary sealant for insulating glass in structural glazing. DC 3362 secondary sealants are capable of withstanding different climatic loads and have exceptionally low heat transmission. The product was used for the external façade of the world's most inclined high rise building: the Capital Gate in Abu Dhabi.
The building has about 12,500 glass units which form more than 720 diamond shapes;
- DC 813 C, a low modulus, neutral cure silicone sealant particularly suitable for weather seals, expansion and perimeter joints in buildings, both internally and externally. The sealant has a joint movement capability of around 50% and provides strong adhesion to a variety of substrates; and
- DC 1200 OS primer, a UV-traceable air-drying primer used to improve both the quality and speed of adhesion of the structural glazing sealants to a wide variety of substrates. The incorporation of a small amount of UV tracer allows for the tracing of correct primer applications by using a UV lamp.
Portside Tower, and its impressive structural glazing, face the challenge of coping with the Cape Town Foreshore's notoriously high winds, sometimes blowing at over 110kms per hour in very high hot summer conditions.
Chris Sharpe, abe. Technical Sales Consultant in Cape Town, says the client has been exceptionally impressed by the performance of the Dow Corning structural and insulating glazing sealants.
"In fact, Compass Glass and its sister company, Mazor Engineering, have commented favourably on the high level of technical support and constant monitoring by both a.b.e.'s and Dow Corning's technical management," he says.
The 32-storey Portside Tower - jointly designed by DHK and Louis Karol Architects – will comprise offices, retail outlets, coffee shops, and a state-of-the-art banking hall on the ground floor. The building will offer over 52,000m2 of office space, 1 200m2 of retail and banking space, and nearly 1,400 parking bays.
The building's 'green' design is aimed at achieving a 5-Green Star SA Office rating, as administered by the Green Building Council of SA of which the Chryso Southern Africa Group is a member. Among the skyscraper's many environmentally friendly features is that all 33 floors of the glazed façade have been designed for disassembly for recycling at the end of the building's operational life.
Construction of the fast-track project, scheduled for completion around the end of this year, is aided by a locally developed hydraulically powered self-climbing formwork system that climbs upwards as the floors are constructed.