lgn0709

Specialist recommends laminated glass for curtainwall design

Trevor Hennessey of Hennessey Glass and Aluminum Design Pty Ltd. in Brisbane, Australia, has over 35 years' experience in curtainwall design and installation. He has designed and built numerous multi-story buildings, using both stick and unitized curtainwall systems, in cities throughout Australia. The following is an extract from a presentation given by Trevor Hennessey at a series of architectural seminars held in ASEAN countries by DuPont, Hennessey Glass, Leybold Systems GmbH, Peter Lisec GmbH and Dr. Leon Jacob.

Trevor Hennessey

"Curtainwalls are popular in Asia since they are fast to build and are the best way to waterproof buildings against the heavy rain and high winds we can experience. As a specialist in the field, I always advise architects to check the type of glass they are going to use in curtainwalls very carefully because of the danger of tempered glass breakage, either due to nickel sulphide inclusions or from damage to the glass on the outside of the building."

The Parkroyal Hotel, Queensland, Australia uses laminated glass in a high-rise curtainwall.

"I strongly recommend that laminated glass should be used for curtainwalls in high rise buildings. Specifically, architects should use insulating glass units in which the outside lite is laminated solar-reflective heat-strengthened or laminated solar-reflective tempered glass, and the inside lite is either tempered or laminated glass."

"This recommendation comes after witnessing numerous legal disputes where the architects, builders, engineers and consultants on curtainwall projects are all held liable when spontaneous breakage occurs. The extra cost of installing laminated glass containing either heat-strengthened or tempered glass, rather than monolithic tempered glass in the outerlite of the glazed unit equals less than one-tenth of the legal fees that many architects have had to pay in Australia and the USA in recent years due to spontaneous breakage in curtainwalls of tempered glass!"

Laminated glass stays safely in the building façade

"If laminated glass is damaged by any means – for example by building maintenance machines during the cleaning of the windows – and this condition is then exacerbated by high winds or sudden changes in temperature, leading to breakage of the glass – it will stay in the building façade. This is critically important, since, in similar situations, tempered glass will break into small fragments and then fall down the height of the building in interlocking clumps, with the potential for serious injury to pedestrians."

"The safety factor, using laminated glass, is optimized if the glass is structurally glazed in a factory, in a unitised fashion, using a fast-curing, silicone sealant. The risk with stick systems is that these are usually performed on-site and, as everyone in the construction industry knows, quality control is easier to enforce in a factory environment than on-site."

Laminated glass curtainwall in new Queensland hotel

"Towards the end of 1996, our company completed work on the new Parkroyal Hotel on the Gold Coast of Queensland. The windows are insulating glass units, supplied by Pilkington Australia, in which the outside lite of glass is laminated heat-strengthened grey glass with a TS30 reflective coating on surface three of the laminate, an the inside lite is laminated clear annealed glass. The reflective coating within the laminated glass achieves solar gain reduction with consequent savings in air-conditioning costs. Clear laminated glass was used on the inside of the panels for optimum safety. Insulating glass units like these, containing laminated glass, also result in optimal sound reduction."

"So when I sit down with architects to discuss curtainwall high-rise projects, I always tell them that laminated glass is the right product for the job."