SW OCTOBER 2015 - Page 24

INDUSTRY NEWS A re-loaded powertransmission tower in New Zealand It has been seen that once the original HDG zinc has depleted to a certain minimum thickness, these structures, or their components, would be difficult or very expensive to replace, due to the logistics involved, and so it is easier and much more cost-effective to have the original galvanising layer re-loaded’ with Zinga. This was one of the main conceptions borne in mind when the Zinga material was originally developed 36 years ago, and the “re-loading” or “re-charging” of the original HDG zinc on many different structures is still one of the main precepts in the use of ZINGA®. So they decided to film galvanise them instead, and by using spun-galvanised fasteners, there are no areas anywhere on the entire construction where there could be any galvanic activity taking place. Film-galvanised box-beams on the upper section The FG beams can be exposed to rain and weathering within an hour or so of the zinc being applied, depending on ambient conditions, and so handling and storage of the beams is easy, with no problems. A view of the structure before cladding was added The transmission tower shown here on the left is one of hundreds that have been re-loaded in New Zealand, and there are many more towers in Portugal, Taiwan and Australia that have already been re-loaded. An inspector checks one of the box beams After weathering, the film galvanising looks like hot-dip zinc. The most recent large project to illustrate that ZINGA® can replace HDG when it is not possible or practical to use hot-dipping methods, is the Runcorn Thermal Power Station near Liverpool, where the vertical H-beams were all finished in HDG. The 65 box-beams, each measuring 20 metres in length and each weighing 20 tons, were finished in film galvanising. The architects refused to allow the beams have a row of large de-gassing holes cut into the bases of the beams in order to have them HDG coated. 22 After the cladding has been added One major advantage of the film galvanising system ZINGA® is that it can be re-loaded with itself after one hour, one month or even after 20 years. There is a difference in colour and surface finish between ZINGA® and HDG, but the protective galvanic voltages of the two galvanic coatings are identical. On several occasions, ZINGA® has been used to ‘build-up’ layers of HDG because they did not pass their thickness evaluation according to ISO BS 1461 (and is now ASTM - A123 in USA). They can be handled (even roughly) in exactly the same manner as HDG beams are, and like those beams, they can also suffer scratches and scrapes with no effect whatsoever on the corrosion-protection properties to the steel underneath. There is a difference in colour and surface finish between FG and HDG, but that is about all really. A delegation from China, headed by Chairman Ye, visited two or three countries in Europe to look at film galvanised coated steelwork. Due to logistics and timing of the visit, they were not able to visit the site of the Runcorn Thermal Power Station, and this was the one power station where Zinga had been used throughout the construction on dozens of box-beams, and the members of the delegation had been very keen to see the Zinga operation in a working environment, and also because it was ‘working’ in a marine location next to the sea, as is also the case in Lufeng. October 2015 Telephone: 01243 770 726 Email: sales@zinga-uk.com Visit: www.zinga-uk.com read online @ www.surfaceworld.com