A POPULAR CHOICE
Metal/Steel tanks have been popular for years and continued development of new colours, shapes and sizes has ensured they still are. Some years ago they were made from rolled sheets of galvanised iron and riveted and soldered to prevent leaking. They were the backbone of water storage the world over. Now the plain metal tanks are typically made from ZINCALUME®, and the coloured tanks are made from AQUAPLATE®.
TRADITIONAL ‘GALVANISED’ TANKS
There are some very important factors to understand when it comes to metal/steel tanks. In the past the humble tin tank has been described as a “galvanised tank”. Galvanising is the process of applying metal to metal and the “galvanised tank” is made from zinc galvanised to steel. These “galvanised” tanks could be soldered. Solder consists of a combination of lead & tin which is melted with a hot iron and applied to a joint was prepared with spirits of salts. These metals were similar to each other, deemed compatible and adhered to each other under heat.
Then along came ZINCALUME®, a high tensile roofing product that revolutionised the roofing industry, it was strong, came in long one-piece sheets that reached from the roof ridge to the gutter without a join.
The emergence of ZINCALUME® (primarily a zinc and aluminium mix of metals “galvanised” to steel) as a popular roofing material brought problems for the trusty galvanised water tank. In the early days there were instances where new ZINCALUME® roofs were installed and within months the galvanised water tank had rusted out. The tank would break out in brown freckles and in a short time the freckles would begin to join up and the tank would collapse and the owners would then realise that the freckles were rust. The freckles/rust were caused by electrolysis. Electrolysis is a result of metals of opposing make up being joined together, in this case with water, which then creates an electrical field like a battery. The electrolytic action corrodes away the less noble of the two metals and in this case the galvanised tank.
Nowadays electrolysis is still possible where a building still has a galvanised (zinc) roof which supplies water to a ZINCALUME® tanks.
AQUAPLATE® – A NEW ERA
Steel tanks are popular today, they are actually made from AQUAPLATE®trademarked by BlueScope Steel Ltd. The AQUAPLATE® tank is a top of the range metal tank. It has a food-grade polymer skin bonded to its inner surface which helps ensure your water tastes clean & fresh, free from any tainting from the tank itself. BlueScope Steel warrants the performance of tanks made from AQUAPLATE® steel for 20 years (against corrosion to perforation), subject to approved installation, sound construction and storage of potable drinking water. Warranty conditions apply. Tanks made from AQUAPLATE® steel must have a top, preferably with a manhole cover in place at all times. That’s because the polymer coating is not resistant to prolonged exposure to direct sunlight. A complete cover also prevents the growth of algae and excludes vermin. The construction method used for AQUAPLATE® tanks is such that joints can not be soldered so adhesive sealants are used on the inside of the tank to cover the seams, some tank makers also sandwich the sealant between the overlaps of the sheets.
Metal tanks are also available using a modular construction system which ensures strength, water quality and makes delivery onsite more manageable. These modular tanks can be built to store significant water volumes and are extremely popular in rural and commercial applications.
Extremely strong tanks with polyethylene tank linings to prevent corrosion and ensure water quality.
Site Preparation : A concrete base is required or an approved tank stand
In Ground : No
Guarantee : Ask your supplier for a written guarantee for both the material & the workmanship.
Repairable : Yes, seams can be resealed by the manufacturer.
COLORBOND®, ZINCALUME® and AQUAPLATE® are registered trademarks of BlueScope Steel Limited
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