Proper corrosion protection is critical in steel construction. Protective coating systems on bridges and other steel structures that fail due to poor durability or through incorrect specification are expensive, inconvenient and may have a negative impact on public health, safety and the environment when these systems are repaired or replaced. A simple means of specifying protective coatings reduces these risks.
The single coat inorganic zinc silicate is a very effective and economic means of corrosion protection.
However it does require quality application and inspection to deliver its outstanding durability. A new version of AS 4848.1 (Application specifications for coating systems – Single coat inorganic (ethyl) zinc silicate – Solvent-borne) has been released by Standards Australia which should make it much easier for engineers, architects and others to specify the use of this coating system. Users can simply include a sentence on drawings or similar documents along the lines “Apply a single coat inorganic zinc coating to AS 4848.1 IZS1 to the structure” without having to write a full specification, knowing that the standard covers the necessary requirements for surface preparation, application and inspection.
An earlier version of this standard has been available for a number years but the system differed from those given in AS 2312 and there were a number of errors and omissions which made the standard less than ideal.
These have been corrected in the new version. Furthermore, it now provides three coating systems (IZS1 – 75 microns for most atmospheric applications, IZS4 – 125 microns for severe atmospheres and HR3 – 50 microns for high temperature applications), identical to those given in AS 2312.1. The standard does allow for modification if required. For example, the specifier may wish to include a detailed scope of work or stipulate certain commercial products only. These can be included in an additional note or construction specification.
Easy availability of a simple, economic coating system such as that covered by this standard is vital for the long term performance of steel structures and well as reducing maintenance expenditure.