INNOVATIONS: PRESENT&FUTURE
Corrosion Protection in Hydraulic Steel Constructions Kornelia Liebisch Gebr. Liebisch GmbH & Co. KG – Bielefeld, Germany
sales@liebisch.com
I
n the hydraulic steel constructions sector, the life expectancy of
conditions are therefore used for comparative analyses. Here,
corrosion protection coatings should be particularly long. A typical
tried-and-tested products are compared with new systems.
example are steel port barriers, often requiring maintenance intervals of
Laboratory tests are described in various standards and norms. In the
20 years. These are subjected to extreme conditions due to the quality
hydraulic steel sector, the guidelines of the German Federal Institute for
of water (seawater), the presence of tidal zones, mechanical loads (shock,
Hydraulic Engineering (BAW) define different test methods for specific
abrasion), and temperatures (ref. Opening photo). That is why protection
types of load. These complement existing test standards. In the field
systems with layer thicknesses of up to 500 μm and more are often
of corrosion protection of steel structures, the ISO 12944 standard
applied. In this framework, the use of epoxy resin or polyurethane as the
should be used, providing state-of-the-art information about the related
main binder is particularly common. Zinc dust is used for the base coat.
practices. Part 6 of this standard specifically describes laboratory tests
The exact composition of the protection system, of course, depends
and test conditions and it includes various methods to assess a protection
on the type of load, the service life and the shape of the structure, the
system. Example salt spray test: a test object with a total coating thickness
coating process in the factory or on site, etc.
less than 250 μm should show no damage after 480 hours of salt spray
In this article, we will discuss the issue of protection systems’ suitability in
exposure at 35 °C, in order to reach the category C3 “long” protection
more detail. How can designers make sure that their selected protection
period. It should also withstand a condensation water load for 240 hours
system meets all requirements? Ideally, they should be able to rely on
at 40 °C without any damage. Correspondingly good cross-hatch results
past experiences with the same system. If it is not the case, a test under
are also required.
real conditions could provide useful results; however, there is often not
Performing laboratory tests calls for high-quality equipment in order
enough time for this. Accelerated laboratory tests under reproducible
to achieve, maintain, and possibly improve high standards. The
© Tom Corser
Opening photo - The Thames Barrier prevents the floodplain of most of Greater London from being flooded by exceptionally high tides and storm surges moving up from the North Sea.
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N.30 - 2019 JUNE - ipcm® Protective Coatings