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Residue and flaking on HDG Basket Tray

Hi....

I work for an IT infrastructure company who is currently installing the low level containment for a data centre. The low level containment is hdg basket tray. We have had it delivered and it has a residue film, flaky bits on it. I have spoken to the manufacturer and they have been very helpful and explained that the process does lend itself to leaving a residue. Our concern if brushed/cleaned down that there is the potential for a flake to go air bourn and short out equipment.

I really want to know if this residue is common and would be interested in an independent view.

Cheers Aaron

Aaron Anthony
Project Manager - United Kingdom
October 29, 2010

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November 2, 2010

You have not been very specific on what the flaky residue looks like.
It could be a powdery white dust like substance? This is known as white rust, or wet storage stain. Its mostly zinc oxide, zinc carbonate and other oxidation products. It forms when the galvanized steel is kept wet for a while. It can be removed by brushing, washing or similar. This is a common complaint. It often is complained about from those expecting an aesthetic appearance of a non aesthetic coating system, one designed for corrosion protection not aesthetics.
This residue is mildly corrosive, not something to have in an IT room. Its non-conductive though.

It could be flakes of zinc. This is a rare complaint. It sometimes happens on fine (say 1-2 mm dia wire) mesh products due to surface tension in molten zinc causing filmy zinc to bridge the holes in the mesh then pop (bit like blowing bubbles with detergent on mesh), leaving fine think zinc flakes adhering to one or more of the wires of the mesh. This is zinc metal, conductive and not something to have in an electrical environment where exposed terminals might be shorted.

Can you give more info on appearance?

Galvanizing isn't suitable for some applications.

Geoff Crowley
Crithwood Ltd.
Westfield, Scotland, UK