Quality standard of AH Hardt sp.j.
AH Hardt sp.j. regularly examines the resistance of its items to corrosion.
The test for the corrosion speed of the lightning protection system was performed in a salt chamber in neutral salt spray according to PN-76 H-04603 and PN-EN 60068-2-11 standards, and it was continued until red rust occurred. The test checked the time until white rust and the time between the appearance of white rust (the % of the item’s surface) and the appearance of red rust, which ended the test. White rust – oxidation of the outer layer – disqualifies an item if it occurs earlier than after 66 hours (Standard 62305).
At the beginning of 2009, we sent our typical items, items with different insulation and items according to a modified galvanising and coat-protection technology to a galvanisation laboratory. The test results are provided below. Each time we achieved resistance until red rust of over 500 h for all elements, over 600 h for other insulation, and almost 900 h for modified galvanising and layer protection technology. We must add that we zinc-coat screws and caps by ourselves since those available on the market are of very poor quality. We have also decided to analyse the items manufactured by our competition.
The result of 48 h until red rust for the competitors’ items speaks for itself. The resistance of our items is over 500 h. This lets us provide 3- and 5-year anti-corrosion warranties for our products, zinc-coated in our galvanising shop.
Half a year later we decided to repeat the tests using more items made by various manufacturers. We purchased similar items from four Polish manufacturers and one from
a German company. We also added our standard items to the test.
For two Polish companies, item resistance until red rust did not exceed 48 h, for the third one – 72 h, while the fourth one had the best result of 144 h. Our items tested at the same time once again achieved more than 500 h. Measurement of the competition’s zinc layer thickness points to galvanisation in slightly acid baths. Such baths result in considerable fluctuations in zinc layer thickness. Hence the thickness value ranging from 3 to 11 µm
or 5 to 11 µm. Such fluctuations makes an item corrode almost immediately in places where the coating is too thin. The manufacturer also saves on coating insulation. Hence the poor results.